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ProceedingsInternational Workshopon GroundnutsInternational Crops Research Institute for the Semi-Arid Tropics

Proceedings of theInternational Workshopon GroundnutsICRISAT CenterPatancheru, India1 3 - 1 7 October 1980International Crops Research Institute for the Semi-Arid TropicsICRISAT Patancheru P.O.Andhra Pradesh 502 324, India

Correct citation: ICRISAT (International Crops Research Institute for theSemi-Arid Tropics). 1980. Proceedings of the International Workshop onGroundnuts, 13-17 October, 1980, Patancheru, A.P., India.Workshop CoordinatorandScientific EditorR. W. GibbonsPublicationEditorJ. V. MertinThe International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)is a nonprofit scientific educational institute receiving support from a variety ofdonors. Responsibility for the information in this publication rests withICRISAT or the individual authors. Where trade names are used this does notconstitute endorsement of or discrimination against any product by theInstitute.

ContentsF o r e w o r dviiO p e n i n g S e s s i o n 1Welcome and Overview of ICRISAT L. D. Swindale 3Research at ICRISAT — An Overview J. S. Kanwar 6ICRISAT's International Cooperative Program J. C. Davies 8The ICRISAT Groundnut Program R. W. Gibbons 12S e s s i o n 2 — R e s e a r c h O r g a n i z a t i o n a n d D e v e l o p m e n t 17Indian Coordinated Research Project on Vikram Singh 19Oilseeds with Special Referenceto GroundnutThe Role and Function of the IHRO in P. Gillier 25Groundnut Research and DevelopmentPeanut Collaborative Research Support C. R. Jackson and 31Program PlanningD. G. CumminsResearch and Extension Inputs Resulting Ray O. Hammons 33in High Yields of Groundnuts in the USASummary of Discussion — Session 2 40S e s s i o n 3 — G e n e t i c s a n d B r e e d i n g 45Groundnut Genetic Resources at ICRISAT V. R. Rao 47Breeding Methodology for Groundnuts A. J. Norden 58Groundnut Breeding at ICRISAT S. N. Nigam, S. L. Dwivedi, 62and R. W. GibbonsSummary of Discussion — Session 3 69S e s s i o n 4 — C y t o g e n e t i c s a n d Utilization of W i l d S p e c i e s 71Cytogenetic Investigations in the Genus H. T. Stalker 73ArachisUtilization of Wild Arachis Species at A. K. Singh, D. C. Sastri, 82ICRISATand J. P. MossSummary of Discussion — Session 4 91S e s s i o n 5 — C r o p N u t r i t i o n a n d A g r o n o m y 93Increasing Nitrogen Fixation of the J. C. Wynne, G. H. Elkan, 95Groundnut by Strain and Host Selection and T. J. Schneeweis

Studies on Nitrogen Fixation by Groundnut P. T. C. Nambiar and 110at ICRISATP. J. DartPhysiological Basis for Increased Yield D. E. McCloud, W. G. Duncan, 125Potential in PeanutsR. L. McGraw, P. K. Sibale,K. T. Ingram, J. Dreyer,and I. S. CampbellGroundnut in Intercropping SystemsM. S. Reddy, C. N. Floyd, 133and R. W. WilleySummary of Discussion — Session 5 143S e s s i o n 6 — G r o u n d n u t E n t o m o l o g y 147Resistance of Groundnuts to Insects W. V. Campbell and 149and MitesJ. C. WynneGroundnut Pest Research at ICRISATP. W. Amin and158A. B. MohammadSummary of Discussion — Session 6 167S e s s i o n 7 — G r o u n d n u t P a t h o l o g y 169Cylindrocladium Black Rot (CBR) Disease Marvin K. Beute 171of PeanutSclerotinia Blight of Groundnut — a D. Morris Porter 177Disease of Major Importance in the USAGroundnut Foliar Diseases in the United States D. H. Smith 186Research on Fungal Diseases of Groundnut P. Subrahmanyam, 193at ICRISATV. K. Mehan,D. J. Nevill, andD. McDonaldStudies of Resistance to Foliar Pathogens D. J. Nevill 199International Aspects of Groundnut Virus D. V. R. Reddy 203ResearchGroundnut Virus Research at ICRISAT A. M. Ghanekar 211Summary of Discussion — Session 7 217S e s s i o n 8 — C o u n t r y R e p o r t s 221Asia and AustraliaAustralia K. J. Middleton 223Bangladesh M. A. Hamid 226Burma U. Win Naing 230MalaysiaHalim B. Hamat and233Ramli B. Mohd. NoorThailandArwooth Na Lampang,Terd Charoenwatanaand Dumrong Tiyawalee237South AmericaArgentina Jose R. Pietrarelli 241Brazil A. S. Pompeu 244Venezuela Bruno Mazzani 247iv

AfricaMalawi P. K. Sibale and C. T. Kisyombe 249Mali D. Soumano 254Mozambique A. D. Malithano 257Niger A. Mounkaila 262NigeriaS. M. Misari, C. Harkness, 264and A. M. FowlerSenegal J. Gautreau and O. De Pins 274SudanH. M. Ishag, M. A. Ali,282and A. B. AhmadiTanzania A. Bolton 285Z i m b a b w e G. L. Hildebrand 290Summary of Discussion — Session 8 297S e s s i o n 9 — P l e n a r y S e s s i o n 301Chairmen Summaries 303General Discussion 308A p p e n d i x 1 — Poster S e s s i o n P a p e r s 313A p p e n d i x II — P a r t i c i p a n t s 319v

F o r e w o r dOne of the important functions of an international research institute is theholding of workshops, conferences, and symposia where delegates frommany parts of the world can meet together to discuss research problems andprogress. ICRISAT has hosted many such workshops, but this is the first onethat has been held solely for groundnuts.It was an appropriate time to hold such a meeting, as our program atICRISAT Center is almost fully staffed and we are preparing to place staff atresearch stations in Africa.The research program of ICRISAT presented at the Groundnut Workshopand the deliberations and discussions thereon clearly indicate that theInstitute's main lines of research, aimed at overcoming major yield-reducingconstraints, are appropriate and welcome.One area that undoubtedly needs early and more concentrated attention isdrought resistance. It is alarming to hear of the devastation that has affectedgroundnut production and reduced the cultivated area, particularly in the drierzones of West Africa.We are pleased that the groundnut physiology program is now under way,and we look forward to fruitful cooperation with our colleagues in nationalprograms.It is also pleasing to find that the Indian groundnut research program isbeing strengthened and that a new national center is being formed in the highproduction area of Gujarat State. This is very appropriate because of the largedeficit of vegetable oils in India, which in turn means that precious foreignexchange has to be spent on imports despite India being the largest groundnutproducer in the world.There is undoubtedly also a pressing need in many other parts of the worldto increase groundnut production and initiate more research. We believe thatICRISAT can help.On behalf of ICRISAT I would like to thank all the delegates, many of w h o mtravelled far to Hyderabad, for making this workshop a success.L D. SwindaleDirector Generalvii

Opening SessionChairman: R. W. Gibbons

W e l c o m e a n d O v e r v i e w o f I C R I S A TL. D. Swindale*It is w i t h very considerable pleasure that Iwelcome you to ICRISAT and to our first InternationalWorkshop on Groundnuts. This morning Iwant to give you an overview of ICRISAT and itsactivities. I will not deal very m u c h w i t hgroundnuts because you are going to discussthis subject in depth over the next f e w days.ICRISAT is the International Crops ResearchInstitute for the Semi-Arid Tropics. Our logoshows that we work on cereals, and on legumes,and because we are working in the semi-aridtropics, our logo also reminds us of the importanceof every drop of water, the scarcestnatural resource in the region.There are four objectives in the mandatestatement of ICRISAT — (1) to serve as a worldcenter for the improvement of the genetic potentialfor grain yield and quality of groundnuts,sorghum, pearl millet, pigeonpea, and chickpea;(2) t o d e v e l o p f a r m i n g s y s t e m s t o help increaseand stabilize agricultural production throughmore effective use of natural and human resourcesin the semi-arid tropics; (3) to identifysocioeconomic and other constraints to agriculturaldevelopment in the semi-arid tropics, andto evaluate alternative means of alleviatingthem through technical and institutionalchanges; and (4), to do what we are doingtoday — assisting national and regional researchprograms through cooperation and bysponsoring conferences, operating internationaltraining programs, and assisting extensionactivities. These are the four objectives ofthe mandate statement of ICRISAT.We generally define the semi-arid tropics(SAT) in terms of the distribution of rainfalland the potential evapotranspiration (PET)throughout the year. The rainfall tends to occurmostly in a few months of the year while theevapotranspiration exceeds rainfall for most ofthe year. But for a short period, long enough forcropping, the reverse is true, and rainfall ex-* Director General, ICRISAT.ceeds PET giving us normally enough water togrow crops, and a little extra. One of the thingsthat we are doing in ICRISAT is trying to determineif we can make good use of that little extra.The semi-arid tropics cover a very large area ofthe world including a large part of the Africancontinent, most of the South Asian subcontinent,appreciable and significant areas in theAmericas, other parts of Asia, and Australasia.Much of the world production of the fiveICRISAT crops is consumed as human food inthe SAT. The crops are low in cash value andwith one exception (groundnuts), do not enterworld trade to any extent. There has been verylittle research in the developed countries onmost of these crops, mainly because they aretropical and subtropical crops, and inadequateresearch in the developing countries. Fertilizerresponsivegenes are yet to be discovered,particularly for the legumes. The crops aregrown mostly under rainfed conditions, theyields are low and unstable, and high inputtechnology has not yet been feasible. Veryimportant to us is the fact that they are grown bysubsistence farmers in the poorest countries ofthe world.We are not discouraged by all these thingsbecause we believe that the potential for productionis very high. Here at ICRISAT, underrainfed conditions, we have already obtainedseveral times the average yields of these cropsunder low-input conditions, and as you know,much higher yields again are possible in moreintensive agriculture. We believe the potential isthere — we know the potential is there. It is ourjob to unlock the potential and bring it to the useof the small farmers. They have limited meansand limited inputs and are without the benefitsof regular regional irrigation. They constitute aparticular target group for which ICRISAT hasbeen charged to work by the ConsultativeGroup on International Agricultural Research,which is the donor group behind us. It is ourresponsibility to concentrate our efforts for thebenefits of this target group, but naturally we3

also work for the other producers of our crops.This is particularly true of the crop that interestsy o u — groundnuts. The small farmer of limitedmeans is a c o m m o n sight here in India,and also in the African countries, CentralAmerica, and the other countries covered b y t h eICRISAT mandate.Although the small farmer is ourtarget group,we also have a client group, which consists ofthe scientists, and workers in the national researchinstitutions, extension, and action agencies.We are an international institute, and it isnot our responsibility to undertake the work ofnational programs of scientific research or extension.We work for and help our client groupwith our results so that they in t u r n , will help thesmall farmer. We fashion our products so thatthey will help scientists help the small farmer.That is the way in which we work.At ICRISAT Center, our crop improvementwork is conducted on t w o major soil types of theSAT. One is the black deep Vertisol (the blackcotton soils), and the other is the red soil with asandy t o p and a clay subsoil. This latter type weknow as Alfisol. In Africa, however, we tend towork much more upon very sandy soils like thesoils on the outskirts of Niamey in Niger wherethere is a little concentration of clay in the lowerparts of the horizon but, for the most part, thesoil is very sandy, and has a very low exchangecapacity and very l o w nutrient status.Regarding our programs in West Africa, wehave scientists working together with nationalprograms in Senegal, Mali, Upper Volta, Niger,Nigeria, and also in Sudan, and in East Africa.Our major effort at the present time is inOuagadougou in Upper Volta, and we are alsotrying to establish a center at Niamey in Niger.At the present time, we do not have a programworking on groundnuts in Africa but our donorgroup, the CGIAR, has agreed that we should.In the near future, this year and next year,we hope to establish an ICRISAT groundnutprogram in Africa, possibly in t w o differentlocations or localities, with the first one probablybeing in Malawi.In carrying out our mandate for the smallfarmer and our client scientists, we concentratefirstly upon collecting germplasm f r o m all overthe w o r l d . We have many lines now. This hasbeen done w i t h the considerable help of theIndian Government quarantine services andparticularly the Central Plant Protection TrainingInstitute (CPPTI) which has undertaken theresponsibility of quarantine services for materialcoming into India for ICRISAT and its releaseto us. We are interested in the highly responsiveand stable high yielding varieties. We test forstability in an international network at Hissarin northern India, at ICRISAT Center, atBhavanisagar in southern India, at Kamboinsein Upper Volta, and in the other countries that Ihave mentioned in West Africa.We carry out research on diseases of our fivecrops and we also work upon insects includingthe pod borer, which is probably the worstinsect pest in the tropical world. We also workupon weeds, including resistance to parasiticweeds such as Striga which occurs in the cerealcrops both in India and Africa. This is a veryserious pest of the cereal crops and there aresimilar parasitic pests upon groundnut andother legumes.In addition to our work on crop improvement,we have a farming systems program and a programin socioeconomics. Trying to overcomethe constraints that small farmers face is verydifficult and you cannot do it if y o u do not knowwhat they are. So we are undertaking a considerableprogram, probably the largest programin social sciences in any of the internationalagricultural research centers, in order to understand,quantitatively if possible, the exactreasons for the lack of development amongstthis group of people in the SAT. For example,we are trying to understand at first hand w h yareas of Vertisols, the deep black soils, arebeing left fallow when there is plenty of water inthe rainy season. What are the reasons thatcause the farmers to do this and are theysolvable by scientific research?We have d o n e a great deal of work in thisparticular field and recently we released adocument summarizing our results to date onfarming systems components for selectedareas in India. This evidence was gained overabout 8 years of work here and in conjunctionwith the All India Coordinated Research Projects.We can now say how to overcome manyof the constraints to development in theseareas, particularly in the areas with deep blacksoils and where the m o n s o o n rainfall is reliable.Under these conditions we think we now havethe elements, indeed most of the components,of a new farming systems technology. We aren o w discussing w i t h the Indian national pro-4

gram the way in which this can be tested on alarger scale than w e , as an international institute,are able to handle. Our new technology isbased upon a watershed concept in which wetry to deal w i t h the whole watershed as a unit. Itincorporates improvements in cropping systems,in land and water management, in implements,in institutions, and in h u m a n activities.All these changes are necessary in orderto implement the improved technology. Fortunately,although the package is complex it ispossible to implement it step by step. We have agood idea of w h a t are the lead practices that canbe relied upon to start the farmers in thisprocess of development and then allow t h e m topick up other practices at later stages. Dr.Kanwar will probably discuss this with y o u inhis paper.I have noticed that the Groundnuts Workshopprogram does not include the training aspectsof ICRISAT or the possibilities for training hereat ICRISAT Center, so I thought I would mentionthis myself. There are people here, particularlyfrom the developing countries, w h o might wishto see that their younger colleagues have opportunitiesfor training here. There are alsopeople f r o m developed countries w h o mightlike to know that we have training programs forgraduate students and postdoctoral candidates.ICRISAT Center provides five major types oftraining — international internships, researchfellowships, research scholarships, in-servicetraining programs, and apprenticeships.The international internships are for postdoctoralfellows f r o m our donor countries togive t h e m an opportunity to work for a while atICRISAT in a developing country. Researchfellows are M.Sc. and Ph.D. degree holdersfrom SAT countries w h o work with ICRISATscientists on specific problems for one or moreyears. We also have research scholars w h o arestudents of overseas universities and of universitieshere in India. These scholars undertakecertain aspects of their research program hereat ICRISAT under the guidance of an ICRISATscientist with the cooperation of their thesis ordissertation supervisor f r o m their o w n university.Our largest training program is the in-serviceprogram. We bring in young scientists andextension workers for a very concentratedprogram of training, usually for one croppingseason, on all aspects of how to grow a particularcrop and h o w t o conduct good field researchwith it. Our training philosophy is problem-areaand skill-development centered; practical experienceout in the field is the heart of ourtraining program. We try to teach our traineesthe importance of socioeconomic relationshipsassociated with new technology. We insist thatthey undertake individual experiments and demonstrationsand learn something about managerial,communication, and leadership skills.We have training programs in crop improvement,crop production, and in farming systems.We teach people to learn by getting them to dothings for themselves, such as getting behind acou pie of bullocks for thefirst t i m e in their life orplanning their o w n experiments, organizingthem, laying them out in the field, and thenliving with the results even if the results are notsuccessful.The students learn f r o m both their successesand failures. W h e n they receive their certificatehere at the completion of their training program,they can go back h o m e w i t h t h e f eeling that theyhave learned something. They will have theconfidence to go out in the field and work eitherin research or extension and not find that theyhave only a great deal of academic knowledgew i t h very little practical skill in the growing ofcrops.Thank you very much. You are indeed welcomehere and I hope that you have an enjoyableand profitable conference.5

Research at ICRISAT — An OverviewJ. S. Kanwar*It is my great pleasure indeed to welcome you tothe ICRISAT Center and to participate in thisworkshop.Dr. Swindale in his address has given you thespectrum of all the activities of ICRISAT — itsgoals, mandate, problems, approaches, targets,achievements and h o w we function. Becauseour statistician tells us that replication is essentialin scientific agriculture, I am going toreplicate Dr. Swindale's address just toimprove the reliability of the results and maket h e m better interpreted and better understood.I wilt give y o u a brief idea about the activitiesof our fifteen programs. Six of them are calledresearch p r o g r a m s , seven are the researchsupport programs and the other t w o , that isInformation and Administration, are our supportprograms.ICRISAT has to work for t w o groups of people.There is the target group consisting of resourcepoor farmers. The other group, the so calledclient group, is composed of scientists, extensionworkers and technicians.In t h e semi-arid tropics, SAT, t h e farmertarget group has to produce under very difficultclimatic conditions. There is a short rainy seasonfollowed by a long dry period. The rainfallreceived is also very variable and no t w o yearsare the same. Sometimes the rainfall is verylight and sometimes it is so heavy that the farmersexperience flooding and drainage problems.In the SAT, there are Alfisol and Vertisol soiltypes. The former are red soils, low in fertilityand moisture-holding capacity, and they areused for the cultivation of groundnuts and othercrops. The Vertisols are black soils with a highmoisture-holding capacity, but with low fertilityThey are very difficult to manage particularlyduring t h e kharif season, i.e., the monsoon orrainy season, w h e n they should be cropped butm a n y of them are left fallow.* Director of Research, ICRISAT.Regarding our strategies for research, thefirst emphasis is on assembling, evaluating andutilizing the germplasm resources. This is followedby striving to build higher yield potentialand yield stability in the hybrids, compositesand experimental varieties. We are also interestedin incorporating disease and pest resistance,and better nutritional qualities into ourmandate crops.Not only do we attempt to improve grain acceptabilitybut we also try to improve the lysinecontent of sorghum and millet grains, and thesulphur-bearing amino acid content of thepulse seeds.We are developing a computerized system ofrecords for our 50 000 germplasm lines w h i c hhave been accumulated over the last 6 - 7 years.Not only do we receive germplasm f r o m manycountries, but we also distribute thousands ofsamples to a great many national programs inthe world.The field experiments of ICRISAT scientistshave shown that all of the mandate crops haveg o o d p o t e n t i a l f o r increased yields underrainfed conditions as indicated in the followingtable:Experimental yield atICRISAT (kg/ha)Average High fertility Low fertilitySAT yield and g o o d and averageCrop (kg/ha) management managementSorghum 842 4900 2627Pearl Millet 509 3482 1636Chickpea 745 3000 1400Pigeonpea 600 2000 1000Groundnut 794 2573 1712The problem is that unless the farmers areable to get those types of yields, w e c a n n o t get abig improvement in national production.Regarding disease research at ICRISAT, we6

disseminate resistant material developed hereto the national programs for screening in theircountries, particularly at the hot spots in thei n t e r n a t i o n a l nursery s y s t e m . Diseases onwhich ICRISAT is working include d o w n y mildewon sorghum and pearl millet; ergot onpearl millet; grain molds and charcoal rot ofs o r g h u m ; sterility mosaic in pigeonpea; wilt ofchickpea; and leaf spots and rust of groundnut.In entomology, we have evolved a screeningtechnique for shoot fly and we are also developingone to screen for pod borers.Using a technique developed by ICRISAT, wecan screen plants for d r o u g h t tolerance, inw h i c h different m o i s t u r e level regimes areapplied to the plants being tested.ICRISAT scientists are also s t u d y i n g theparasitic weed Striga. Apart f r o m being a seriousproblem in Africa, it is n o w causing considerableconcern in India too and it is beingscreened here.Recognizing that the ultimate reality of whateverimproved material we produce is its suitabilityand acceptance, we test newly developedmaterial with a tasting panel. What is suitablefor India may not be suitable for Africa and whatis suitable for the Sudan may not be suitable forNigeria and so on.Our Economics P r o g r a m has t w o m a j o rs u b p r o g r a m s — p r o d u c t i o n e c o n o m i c s andm a r k e t i n g economics. They are e x a m i n i n gmarketing problems and how to improve thepossibilities of farmers making more profits.We are concerned with the poor fertility ofsoils, and the drainage problems associatedwith the black soils, i.e., the Vertisols. Phosphate,zinc and sulphur deficiences have beennoted.ICRISAT has developed a watershed conceptin its Farming Systems program so thatwater movement f r o m the higher levels is conservedby various techniques instead of all m o v -ing to the lower levels. I w o u l d like to emphasizethe point that the availability of water acts as acatalyst for a new agriculture. When farmersfind that they have some water available, theyare prepared to take risks.In the farming system developed here, broadbeds and furrows are used and appropriatemachinery is necessary to make them. Also, asuitable cropping system must be incorporatedinto the overall production scheme.Materials are tested here at ICRISAT under arange of e n v i r o n m e n t a l situations such asunder pesticide protection; without pesticideprotection; irrigated and nonirrigated conditions;and in low and high fertility areas.With new developments, we are very consciousof thefactthat unless a farmer sees a t w oor three-fold benefit, he will not be very enthusiasticabout adopting a new technique ornew variety. In particular, under dryland farmingconditions, a farmer is not prepared to take toomany risks because of climatic conditions. Sonaturally, we must find a technology whichgives him good stability in production andalso more benefits.In order to get new developments in technologyand new varieties to farmers, we are involvedin a linkage system for the transfer oftechnology. We have cooperative linkages w i t hvarious international institutes, with nationalinstitutes, and with various other organizations.Fundamentally, the ICRISAT program actsthrough t w o bases — the seed base and the resourcebase. ICRISAT reaches the nationalprograms and they in turn work with the farmers.When a farmer adopts a new variety andcan say at harvest time that he has just obtainedthe largest yield in all his farming life, thenwe know that we have achieved one of ourobjectives — increased agricultural production.7

ICRISAT's International Cooperative ProgramJ. C. Davies*The basic objectives of ICRISAT and the thrustsof the research effort have been explained bymy colleagues, Drs. Swindale and Kanwar. I donot propose to reiterate these, but I w o u l d like tore-emphasize that an important premise, whenthe Institute was established, was that it w o u l dserve to strengthen and support established agriculturalresearch programs and effort, both inthe host country and other nations in the SAT.Clearly, the establishment of a CooperativeProgram was vital in achieving this goal. About50 countries on four continents have some SATareas w i t h i n their boundaries (20 million sqmiles), and the majority of these are less developedor are developing countries. There wasa necessity to determine priority countries,crops, and research areas for maximizing thereturns f r o m resource input — both by way ofstaff and funding in cooperative ventures.V i t a l S t a t i s t i c sI n f l u e n c i n g L o c a t i o n o ft h e C o o p e r a t i v e P r o g r a mSome 6 6 % of the SAT area is in Africa — 24% inW. Africa, 2 2 % in E. Africa, and 20% in southernAfrica. The population of the SAT is around 600million — 56% of which, i.e., about 350 million,live in India (which occupies only 10% of theSAT land surface). About 90 million live in SATW. Africa. The second largest SAT country is inAfrica, the Sudan, which has only a minute 3%of the SAT population in 8% of the land area.These figures highlight the wide differences inland to population ratios which exist in the SATcountries.Populations in Africa are g r o w i n g at an extremelyhigh rate. A further factor which affectedprogram siting was that in the 1970's, adrought situation existed in much of Africa, butparticularly in sub-Sahalian Africa, causing untoldsuffering and misery to millions of people.* Director for International Cooperation, ICRISAT.A study of the statistics for three of ICRISAT'sm a n d a t e crops — m i l l e t , s o r g h u m , andg r o u n d n u t s — indicate their importance in theSAT, both in hectarage and production terms(Table 1). However, average yields are low.Cereals are very important in the SAT and t w oof ICRISAT's mandate crops, millet and sorgh u m , are vitally important, especially in view oftheir comparative drought tolerance. Millet isimportant in almost all the West African countriesand India, and sorghum in several countries(Table 2). In Eastern Africa, millet is of greatimportance in Sudan and Tanzania. Sorghum isof prime importance in the Sudan and of considerableand possibly increasing importance inTanzania, and to an extent in the other countries(Table 3).These facts together with the predictions of anumber of agencies that food deficits will be af e a t u r e of t h e 1980's in A f r i c a , g r e a t l yinfluenced the development, crop choice andsiting of our initial cooperative research effortsin the West African region.P r o g r a m D e v e l o p m e n ta n d S t r u c t u r e i n W e s t A f r i c aa n d E a s t A f r i c aIn early 1975, UNDP and ICRISAT entered into a3-year contract that had as its prime objectivestrengthening of existing West African programsand development of higher yielding andstress resistant sorghums and millets. The projectcovered 12 countries in W. Africa stretchingfrom Senegal to Nigeria; subsequently Sudanwas included. The strategy in the first phasewas to post ICRISAT scientists to existing researchstations at Bambey, Senegal; K a m -boinse (initially Farako Ba), Upper Volta; Maradiin Niger; Samaru in Nigeria; and Wad Medani inthe Sudan — thus ensuring close day to dayand effective collaboration w i t h national programscientists. The ICRISAT scientists posted8

overseas w o u l d also effectively collaboratew i t h the ICRISAT Center at Hyderabad.The first scientist was posted in 1976 and the1977 season was the first full crop year. Thepattern of staffing in the second phase currentlyincludes — a project manager based at Dakar(partly funded by IRAT); a millet breeder andcereal entomologist at Bam bey, Senegal; a sorgh u m breeder (initially UNDP, n o w on core); amillet breeder, a cereal pathologist and agronomistat Kamboinse. The Dutch Governmentassisted with an agricultural engineer.Elsewhere we have a millet breeder at Maradi, amillet breeder and cereal pathologist at Samaru,and millet and sorghum breeders at WadMedani.To this network there have been added in thepast few years an agronomist and a sorghum/millet breeder in Mali under a USAID contract,and under a subcontract to IITA/USAID, a sorgh u m breeder in Tanzania. In the sorghum andmillet crops therefore, a strong interconnectingseries of teams has been formed. This widespread of teams, to a considerable extent, coversthe range of a g r o c l i m a t o l o g i c a l , broadedaphic and food preparation situations exist-Table 1 .S A T a n d w o r l d production o f sorghum, millet, chickpea, p i g e o n p e a , a n d g r o u n d n u t D a t arepresent averages for t h e years 1 9 7 3 , 1 9 7 4 , a n d 1 9 7 5 . ( S o u r c e : F A O , various issues).Area Production YieldCropSAT World('000 ha) ('000 ha)SAT/World%SAT('000 mt)W o r l d('000 mt)SAT/World%SAT W o r l d SAT/World('000 kg/ha) ('000 kg/ha) %S orghumMilletsChickpeaPigeonpeaGroundnut34 553 43 26935 595 70 3529 150 9 9742 669 2 79214 604 19 084805192967720 08218 1095 4061 77711 59452 80046 9596 008185817 8685539909665842509591666794122066760266593669769810085T a b l e 2 .T o t a l a r e a under cereal crops i n t h e S A T c o u n t r i e s i n W e s t A f r i c a a n d India. (Unitsexpressed a s ' 0 0 0 h a ) .Country Maize S orghum Millet Rice WheatIndia 5900.00 16 015.00 18 351.67 39 504.00 20 859.67Mali 91.67 1214.67 204.33 2.00Niger 10.67 715.67 2 651.67 224.00 2.00Nigeria 1612.67 5 980.00 4 906.67 311.00 13.67Senegal 48.33 934.67 74.33Upper Volta 110.00 1 079.34 907.00 42.33T a b l e 3. T o t a l area of cereal crops in Eastern A f r i c a . ( U n i t s expressed as ' 0 0 0 h a ) .Country Maize S o r g h u m Millet Rice WheatBotswana 71.67 100 10M a l a w i 1033.33 120 45Zambia 1050.00 80 134.67 2.33 1.67Kenya 1550.00 209 80.67 7.00 120.67Sudan 85.00 2705.67 1170.33 8.33 294.00Tanzania 1300.00 338.33 213.33 180.00 50.009

ing in the sorghum and millet areas of West andEast Africa.As the program developed it became clearthat further strengthening of the research effortwas required. In the early part of Phase II of theUNDP program, it was decided to strengthenthe team at Kamboinse and to assist with theimprovement of physical facilities and the farmlay-out. This helped in forging links w i t h theOAU/SAFGRAD p r o g r a m . Currently ICRISAThas four scientists on its staff in W. Africafunded from this program — one soil scientistposted at Kamboinse, and three shortly to beposted to Nigeria, including a sorghum breeder,an agronomist and an entomologist, all with anessentially regional program of work.At Kamboinse, the staff has also been augmentedby a Striga scientist under a restrictedcore IDRC grant and by the posting of a corep r o g r a m e c o n o m i s t to initiate village levelstudies and studies on adoption of improvedtechnology. A core funded entomology posthas also been created. The station will mainlybe concerned w i t h the development of improvedsorghum cuitivars and farming systemsfor the 800 mm rainfall areas of W. Africa. Thelocation of core staff indicates the c o m m i t m e n tof ICRISAT to a long-term research effort inAfrica.In view of the importance of millet in theSahelian area, w e a r e negotiating an agreementw i t h the Government of Niger to site a centernear Niamey. This will deal with pearl milletimprovement and farming systems, which areessentially concerned with millet/groundnuts inthe 600 mm sandy soil situations, which are soc o m m o n in W. Africa. Recruitment of some stafffor this situation is under way.C o o p e r a t i v e P r o g r a m si n O t h e r A r e a sIn addition to these programs, ICRISAT currentlyconducts a s o r g h u m program in CentralAmerica, based at CIMMYT in Mexico, whichfollows up on a previous program that wasaimed mainly at production of cold tolerantsorghums for higher elevation areas. This programis currently being diversified and is producinggood quality white sorghums, which areproving to be very useful in several countries int h e region where sorghum is used as a humanf o o d . Several lines are already being multipliedby national programs, and these are useful foradmixture with maize for making tortillas.T w o years ago it was recognized that ICRISATshould have a research effort on chickpea outsidethe host country, as this w o u l d be valuablein breeding the kabuli type. This program wasbased in the Middle East. A t e a m of one breederand one geneticist is currently based in ICARDA,at Aleppo, Syria. The emphasis in breeding willshift slightly in the future towards breeding fordisease resistance.Role of ICRISAT Scientistsin the Cooperative ProgramAll ICRISAT scientists posted to the CooperativeProgram have a tripartite role to play:1. They make a direct contribution to the nationalprogram of the country in whichthey serve. This may be large or small,depending on the strength of the nationalresearch program. They f o r m an effectivelink through which genetic material andinformation flows to national scientistsf r o m o t h e r ICRISAT s c i e n t i s t s i n t h eCooperative Program and f r o m ICRISATCenter, Hyderabad.2. They make an increasing contribution toregional programs by assisting w i t h exchangeof genetic material, particularlythrough organization of or assistance withthe assembly of regional trials, but alsothrough personal contact and informationexchange through visits.3. They have an important role in carryingout experimentation, including conduc'tingnurseries,whichfeed back informationto ICRISAT Center and other ICRISAT scientistsin the Cooperative Program, on theperformance of material under a range ofclimatic, disease, pest and edaphic conditions.Such information is crucial to buildingup a good data base and developinglong-term fully integrated strategies forcrop improvement and farming systemswork. The exchange is not all one way,e.g., A f r i c a has already p r o v i d e d t h eCenter program w i t h useful genetic materialfor development of d o w n y m i l d e w resistantlines of pearl millet for the Indiansubcontinent.10

Results flowing f r o m the program to date aremost encouraging in all three roles. The performanceof improved cultivars vis-a-vis localland race materials is being assessed and lineshave been developed which are superior to cultivarscurrently being grown.Many lines having stress resistance havebeen identified and this resistance has beentested across a range of environments. The increasingamount of information obtained on thequality characteristics of improved s o r g h u mand millet strains for preparation of local foodshas been particularly useful. This is cruciallyimportant in ensuring acceptance of improvedcultivars by small farmers.T r a i n i n gThis topic was dealt w i t h earlier in the s y m -posium by Dr. Swindale; however I w o u l d liketo emphasize that this is a very important areaof activity. Cooperative program scientists, incollaboration with national scientists, have avery useful role in identifying technicians andscientists for training at ICRISAT Center. A d d i -tionally, they have initiated training and lecturecourses locally in several countries to assist instaff development. The training effort is recognizedas b e i n g of g r e a t i m p o r t a n c e instrengthening national research efforts and isan activity on which we place very great store.F u t u r e D e v e l o p m e n t s i n t h eC o o p e r a t i v e P r o g r a mIn spite of the fact that groundnut figures p r o m -inently in Table 1 with a hectarage of over 14million in the SAT, our program to date overseashas been negligible. This is largely becausegroundnut was added to our mandateonly relatively recently and much effort hasbeen expended to date in building up ourg e r m p l a s m base a n d a c t i v i t i e s a t t h eHyderabad Center. We are currently investigatingthe possibility of initiating a program ongroundnuts in central Africa and have plans tostart work in West Africa, as soon as the centerin Niger is established. Both breeding andpathology will be covered in the first phase,t o g e t h e r h o p e f u l l y w i t h m i c r o b i o l o g i c a lstudies, when funding is identified.In the immediate future we intend to concentrateon the establishment of the Niger Center,which will cater for both groundnut and millet,expanding our program on farming systems inUpper Volta, and developing a program in thisfield of endeavor for the sandy soil, low rainfallareas of W. Africa, basing the program in Niger.We are collaborating with the Government ofMali in establishing a research center at Cinzanafor work on crop improvement and farming systemsin that country.ICRISAT has been requested by the Heads ofState of Southern African States to develop aregional center and we are actively pursuingthis. A fact-finding mission will leave for thearea within 3 weeks, and it is hoped that workingagreements may evolve from this.We look forward to cooperating fully with nationalprograms in the great task ahead of helpingthe small farmer of limited means in theSAT. These farmers have been neglected in thepast, but they form a major component of thepopulations in m o s t S A T areas. Thetask of helpingthem should not be minimized, the roadahead is difficult and tortuous, and given thedifficult conditions u n d e r w h i c h t h e f a r m e r s t o i l ,progress is unlikely to be punctuated by bigbreakthroughs. The task will take persistence,continuity and patience. I know that we atICRISAT can assist you in your endeavors withthe groundnut crop, and I hope that f r o m thisconference will c o m e firm plans of action andguidelines on tackling the many problems weall face in assisting the farmers in the variouscountries represented here.May I wish the Workshop every success in itsdeliberations.11

The ICRISAT Groundnut ProgramR. W. Gibbons*G r o u n d n u t s i n W o r l dA g r i c u l t u r eThe cultivated groundnut, Arachis hypogaea L,is a native of South America and the crop is n o wg r o w n throughout the tropical and w a r mtemperate regions of the world. Althoughgroundnuts are predominantly a crop of thetropics the approximate limits of present commercialproduction are between latitudes 40°Nand 40°S.In 1978, it was estimated that just over 18.92million hectares were planted and 18.87 milliontonnes were harvested at an average yield of998 kg/ha (FAO Trade Statistics). Asia is thelargest producer (.10.9 million tonnes), followedby Africa (5.2 million tonnes). North andCentral America (1.98 million tonnes) and SouthAmerica (0.8 million tonnes).Of the individual countries, India is the largestproducer in the w o r l d (6.2 million tonnes), followedby China (2.8 million tonnes), USA (1.8million tonnes) Senegal (1.0 million tonnes),Sudan (0.8 million tonnes) and Nigeria (0.7million tonnes). Approximately 8 0 % of worldproduction comes f r o m the developing countriesand 6 7 % of the total is produced in theseasonally dry rainfed areas of the semi-aridtropics (SAT).P r o d u c t i o n C o n s t r a i n t sin t h e S A TYields in the SAT are low, around 800-900kg/ha, compared to yields of approximately2500 kg/ha in the developed world (Gibbons1977). The major constraints are pests, diseases,and the unreliable rainfall patterns of theSAT. Apart f r o m the natural hazards whichrestrict production, there are relatively small* Program Leader, Groundnut Improvement Progr a m , ICRISAT.numbers of well trained, specialist groundnutresearchers available.Although groundnuts are often regarded as acash crop, the necessary inputs are often notavailable to small-scale farmers to control pestsand diseases, for example, even when appropriateresearch recommendations have beenmade. Very often these recommendations havebeen based solely on trials conducted on experimentalstations, and not under conditionswhere the farmer actually grows groundnuts.Few research programs in the SAT haveconcentrated on breeding for resistance to themain factors which presently limit production.Some exceptions are the production and releaseof cultivars resistant to rosette virus inAfrica and cultivars resistant to drought inSenegal (Gillier 1978).T h e I C R I S A T G r o u n d n u tI m p r o v e m e n t P r o g r a mB a c k g r o u n dIn 1974 a team of four consultants was invited toHyderabad to review world research needs ofgroundnuts, to consider whether ICRISATought to help meet these needs and, if so, tosuggest a possible program of internationalresearch. It was concluded that the crop didrequire international research, w o u l d be anappropriate subject within the mandates of theinternational research system, and that ICRISATwas the appropriate Center as groundnuts areprimarily a crop of t h e S A T ( B u n t i n g e t a l . 1974).The consultants considered that the cropneeded international research because (1)groundnut research at national stations in mostcountries w o u l d benefit f r o m internationalcooperation, exchange of information, training,and in particular by the formation of a worldgermplasm base, and (2) groundnuts are animportant food crop in many developing nationsand the fact that it is also a cash crop12

should be no bar, as by selling crops, farmershelp to feed the nations as a whole.In 1976 a program of research was presentedto the Governing Board of ICRISAT. The reportwas accepted, and the recruitment of staffcommenced (Gibbons 1976).Research OrganizationWithin the program, at the research center inHyderabad, there are a number of subprogramswhich include breeding, pathology, cytogenetics,microbiology, entomology and physiology.The germplasm subprogram was originallyin the Groundnut Improvement Programbut is n o w part of the Genetic Resources Unit,which has assumed responsibility for all themandate crops of the Institute.The consultants also decided that generalagronomic studies should not form a major partof the program because such problems werelocale-specific and were the responsibility ofnational programs. The consultants also recommendedthat although ICRISAT should befully informed about the insect pests ofgroundnuts, no special program should beformulated (Bunting etal. 1974). However, sincethis report it has become apparent that insectpests are a serious worldwide problem, bothdirectly and as vectors of virus diseases, and adecision has been taken to increase entomologicalresearch at ICRISAT f r o m 1981.Staffing of the center program is now almostcomplete, except for the physiology programwhich has only very recently commenced.ObjectivesThe main objective is to produce high yieldingbreeding lines with resistance to the mainfactors presently limiting production. It is notthe intention to produce finished cultivars, butrather to supply germplasm and breeding lineson which further selection can be practiced incooperating countries. For this, there is a needto know the exact requirements of cooperatingcountries. These requirements vary greatly,even within a country. For example in theSudan, large-seeded, long season groundnutsare g r o w n under irrigation in Wad Medani forexport; but under rainfed conditions farmerscultivate short season cultivars that are moreadapted to those conditions (Osman 1978). InMalawi, long season groundnuts, primarily forthe confectionary export trade, are g r o w n in theplateau areas; cultivars for oil crushing aregrown in the lake shore areas; and short seasoncultivars are adapted to the l o w elevation, drierand hotter areas in the southern part of thecountry (Gibbons 1972).S p e c i f i c R e s e a r c h G o a l sThe program has emphasized the followingspecific research goals:Breeding f o r Resistance to M a j o rDiseases a n d PestsThe most important foliar diseases causingsevere yield losses on a worldwide basis are theleaf spots (Cercospora arachidicola and Cercosporidiumpersonatum) and rust (Pucciniaarachidis). Bunting et al. (1974) conservativelyestimated that the leaf spot fungi alone causethe loss of about 3 million tonnes of kernels peryear. Losses in kernel yields of around 10%have been estimated in the USA, even whenfungicides are routinely applied (Jackson andBell 1969). In the SAT where chemical control isoften not used, losses in excess of 50% arecommonplace (Garren and Jackson 1973). Rustof groundnuts has become a worldwide problemsince 1969 (Subrahmanyam et al. 1979).Intensive programs have been started tosearch for resistance to these diseases, both inthe cultivated and wild species of the genus,and to incorporate this resistance into highyielding and commercially accepted cultivars(Nigam et al., Subrahmanyam et al., Nevill —this conference).Programs are also being developed to breedfor resistance to Aspergillus flavus, which producesa toxic metabolite that affects humanhealth. Breeding lines possessing dry seedresistant to penetration by this fungus havebeen identified in the USA (Mixon and Rogers1973) and are being utilized in the breedingprogram.The germplasm collection is also beingscreened for sources of resistance to suchcommonly occurring fungi as Aspergillus niger,Fusarium sp, Pythium sp, and Rhizoctonia sp.Virus diseases of groundnuts are c o m m o nand serious in the SAT. The major virus dis-13

eases being investigated presently at ICRISATare bud necrosis, caused by t o m a t o spotted wiltvirus (TSWV), and peanut mottle virus (PMV).The germpiasm collection is being screened forsources of resistance, and other methods ofcontrol are also being investigated (Ghanekar;A m i n and M o h a m m a d — this conference).Although insect pests are often limited intheir distribution, some are of w o r l d w i d e distributionand importance. A m o n g the latter arespecies of aphids, jassids, thrips and termites.Some of these species occur at the ICRISATresearch center and germpiasm is beingscreened for sources of resistance in specialpesticide-free areas located on the researchfarm at Hyderabad.Breeding for Earliness, High Yieldand for the Farming SystemsThere is a need to generate high yielding lineswhich are adapted to the harsh conditions of theSAT. As already stated, it w o u l d be important toincorporate into these lines resistance to themajor constraints and stability of yield overyears. However, not every environment hassevere disease or erratic rainfall constraints, sohigh yield per se is also important.Earliness is also an important objective, asgroundnuts fit into relay or sequential croppingsystems where residual moisture is availablef r o m the preceding crop. With the advent ofshort duration rice cultivars, large areas ofSoutheast Asia are now able to g r o w more thanone crop per year. Rice, followed by rice, or anupland crop is n o w a c o m m o n practice andgroundnuts w o u l d fit well in this system.Sources of earliness are being utilized in thebreeding program (Nigam et al. — t h i s conference).Groundnuts are also c o m m o n l y intercropped,particularly in India and Africa. In theGuinea Savanna zone of Nigeria, only 16% ofthe total area is planted as sole crop groundnuts(Kassam 1976). The Groundnut ImprovementProgram is cooperating with the ICRISAT FarmingSystems Research Program in identifyingsuperior groundnut cultivars for the intercroppingsituation (Reddy et al. — this conference).Increasing BiologicalNitrogen FixationThe groundnut is an efficient fixer of nitrogenand attempts are being made to manipulateboth the Rhizobium and the host plant componentof symbiosis to increase nitrogen fixation,and hence groundnut yields. There is also abeneficial effect on the subsequent crop from awell nodulated groundnut crop (Nambiar andDart — this conference).Exploiting the Wild Speciesof ArachisA major component of the program is theutilization of genes f r o m the wild Arachisspecies to improve the commercial groundnutcrop. Resistance to fungal diseases, pests, virusesand drought occur in these species butgenetic manipulation is required to incorporatethese characters into the cultivatedgroundnut because of differences in ploidylevels and other barriers to interspecific hybridization(Moss 1980).Exploiting Physiological Charactersf o r Groundnut I m p r o v e m e n tThis is the last of the programs to be staffed. Theresearch program will be formulated in the verynear futu re and a major part will be to study andexploit characters associated with drought resistance.L i n k a g e sInternational CooperationThe ICRISAT program has been, and stilt is, developinglinkages with other institutions conductingresearch on an international or regional basis.Cooperative programs have been formed withNorth Carolina State University on the transferof groundnut germpiasm, biological nitrogenfixation research and the utilization of w i l dArachis species in the improvement of thecultivated groundnut. A joint program has beenformed between ICRISAT and the USDA inscreening all known sources of resistance torust at the ICRISAT research center. The Governmentof Japan has provided visiting scientistsand facilities for research on viruses. TheInternational Board for Plant Genetic Resources(IBPGR), the germpiasm center in Brazil(CENARGEN), ICRISAT, and national scientists14

from the USA and other countries are cooperatingon groundnut germplasm collections inSouth America. Research on the utilization ofwild species of Arachis, carried out at theUniversity of Reading and financed by theBritish Government, has been of immense helpin the ICRISAT program.Other linkages are being investigated andthere is particular interest in cooperating withnon-groundnut growing countries in the investigationof viruses and whether races of importantfungi occur. These investigations cannot becarried out in India because of quarantine regulationsand the risks of introducing new diseasesinto groundnut growing countries.achieved in the not too distant future. TheCenter program needs to be intensified, particularlyin the fields of entomological andphysiological research, and more cooperationwith national programs is required. In 1981 aregional program is planned for Eastern andCentral Africa, and also in 1981 a second regionalprogram will be set up in West Africa.These regional programs will initially be staffedby a breeder and a pathologist and be fundedf r o m the core budget. If noncore funding becomesavailable, then a microbiologist will beadded to each team.Cooperation w i t h N a t i o n a l ProgramsThe program has developed very close linkswith the Directorate of Oilseeds Research inIndia. The entire Indian germplasm collectionwas placed at the disposal of ICRISAT andcooperative links have been formed with Indianuniversities and research stations. A new nationalcenter for groundnut research has recentlybeen created and located in the state ofGujarat, the largest groundnut producing areaof India. It is envisaged that close cooperationwill develop between ICRISAT and this center.In the relatively short time that the internationalprogram has been operating, links withnational programs interested in groundnut researchhave developed satisfactorily. There isnow a need though to intensify and expandthese links as breeding material is n o w becomingavailable for widespread distribution.The training facilities in groundnut researchat ICRISAT are also becoming available andalready personnel f r o m several countries haveattended courses in such subjects as hybridizationtechniques, disease scoring methodologyand virological techniques. It is intended thatthese facilities should be expanded in thefuture.T h e F u t u r eThere is still a long way to go before markedsuccess can be achieved for the underprivilegedfarmer of the SAT. It is felt however that themajor research emphasis on stable diseaseresistance and high yield will begin to beReferencesB U N T I N G , A . H., GREGORY, W . C , M A U B O U S S I N , J . C ,and R Y A N , J. G. 1974. A proposal for research ongroundnuts (Arachis) by ICRISAT. ICRISAT 38 pp.(Mimeographed), Patancheru, A. P., India.G A R R E N , K. H., and J A C K S O N , C. R. 1973. PeanutDiseases. Chapter 13 in Peanuts-Culture and Uses.American Peanut Research and Education Association.G I B B O N S , R. W. 1972. Peanut disease control inM a l a w i , Central Africa. Proceedings, AmericanPeanut Research and Education Association 4 : 1 - 7 .G I B B O N S , R. W. 1976. Groundnut improvementprogram — priorities and strategies. ICRISAT.(Mimeographed), Patancheru, A. P., India.G I B B O N S , R. W. 1977. An international approach topeanut improvement. Proceedings, AmericanPeanut Research and Education Association 9: 9 7 -100.GILLIER, P. 1978. Nouvelle limites cultures d'Arachideresist ante a la secheresse et a la rosette. Oleaglneux33: 2 5 - 2 8 .J A C K S O N , C. R., and BELL, D. K. 1969. Cercosporaleafspots. In Diseases of peanut caused by f u n g i .University of Georgia Agricultural Experiment Stationresearch bulletin 56. 137 pp.K A S S A M , A. H. 1976. Crops of the West African Semi-Arid Tropics. ICRISAT. Patancheru, A. P., India.M I X O N , A. C , andROGERS, K. M. 1973. Peanuts15

esistant to seed invasion by Aspergillus flavus.Oleagineux 28: 8586.M o s s , J. P. 1980. W i l d species in the improvement ofgroundnuts. Advances in Legume Science (eds.S u m m e r f i e l d and Bunting). Pages 525-535 in Vol 1of the Proceedings of the International LegumeConference, Kew, England, 1978.O S M A N , A. B. 1978. Peanut production in t h e Sudan.Page 12 in Virginia-Carolina Peanut News.SUBRAHMANYAM, P., GIBBONS, R. W., NlGAM, S. N., andR A O , V. R. 1978. Screening methods and furthersources of resistance to peanut rust. Abstract inProceedings, American Peanut Research and EducationAssociation 10(1): 64.16

Session 2Research Organizationand DevelopmentChairman: C. HarknessRapporteurs: J. P. MossD. C. Sastri

Indian Coordinated Research Projecton Oilseeds w i t h Special Reference to GroundnutV i k r a m S i n g h *The evolution of agricultural research in Indiacommenced as early as 1870. Its developmentto the present coordinated research approachhas been expedited by t w o almost simultaneousdevelopments: first, the acceptance of theUppal Committee report (1954-56) to regionalizeresearch on cotton, oilseeds, and millets;and the second, the successful experienceof the coordinated approach applied for the firsttime in maize in the late 1950's. It has beenrefined since then and extended to all the crops,including oilseeds.The cardinal philosophy and the special featuresof the coordinated research as developedover the years (Singh 1980 a), and c o m m o n toall projects, are:1. A multidisciplinary approach to problemsolutions.2. Free exchange and f l o w of material, information,and ideas among researchworkers.3. Compulsory analysis, report, and discussionof research results prior to the futureplanning of the next season/year program.4. Planning the technical program and researchmethods by c o m m o n discussionand consultation among research workersduring annual workshop/meetings.The following six special features also apply:1. The project/program operates on a nationalscale under the direct supervision ofthe Indian Council of Agricultural Research(ICAR).2. All participating institutions/organizationsin the country work as a team to impart anational character to it.3. The project/program has a full-time ProjectCoordinator/Principal Investigator tocoordinate, supervise, and watch the pro-* Project Director, Directorate of Oilseeds Research,ICAR, Rajendranagar, Hyderabad 500 030, A n d h r aPradesh, India.gress for reporting to Council/Government.4. The state provides the required land andlaboratory facilities for the cooperatingcenter(s) located within its bounds.5. The research investment is shared betweenthe Council and state on a 3:1 basis.6. All major disciplines are represented on theproject work on the basis of equivalenceand mutualism.The Oilseeds ProjectThe All India Coordinated Research Project onOilseeds, which was established in 1967, wasraised to the status of Directorate of OilseedsResearch (DOR) on August 1, 1977 in order toenlarge its scope and activities (Vikram Singh1978). The main objective of the Oilseeds ResearchProject is to coordinate, encourage, initiateand plan research activites with a view toproviding a research base which would result inan increase in the productivity and stabilizedproduction of oilseeds in India.The Groundnut ProgramThe specific objectives of the Directorate'sgroundnut program are:1. Development of high yielding varietiespossessing resistance/field tolerance todiseases and pests of economic importancefor the different groundnut g r o w i n gagroecological zones.2. Development of production technologyfor m a x i m u m yield exploitation under irrigatedand unirrigated conditions in differentgroundnut growing zones.3. Development of simple and cheaper cropprotection technology w i t h an emphasison integrated control of the disease-pestcomplex.19

4. Demonstration of the proven research resultsthrough onfarm trials for the benefitof farmers as well as extension workers.5. Identification of the stable sources of resistanceto diseases and pests, and otherdesirable agronomic traits in the germplasm,and their use in future breedingprograms.6. Production and maintenance of a continuoussupply of breeder's seed for multiplicationinto further categories of seeds forultimate supply to the farmers.7. Resolving any other problems.The number of main and sub-centers for alloilseed crops is n o w 62. Of these, 17 aredeployed for research on the groundnut crop. Inaddition, support f r o m other centers has beenenlisted. Active cooperation of scientists in theGroundnut Program of the International CropsResearch Insitute for the Semi-Arid Tropics(ICRISAT) since the beginning of the programin 1976 has been noteworthy. Additionally, theDirectorate of Oilseeds Research derives advantagef r o m the experiences of other CoordinatedProjects (such as the Model AgronomicScheme, Dryland Farming Project, CroppingPattern and Land Use Project, and Crop Projectssuch as pulses, sorghum, millets, and sugarcanewherein oilseed crops f o r m a part of croppingpattern) and the Institute like the Central AridZone Research Institute, Jodhpur, and CentralSoil Salinity Research Institute, Karnal.The scientific strength at a main center in theNational Oilseeds Research Project normallyconsists of a breeder, agronomist, plantpathologist, entomologist, biochemist, and astatistician, while that of subcenter is limited toa breeder, or a m a x i m u m of assistant agronomistin addition.In 1979, the National Research Centre forG r o u n d n u t (NRCG) w a s established atJunagadh, w i t h a mandate to generate anddistribute breeding material at early stages andto engage in basic research w i t h a view to breakyield barriers in the groundnut crop.T h e t w o p r o c e d u r e s d e v e l o p e d f o r g r o u n d n u tresearch for various disciplines are:Four-Tier S y s t e m of TestingFor rapid multilocation testing of promisingbreeding material and to assess the material'ssuitability for different agroecological zones oradaptability at national level, each of the promisinglines enter the Initial Yield EvaluationTrials (Stage I). Depending upon performance,an entry can rise up to the National EvaluationTrial after which it is identified by the researchgroup as a potential variety. The period oftesting and promotion from one stage to thenext higher are given in Table 1.After an entry has been identified as promising,a V stage (Minikit/District Level Trial) as thefinal stage between the identification and finalrelease of the variety, has been introduced since1979.D e v e l o p m e n t of A g r o - P r o t e c t i o nTechnologyIn thedisciplines of agronomy, plant pathology,and entomology, simple to complex coordinatedexperiments are formulated and implementeduniformly at all the stations.Table 1.StageFour-tier system of testing groundnuts.Seasons of trialNo. N a m e M a x i m u m M i n i m u m RemarksIIIIIIIVInitial Yield EvaluationTrial (IYET)Preliminary VarietalTrial (PVT)Coordinated VarietalTrial (CVT)National EvaluationTrial (NET)22211121An entry f r o m IYET/PVTcan be p r o m o t e d to the nextstage after a one-season trial,if its average yield exceedsthe check variety by 25%.20

Location-specific trials under the category ofstation trials are also discussed and finalized fordifferent stations.Groundnut ResearchAchievementsThe dependence of groundnut cultivation onhighly erratic rainfall, susceptibility to devastatingpests and diseases, and the limited capacityof the groundnut grower make groundnut researchrather more challenging.Particular achievements in the groundnutprogram are:G e r m p l a s mThe groundnut program of DOR has shared itsentire collection (4968 entries) with ICRISAT(Anon. 1979), which was designated as theworld center for collection, preservation anddocumentation of the genus Arachis by theInternational Board for Plant Genetic Resources(IBPGR). The groundnut program currently hasaccess to more than 9000 accessions of theICRISAT Center.The National Research Centre for Groundnutis being developed as the second importantcenter for maintenance and evaluation ofgroundnut germplasm in the country.The program in its multilocation testing ofgermplasm/breeding material has identified alarge number of lines resistant to one or morepests/diseases. These are being evaluatedfurther in the multilocation uniform diseasenurseries (Vikram Singh 1979). The most notablefindings are listed in Table 2.Table 2. Some results of multilocation tastingof germplasm/breeding material.Source/lineG 201Ah 7724Ah 7747*EC76446Ah 7795Ah 7799Ah 7983Resistant/tolerant toLeaf spotLeaf spot, rustAphid, JassidsAphid, Leaf minerWhite grub* Also reported by R. W. Gibbons (1979).Varieties Released f o r CultivationSince 1967, some 28 varieties belonging to thethree broad growth habit groups (16 in bunch, 5in semi-spreading, and 7 in spreading type)have been released for different adaptabilityzones. Of these, M-13 and TG-1 (Vikram) are theonly t w o varieties that have been released bythe Central Variety Release Committee at nationallevel. These t w o varieties when evaluatedon farmers' fields across 3 to 5 groundnutgrowing States, on average yielded 74 and 5 1 %more than local varieties (VMA 1978).Agro-Protection TechnologyThe optimum agro-protection technology for thedifferent agroclimatic zones in respect of availablevarieties has been worked out by differentcooperating centers. Agronomic and plant protectionresearch findings have been recentlydiscussed by Singh (1979). Salient researchfindings with recent additions are:Agronomic Practicesa. Plant stand. The use of o p t i m u m seed ratesand control of seedling diseases is theeasiest and surest way to higher yields.b. Field preparation. An increase in depth ofplowing f r o m 10 cm to 30 cm has givensignificant yield increases in the red soils ofAndhra Pradesh, primarily due to increasedwater intake and increased root penetrationactivity (Table 3).c. Groundnut nutrition. Except for some areaslike the Saurashtra region of Gujarat and theKurnool district of Andhra Pradesh, wherefertilizeris being applied by farmers (in somecases much more than the recommendedlevels), the level of nutrients applied rangesfrom low to nil. Results obtained in thegroundnut program suggest higher levels ofnutrition in respect of N, P, and some minorelements (Singh 1980b). Gypsum applied at250 kg/ha has given significantly higheryields.d. Package of practices. During t h e past 2 to 3years, the relevance and effectiveness of theresearch results when applied to a largescale area has been engaging the attentionof oilseed research workers. Results f r o mmultilocation trials conducted to compare21

the recommended package of practices w i t hthe farmer's method (local) have shown thatgroundnut yields can be doubled by adoptionof the package of practices (Table 4).The significant yield increase obtained f r o mfollowing the recommended package of practicesis further confirmed by the results f r o m thedemonstration trials conducted on farmers'fields by the State Departments of Agriculture(Singh 1979), and by the results of a surveyundertaken on the causes of low yields. Thesurvey clearly showed that wherever farmersadopted recommended practices (not in full),the district average groundnut yields have been4100 kg/ha as against the average yield of1000 to 1100 kg/ha where farmers did not adoptthe recommended practices (Reddy and Reddi1979).Protection-TechnologyLarge reductions in yield due to attacks bydiseases and pests rank second only to thereductions due to unfavorable weather.Due to the unavailability of resistant/tolerantvarieties to major diseases and pests and keepingin mind the limited investment capacity ofthe farmer, the Project from the very beginninghas emphasized the development of relativelysimple and cheaper control measures. Controlmeasures for all the important diseases andpests i.e., leaf spots (both early and late),groundnut rust, various rots, and aphid, leafminer and white grub have been determined.At current prices, most of the control measures(operational cost included) cost less thanRs.150/ha and have resulted in significant yieldTable 3.Effect of depth of plowing on groundnut yields in the rod soils of Andhra Pradesh. a Yield inquintals/ha (1q = 100 kg).Treat. yearResidual effectsPlowing 1972 1973 1974 1975Shallow (10 cm)Deep (30 cm)CD4.25.42.18.611.72.25.78.22.113.314.2NSa. Data from Dryland Farming Project.Table 4. Average yield response of two groundnut varieties under different management practicesat Ludhlana (Directorate of Oilseeds Research 1980).Pod yield (kg/ha) b% Increase % IncreaseTreatment M-13 over (A) PG-1 over (A)(A) Local practices 1058.33 974.67(B) Recommended package of practices 2468.33 133.23 2313.00 137.31(C) B minus seed treatment and 2130.00 101.26 2057.00 111.05termite control(D) B at 75% seed rate 2302.00 117.51 2132.00 118.74(E) B minus fertilizers 1964.33 85.61 1872.33 92.10(F) B minus weed control 1667.00 57.51 1815.33 86.25(G) B minus protective irrigation 1645.67 55.50 1770.67 81.67(H) B minus plant protection 2074.67 96.03 1699.33 74.35(I) B but less duration b 1838.67 73.73 1939.67 99.01a. Average of three kharif season trials (1977-79).b. The crop was harvested 15 and 20 days earlier than the normal harvest time for M-13 and PG-1, respectively, in order to vacatethe field for next crop.22

increases and a net return of more thanRs. 400/ha. Controlling white grub costsRs. 280/ha, but the yield increase is more than100%. Net returns in the case of rust controlhave ranged f r o m Rs. 200 to 370/ha.O t h e r N o t a b l e AspectsAttempts at hybridization in groundnut in thepast have had a very l o w success rate (about10%). This has now largely been overcome andthe success rate has increased to more than50%, and sometimes it has been over 80%.Some success towards identification of thesuccessful one f r o m the accidentally selfed one,on the basis of pod morphology, has been made(Raman 1980). However, successful fertilizationof both the proximal and distal ovules has notbeen accomplished in all cases.The higher success rate of hybridization hashelped to achieve a long overdue project mandate,i.e., free exchange and flow of groundnutbreeding material. The large scale exchange ofbreeding material for the first time was accomplishedin the 1979 groundnut season,wherein the contribution from the ICRISATGroundnut Program was largest.The Future StrategyThe research goal is stabilized groundnut productionin the country. Fortunately, the nationalresearch infrastructure already developed forthe groundnut program, reinforced by the t w odevelopments in the recent past — i.e., theestablishment of the Groundnut Program atICRISAT, Hyderabad, in 1976 and the establishmentof the National Research Centre forGroundnut at Junagadh (Gujarat) in 1979 —has the capacity to meet the future challenges.What is required n o w is reorganization andreallocation of priorities, and the strengtheningof weak links in the program.It is believed that these could be achieved by:1. Identification of regional/national problemsof a short and long-term nature; thefixing of priorities and assignment thereofto specific worker(s)/center(s) as againstthe present practice of everyone workingon each and every problem.2. Identification of centers and strengtheningthereof, for the generation and early sharingof breeding material having desirabletraits like disease and pest resistance,drought tolerance, early or late maturitygroups, and interspecific hybridization.3. Strengthening and development of programsin plant pathology and entomologywith emphasis on identification of sourcesof stable resistance to various pests,immuno-genetic studies, eco-biology ofthe pest, integrated pest/disease managementand prognosis of diseases andpests of economic importance.4. Establishment of a center for intensificationof research in all disciplines for irrigatedgroundnuts — an aspect hithertonot covered in the national groundnutprogram.5. Strengthening and development of researchin plant physiology and microbiology.NRCG (Junagadh) and ICRISAT havebeen identified as the main centers forthese t w o programs.6. Identification of centers for intensivestudies on groundnut yield-weather relationships;detailed and in-depth studies onmicronutrient-nutrition of the groundnutcrop; and nitrogen nutrition of groundnutin relation to rhizobial inoculation andvarieties.7. Introduction of compulsory on-the-farmtrial programs at each center.8. Standards and measures to improve thequality of experiments and therefore thevalidity of results.Many of the basic studies are being carriedout and will be carried out in the future atICRISAT, f r o m which the national program hasderived/will derive advantage. The existing relationshipbetween the national groundnutprogram and the ICRISAT groundnut programis very close and cooperative. It is hoped thatboth will benefit f r o m each other and the resultsthat flow from such joint efforts will benefit theultimate consumer — the groundnut grower.ReferencesA N O N . 1979. The current status of groundnutgermplasm at ICRISAT. Paper circulated to m e m -23

ers of IBPGR/ICRISAT ad-hoc Working Group onGroundnut G e r m p l a s m , at the Group Meeting atICRISAT, Hyderabad, 2 4 - 2 6 Sept 1979. ( M i m e oICRISAT) 21 pp.G I B B O N S , R. W. 1980. Groundnut i m p r o v e m e n t researchtechnology for the semi-arid tropics. Pages27-37 in Proceedings of the Inaugural S y m p o s i u mon Development and Transfer of Technology f o r theRainfed Agriculture and SAT Farmer, 28 Aug-1 Sept1979, ICRISAT, Patancheru, A.P., India.R A M A N , V. S. 1980. A note on g r o u n d n u t hybr i d i z a t i o n — p e r c e n t a g e of success and Identificationof crossed pod. (Personal c o m m u n i c a t i o n ,4 August 1980).REDOI, G. H. S., and REDOY, A. D. 1979. A survey reportof causes of l o w g r o u n d n u t yield in six districts ofA n d h r a Pradesh. A P A U , Rajendranagar, Hyderabad.77 pp.S I N G H , V I K R A M . 1978. Directorate of Oilseeds Research,its objectives, organization and future planof w o r k , (DOR mimeo) 21 pp.S I N G H , V I K R A M . 1979. Current status of oilseeds researchin India, presented at national seminar onresearch and development strategies for oilseedproduction in India, IARI, N e w Delhi, 7 - 1 0 Nov 1979.(DOR M i m e o ) . 65 pp.S I N G H , V I K R A M . 1980a. Development of agricultureresearch in India w i t h special reference to coordinatedmulti-disciplinary approach. Lecture deliveredto the ARS Probationers, NAARM, Hyderabad,Feb 1980.S I N G H , V I K R A M . 1980b. A g r o n o m i c potential of oilseedcrops. Lecture delivered to FAI Executive Trainees atVikram Hotel, New Delhi, 5 April 1980. (FAI Mimeo)27 pp.V M A . 1978. Annual report of the research and developmentw o r k d o n e by the Vanaspati Manufacturers'Association of India, Bombay.24

Role and Function of the IRHOin Groundnut Research and DevelopmentP. Gillier*StructuresThe IRHO is a private nonprofit organizationsponsored by the French Government and incorporatedinto the GARDAT (Study and ResearchGroup for the Development of TropicalAgronomy).Its head office is in Paris, where the GeneralDirectorate, Research Department, and thePlant and Technology Departments (oil palm,coconut and annual oil crops) are also located.The scientific departments and laboratoriesare at Montpellier. They coordinate the outsideactivities which are carried out in various formsin the tropical zone.This structure is assisted by a Documentationand Publication Department, which distributesin 75 countries in French, English, and Spanish amonthly review called OLEAGINEUX whichspecializes in oil crops.Objectives and ActionThe IRHO is devoted to the development oftropical oil plants. It deals w i t h the oil palm,coconut, and annual oil crops in the frameworkof international cooperation. Its activities rangefrom scientific research to the practical applicationof its results. It contributes to technical andeconomic promotions in the countries concerned.The technical aid and assistance made availableby IRHO is solidly based on experienceacquired in the tropical zone in numerous researchstations, plantations and oil mills inmore than thirty countries for over thirty years.* Director, Annual Oil Crops Department, IRHO, (Inst i t u t d e R e c h e r c h e p u r les H u i l e s e tOleagineux — Research Institute for Oil and Oilseeds).11 Square Petrarque, 7501L, Paris, France.Means of Interventionand ResourcesThe IRHO can call on 85 technical executives(scientists and research workers) covering avery wide range of disciplines: pedology, ecology,genetics, cytology, physiology, chemistryand biochemistry, agronomy, phytopathology,virology, entomology, statistics and softwaretechnology and economics; this does not includethe administrative executives, Plantationand Project Directors, and extension workers.The IRHO can intervene in many areas, includingagronomic research in the strict sense(conception, control and interpretation of experiments);specialized studies in pedology,climatology, mineral nutrition, phytosanitarytreatments; creation of new varieties and supplyof selected seeds; contributing to designingdevelopment plans; technical control of plantations;advice and control in building and operatingoil mills; specialization of scientists; andpre-extension work on techniques developed inthe stations, in rural areas.These interventions occur in the frameworkof general cooperation agreements existingbetween the French Government and othercountries (in general, Francophone Africancountries) in the framework of a private agreementbetween the IRHO and the governmentconcerned, or in the framework of private contractsbetween the IRHO and various researchor development bodies, or international organizations.In 1980, for a budget of US$ 16.5 million, abreakdown of the origin of the credits is: fromFrench governmental organizations, 25%; fromforeign beneficiary states, other states and internationalorganizations, 12%; and the lRHO'sown resources and private credits, 63%.Created immediately after the war, the IRHOonly began to work on annual oil crops, and onthe groundnut in particular, in 1948. The Insti-25

tute has thus been working for exactly 32 yearson these plants in the Mediterranean area.Certain basic techniques were created there inthe laboratory (leaf diagnosis, growth measurementsetc) and then in West and CentralAfrica. We are n o w moving into Southern Africaand other countries that have demonstrated aninterest.Groundnut and annual oil crops representonly 2 0 % of the IRHO's activities. The basicframework of our interventions in this area, andwhere they now stand are described below:Conditions for interventionand LocalizationThe Annual Oil Crops Department is working onthe groundnut almost exclusively in FrancophoneAfrica. Before these states becameindependent, the Department had its own researchstations, or specialised sections, in variouscountries and took part in the generalagronomic research effort in this area. At thattime, this was coordinated on the level of theAOF and AEF federations.A f t e r i n d e p e n d e n c e , r e v i s i o n o f t h earrangements lent the various interventions amore national character; coordination of thevarious arrangements was lessened. Fortunately,present relations between states, andprivileged links between the research workersthemselves, have to a great extent preventedthe same work being done twice over.The IRHO has pursued its activities in theareas of applied agronomic research, preextensionwork and seed multiplication. Thelatter t w o activities are essentially linked toapplying research results. To date, we operatein six countries: Senegal, Mali, Guinea Bissau,Upper Volta, Niger, Tchad.Depending on the situations, the work to becarried out, and the type of contract signed, theresearch workers or technical advisors are assignedto precise programs or projects. Therearethus many methods of work. For example, insome cases only the research workers' salariesa n d transport expenses to the work site arecovered by the IRHO; the host governmentensures the w h o l e operation. In other cases, thesalary a n d operation are entirely at the expenseof the IRHO w h i c h manages the program or theoperation.For a company or government, the advantagein working with our Institute stems mainly f r o mthe support and logistical backup which theisolated agent on a station or the technicaladvisor assigned to a specific operation canreceive, as well as the rather considerable rangeof oil crop scientists or technicians available tohelp solve their problems.Although the staff of the Annual Oil CropsDepartment numbers only about 20 scientistsand technicians, the IRHO tries to satisfy allrequests in function of the states' requirements.It answers calls for tenders for thesupply of services in its area, and ensures acertain number of study, technical advice orconsultant missions throughout the w o r l d .Range of ActivitiesSome of the past or present activities pursuedby our agents in the framework of contracts oragreements are described below. In most cases,they are not exclusive to the IRHO, as they arepart of ateam undertaking, butourparticipationis often essential, and justifies our claimingthem as part of our knowledge, and a result ofour experience.ResearchPhysiologyFrom 1956, systematic work has been pursuedon groundnut drought resistance, its precisemeasurement, evaluation of sensitivity stages,and development of rapid tests enabling preciseevaluation of the plants' reactions to waterstress. This aspect of research conducted inBenin and Senegal was mainly designed toenable practical sorting and selection to bedone on progenies, bulks or populations, and tobetter evaluate the intrinsic value of choices.At present, we have in-depth knowledge ofthe plant in this particular field,.authorizingjudicious manipulations. This can eventuallyserve other species with similar characteristics.Mineral NutritionFrom 1948, the first work d o n e by the IRHO ongroundnut dealt w i t h the plant's mineral nutrition.The groundnut was then considered to be26

AppendixList of countries where IRHO has been operatingfor the last 15 years on a long-term basis(**), on a short-term basis at present (o), or as aconsultant (*).West Africa(o) Benin:Castor research; consultancy for a developmentproject (SONACO); yearly support fordirecting agricultural research (groundnut,castor).(**) Chad:Study of the participation in the integrateddevelopment project of southern Chad(groundnut, cotton); groundnut seed multiplicationand experiments.(*) Gambia:Study for restructuring the groundnut sectorincluding production and industrialization.(**) Guinea Bissau:Participation in scientific research and developmentactivities for the Mancara Project;experiments; seed multiplication and otherstudies.(»*) Mali:Scientific research on groundnut, sesame,and soybean; technical advice to OACV;technical assistance for groundnut seed multiplicationand storage; technical assistanceand services offered for the construction andoperation of a confectionery groundnut processingunit.(**) Niger:Participation in scientific research ongroundnut and sesame; technical assistancefor organizing seed multiplication operationsin Zinder, Maradi, and Dosso; periodic consultationfor improving groundnut production.(*) Nigeria:Study of the possibilities of a cash crop(groundnut) rehabilitation project in thenorth; study of a groundnut seed multiplicationunit in the State of Kano.(**) Senegal:Participation in ISRA's research work ongroundnut; technical assistance for confectionerygroundnut production; technical assistancefor the establishment and operationof a national seed service; study of theagroindustrial channels for confectionerygroundnut.(*) Sierra Leone:Study of the possibilities of the groundnutsection in the northern development project(IBRD).(*) Togo:Study of the groundnut section of the developmentproject in the maritime zone(IBRD).(**) Upper Volta:Scientific research on groundnut, sesame,soybean, and shea butter trees; researchstation marragement; seed multiplication;extension sector management.Central Africa(*) Cameroon:General oilseed crops study.(o) People's Republic of the Congo-:Agricultural research on groundnut; seed multiplication;consultancy forthe development ofannual oilseed crops.(o) Central African Republic:Agricultural research on annual oilseed cropsand study of a development project.(o) Gabon:Agricultural research on groundnut; study of adevelopment project in the plateau region.East Africa(*) Mozambique:Consultancy for the plantation societies andthe government.Southern Africa(*) Botswana:29

Changes in the research and developmentrequirements of groundnut.(*) Zambia:Technical support for planning a groundnutprocessing unit.Indian Ocean(*) Madagascar:Mission for assessing oilseed requirementsand the development plan; assistance to acastor project for genetic studies.Central and South America(*) Dominican Republic:Consultancy for groundnut development.(*) Haiti:Consultancy for the development of annualoilseed crops.(*) Mexico:Mission for identifying and studying the possibilitiesof groundnut and soybean projectson the east coast of Mexico for the PlanNacional Hydraulico, and IBRD.Far East(*) Indonesia:Consultancy for improving castor production.O c e a n i a(**) New Hebrides:Groundnut research and experiments.30

Peanut Collaborative Research SupportProgram PlanningC. R. Jackson and D. G. C u m m i n s *Our purpose at this Workshop is to inform y o uof the Peanut Collaborative Research SupportProgram Planning (CRSPP) effort. The collaborativeconcept is a new USAID researchprogram in addition to other existing research,and is designed to aid research on a globalbasis. The planning is supported through agrant f r o m USAID to the University of Georgia,made under provisions of the Title XII programof the U.S. Board for International Food andAgricultural Development (BIFAD). The planningoffice is located at the Georgia ExperimentStation, Experiment, Georgia, which is veryfitting since much of the modern peanut researchoriginated at this station.The planning grant was awarded on August12, effective August 1,1980 and will extend overan 18 month period. Curtis R. Jackson, PlanningDirector, and David G. Cummins, AssociatePlanning Director, will be responsible for activitiesunder the grant. Robert Jackson, DS/AGR, is the AID Project Manager.The Collaborative Research Support Program(CRSP) concept is new to many of us. It is anarrangement which facilitates long-term collaborativeresearch among U.S. universities,the U.S. Department of Agriculture, U.S. Departmentof Commerce, International AgriculturalResearch Centers, other research institutions,and developing country research institutions.Collaborative research embodies theidea of working jointly in a research endeavor.Funds and benefits flow primarily to the developingcountries, and the research is done inthe developing countries themselves, to them a x i m u m extent practicable.The primary goal of the CRSP is to develop a* Planning Director, and Associate Planning Director,respectively, Peanut CRSP, University of Georgia,Georgia Experiment Station, Experiment, Georgia30212, USA.structure through which scientific talent andresources of the USA, not available in developingcountries, can c o m e t o bear on food production,distribution, storage, marketing, and consumptionproblems in developing countries.The CRSP approach will link institutions (andindividuals) having c o m m o n interests in organizedresearch programs on selected problems.The CRSP is built upon existing researchprograms in developing countries. Developingcountry institutions would participate out of asense of priority research needs and their capabilityto contribute to a solution of the priorityresearch problems.The CRSP is unique in providing the linkagebetween the U.S. and developing country institutions,and in that the program must maintaina university identity.We, as the planning group, are interested incontact with interested individuals f r o m thepeanut-producing countries around the world.Our primary goals relative to developing countrieswill be to determine constraints to peanutproduction and utilization, assess interest inparticipation in a CRSP, evaluate researchcapability and resources, and to improve ourknowledge of peanut research and production,and utilization.D u r i n g t h e f a l l and winter of 1 9 8 0 - 8 1 , we willbe involved in site visits and other activities todetermine country interests, develop the stateof the art information, and identify constraintsto peanut production and utilization. In the earlysummer of 1981, preproposals will be solicitedfrom U.S. universities and other research institutionsto determine interest in collaborativeresearch programs to relieve these constraints.A selection process with the aid of a TechnicalPanel will later result in full research proposals,establishment of U.S. and developing countryinstitutional linkages, and final project development.The planning process is scheduledfor 18 months, concluding January 3 1 , 1982.31

A newsletter highlighting planning activitieswill be published periodically during t h e courseof the project. Any inquiries of interest in thenewsletter or anything else concerning theproject should be directed to Dr. Curtis R.Jackson, Planning Director, or Dr. David GCummins, Associate Planning Director, Universityof Georgia, Georgia Experiment Station,Experiment, Georgia 30212, USA, Telephone404-228-7312.32

Research and Extension Inputs Resultingin High Yields of Groundnuts in the USARay O. H a m m o n s *The groundnut, Arachis hypogaea L., is animportant economic farm crop in the UnitedStates. Ninety eight percent of the commercialproduction is in seven states — t w o on themid-Atlantic coast, three in the Southeast, andt w o in the Southwest. Most of this area is arelatively humid zone although some of theSouthwest crop is g r o w n under semi-arid f a r m -ing.Groundnuts rank ninth in area a m o n g theUSA r o w crops and second in dollar value perhectare. In 1979 the harvested crop area was617 400 ha, w i t h a production of 1805 000metric tons (MT), averaging 2925 kg/ha.Since the major thrust of this paper focuseson production inputs in Georgia, the leadinggroundnut state, the following productionstatistics show the current level of technologyachieved there. In 1979, Georgia farmers produced763 000 MT on 213 450 ha, for an averageof 3576 kg/ha. The crop value at the farm levelwas S360 000 000. In Georgia, groundnuts werethe No. 1 crop enterprise accounting for 12.1%of the state's cash farm receipts.This efficiency level can be attributed totechnology developed by research and transferredto the farmer by an effective agriculturalextension service. Since these major developmentsoccurred during the past 2 5 - 3 0 years, letme describe the situation then as a frameworkagainst which the production advances willgain perspective.Thirty years ago, the land was prepared withthe m o l d board p l o w and a spike tooth harrow,and seed was planted in a slight f u r r o w using asingle row walking planter. The plants werecultivated and hoed 3 or 4 times. Plant protec-* Supervisory Research Geneticist and ResearchLeader — Crops, the United States Department ofA griculture, Science and Education A d m i n i s t r a -t i o n , Agricultural Research, Southeast Area, at theUniversity of Georgia Coastal Plain Station, Tifton,Georgia 31793, USA.tion consisted primarily of an application ofcopper-sulphate dust for leaf spot. A longseasoncultivar was grown and harvesting wasusually begun when the leaves shed. Landpreparation, cultural practices, and the liftingoperation were done with animal-drawnequipment. When the plants were lifted theywere stacked around a pole to field cure. After 6weeks or more, the stacks were moved to astationary mechanical picker w h e r e thegroundnuts were removed f r o m the vines. Thissystem of production was labor intensive, requiringabout 185 hr/ha. Yields averaged under900 kg/ha (McGill 1979).Little research and extension effort wasapplied to the crop. Some cultivar improvement,row and drill spacing studies, and thecopper-sulfur leaf spot fungicide work formedthe technology information bank. Neverthelessfarmers f r o m six Southwestern Georgia counties,meeting in January 1950, attracted theattention of the state's leading newspaper bysetting a goal of a "half ton per acre", or 1120kg/ha. As marginal land went out of productionand growers began to try the new technology,the Georgia goal was reached in the 1956season.Cultural practices in the middle 1950's werepoor by modern standards but were the bestthen known. Weeds were controlled by plowingas close as possible to the drill, hoeing, anddirting to smother other weeds.Many farmers grew established landrace cultivars,with relatively low yielding potential, andkept their o w n seed or purchased it f r o m aneighbor or a sheller-seedsman. In the latterinstance, Thiram ® (Arasan ® ) was usuallyapplied as a protective fungicide.Adaptive cultivars were developed mainly byline selection from farmers' stocks or by screeningthe limited stocks of exotic introductions,although the first series of cultivars developedby selection following hybridization were alsobecoming available. By 1960, farmers in the33

Southeast had the choice of a number of cultivarsdeveloped by public breeders in StateAgricultural Experiment Stations and the U.SDepartment of Agriculture.Since there were consumer products utilizingthe major morphological groups of peanuts,growers had the option of g r o w i n g one or moreof the three USA market types and more thanone cultivar of each type:S P A N I S H . Small Spanish, Dixie Spanish, GFASpanish, Argentine, Spantex, and Spanette.R U N N E R . Dixie Runner, Early Runner, FlorispanRunner, Southeastern Runner 5 6 - 1 5 , and VirginiaBunch 67.VIRGINIA. Georgia 119-20, Virginia Bunch G2,Virginia Runner G26, NC 2, and Virginia 56R.Results of uniform variety tests, reorganizedafter 1955 to provide comparative performancesa m o n g cultivars and advanced breedinglines within market types, were widelypublicized. These data gave the farmer a rationalchoice of cultivars to use in his farmingsystem.The framework of cultivars adapted to the soiland climatic features of the area provided asuitable backdrop for a number of breakthroughsin groundnuts research and development.It is not my purpose h e r e t o provide a fullchronology of these events since many of theachievements were interwoven together intothe production package.The highlights of research technology andextension inputs which have led to high yieldlevels in the Southeastern United States may beoutlined as follows:Shaker-windrowerand CombineThe first major advance was in equipmenttechnology. Groundnuts had emerged as acommercially valuable crop with the developmentof the stationary picker in 1905 butalthough horses, stationary engines, and eventuallytractors were used to power thesemachines, very little improvement in pickingefficiency had occurred in 40 odd years.T w o pieces of equipment developed inthe late 1940's revolutionized harvesting practices.One was a shaker-windrower, w h i c hpicked up the groundnuts after they were dug,shook out the soil, and formed t w o adjacentrows into a random w i n d r o w for curing. Thiseliminated the stacking practice (Mills andSamples 1973). Then in 1948-50, J. L.Shepherd and W. D. Kinney developed a onceovermobile peanut combine in research atTifton. These two innovations, quickly adopted,cut the harvest labor requirement by about85%. They also led to the development ofartificial drying principles used initially at buyingstations, but soon adopted as an on-thefarmpractice.Tillage Methodsfor Disease ControlThe second major advance was the developmentof tillage methods for nonchemical diseasecontrol. The practice of deep plowing, followedby shallow, nondirting cultivation, formed thebasis of the suppression of the white moldcaused by Sclerotium rolfsii. L. W. Boyle andCO-workers (Boyle, 1958; Boyle and Hammons,1956) developed concepts, confirmed by a largebody of experimental evidence, on the benefitsof deep turning to bury surface organic matter.Selective HerbicidesThe third major breakthrough came with thediscovery of selective herbicides for weed control.L. W. Boyle, E. W. Hauser and associates atthe Georgia Agricultural Experiment Stationdeveloped a new scheme of culture throughresearch to lay the foundation for gains in yieldand crop quality and allowed farmers to use thegenetic improvements bred into the newercultivars.About 1959, Hauser led the pioneeringstudies showing that herbicide mixtures,applied at the ground cracking stage of seedlingemergence, were more effective than the componentsof such mixtures. These results todaystill form an essential component of weedcontrol systems for groundnuts (and othercrops).P r e c i s i o n L a n d P r e p a r a t i o nThe fourth step was provided by J. L Shepherd34

i.e., engineering innovations in precision landp r e p a r a t i o n tactics t o m a x i m i z e t h epathologic-agronomic practices and precisionplanting to optimize plant populations.Organization of PeanutExtension ProgramThe University of Georgia established the positionof Extension Agronomist — Groundnuts,in the Cooperative Extension Service in 1959when J. Frank McGill undertook this work. Thepathological, agronomic, and engineering principlesdescribed above were unified into apackage approach for use. This package oftechnology, carried through the County AgriculturalAgents, was quickly adopted.Since 1959 the Extension Specialists team,located in the heart of the peanut belt at Tifton,has increased to six: t w o in agronomy and oneeach in engineering, entomology, plant pathology,and weed control. The significance of thisteam lies not only in their skills in transmittinguseful and timely research information directlyto farmers and/or through the County AgriculturalAgents, but also in their function to relaythe farmers' needs and problems back to theresearchers.Research/EducationPlanning ConferencesIn the late 1950's the University of Georgia andcooperating USDA scientists organized a conferenceof workers engaged in groundnut researchand education. This group has metannually w i t h administrators in planning sessionswhich systematically identified problemareas, discussed recent progress, and recommendednew approaches and personnelrequirements. This conference provided an updatingof key production constraints, a crossfertilizationof ideas, and an' opportunity forshifting research responsibilities and resourcestoward solving new or difficult problems.Growers Support Researchand ExtensionA different kind of activity that has stimulatedgroundnut production in Georgia followed theorganization in 1961 of the Georgia AgriculturalCommodity Commission for Peanuts (thePeanutCommission). This grower group, usinga self assessment of $1 per t o n since 1961 (and$2 more recently), has generously supportedgroundnut research at Georgia's three agriculturalresearch facilities, has strengthened theextension specialist program and has sponsoredgraduate research fellowship grants. Thissupport equalled $2.5 million f r o m its initiationuntil June 1980 and is continuing. The Commissionregularly publishes a groundnut magazine,which is.circulated to all growers in Georgia,Florida, and Alabama (where more than 60% ofthe crop is grown). It provides a readily availablemedium for the rapid transfer of newtechnology to small scale farmers as well astheir more favored neighbors.Effective Seed DressingsOther significant research achievements cameduring the 1960's. The development by C. R.Jackson and D. K. Bell of seed dressings usingorganomercurials significantly improved standsby virtually eliminating Aspergillus Crown Rot,the No. 1 seedling disease. After the removal ofthe mercurials by the Environmental ProtectionAgency, effective organic fungicide c o m -binations developed by Bell have served as areliable replacement.Subsurface HerbicideIncorporationIn the early to mid-1960's Hauser developeddevices and methods for the subsurface incorporationof the herbicide vernolate ®. The newsubsurface treatments enabled fanners to controlannual weeds and nutsedge more effectively(and w i t h better crop tolerance)than with the previous methods of application.IrrigationThe next major step came with the documentationby Engineers L. E. Samples and J. L.Stansell in 1965-68 of the magnitude of yieldand quality responses due to groundnut irrigationin the Southeast. In this area the sandy35

soils, rolling topography, fluctuating rainfall,and high cash value of the crop have led to theuse of sprinkler systems for growing irrigatedgroundnuts. Research and on-farm test datashowing a 1 0 - 1 8 % increased average yield,and frequent drought stress, led to a widespreadadoption of the new technology. From 7.5% ofthe Georgia groundnut crop area irrigated in1970, the practice escalated to 23% by 1975, andto 4 8 % in 1979. For 1980, a year of severedrought and heat stress, the estimate is 54%.In Georgia, entomological research by L. W.Morgan and associates about 1970 showed thatthe systematic use of insecticides eliminatedbeneficial insects, thereby increasing t h e totalpest problem and population costs. As a directresult of this research, an insect pest managementprogram was initiated in 1972 and theservice n o w includes almost one-fifth of Georgia'scrop area. This program is based upon theprinciple that insects must be at economiclevels before control measures are justified.That is, the loss in yield or quality attributable toinsect damage must exceed the cost of control.The program is voluntary by the growers andrequires trained insect scouts w h o regularlycheck fields to monitor insect levels. Growersadopting the program have greatly reduced thenumber of insecticide applications (Informationcourtesy of L Morgan, H. Womack & R. Lynch).Variety ShiftsAlthough a dozen groundnut cultivars weregrown in Georgia in the late 1950's, t w o werepredominant. The Runner market type accountedfor 55% of ail production area and DixieRunner alone for 34%. Spanish type occupied4 1 % of the area, w i t h Dixie Spanish on 24%.Virginia type accounted for less than 4 % .The widespread availability of newer cultivarswhich responded well to the improvedtechnology influenced a marked shift by growers.As the Argentine and Starr cultivars replacedDixie Spanish, Spanish-type productionmoved to more than one-half the Georgia area.Even though the Early Runner cultivar replacedDixie Runner, the total area in Runner typedeclined to about 4 0 % by 1969.The startling change was the rapid rise inproduction of Virginia type groundnuts, whichmoved f r o m 3% in 1959 to 14% in 1969. Thischange was influenced by a newly availablecultivar, Florigiant, and by a price structurefavoring the larger seeded Virginia type.The decade of the 1970's was a time for theintegration of many research and extensioninputs resulting in high yields of groundnuts inthe United States.Insect ScoutsBroadleaf Weed ControlWeed scientists in Georgia and Alabama cooperatedin showing that the groundnut planteffectively suppresses certain broadleaf weedspecies when the crop is maintained weedfreefor 5 - 6 weeks after they emerge. These results,combined w i t h subsequent r o w spacingstudies, increased the understanding of thecompetitive capacity of the peanut plant andenabled farmers to better plan their weed controlstrategies for more efficient and moreeconomic production. More recent and currentresearch indicates that weed weights may bereduced by up to 50% and the yield ofgroundnuts increased by 10% or more simplyby manipulating r o w spacing (Informationcourtesy of E. W. Hauser and G. Buchanan).The Florunner CultivarThe most significant input of production researchtechnology to high yield performance inthe USA was the release of the Florunnergroundnut cultivar in 1969 and its acceptanceby growers and the industry. Research anddevelopment of Florunner was conducted at theFlorida Agricultural Experiment Station and thebreeding methodology in use there will bediscussed by A. J. Norden (this conference). Myconcern here is to describe some of the impactas other research inputs were meshed with theFlorunner cultivar in the production package.At the time of its release, Florunner had beenevaluated in cultivar performance trials inFlorida, Georgia, and Alabama, where itperformed well across a w i d e range of soil andclimatic conditions, excluding p r o l o n g e ddrought.36

Florunner is a product of a broadbased,open-ended breeding program that producesmultiline groundnut cultivars w i t h greatergenetic diversity than the pure line cultivarsthey replaced (Norden 1980; Hammons 1976).At the time of its release, Florunner outyieldedits predecessor Early Runner by about 20%. By1979 it was grown on 98% of the peanut croparea in the Southeast and occupied some 64%of the total crop area in the nation (Hammons,unpublished survey data).O r g a n i c F u n g i c i d e sPrior to 1970 almost ail of the groundnut farmersused copper-sulfur dusts for controllingleaf spots. With the discovery of the systemicfungicide benomyl (Benlate ® ) , and a protectivefungicide chlorothalonil (Bravo ® ) , control ofleaf spot was significantly improved and yieldlosses from early defoliation were sharply reduced.These organic fungicides came on theheels of the introduction of Florunner and theiruse lengthened the fruiting period by up to 2weeks (Information courtesy of R. H. Littrell).The increasing use of irrigation systems providedadditional water to support the extraproduction when natural rainfall was sparse.F u n g i c i d e - t o l e r a n t S t r a i n sThe widespread and extensive use of benomylresulted in sel ection of strains of the Cercosporaand Cercosporidium leaf spotting fungi that wasunparalleled in the use of fungicides for diseasecontrol. Research pathologists in Alabama andGeorgia almost simultaneously discoveredstrains of these fungi tolerant (resistant) to thisotherwise highly effective fungicide. Tolerantstrains were found in 1973 using laboratorytechniques before economic losses occurredunder field conditions.In Georgia, R. H. Littrell, using laboratory andgreenhouse experiments, proved that benomyltolerantstrains survived and were capable ofcausing disease. Based upon these results, thefungicide was removed f r o m the list recommendedfor 1974. Research data in 1974 indicatedbenomyl was completely ineffective, andyield in benomyl-treated plots did not differf r o m that in the untreated controls. Shouldbenomyl have been used in 1974, dramaticlosses f r o m foliar diseases w o u l d have occurred(Littrell 1974 and personal communication1980; Smith and Littrell 1980).A P a c k a g e A p p r o a c hBy the middle of the 1970's the original packageof production technology (McGill and Samples1969) had been modified (McGill et al. 1973) toincorporate new discoveries. Further finetuningof the principles provides the frameworkfor farmers in Georgia in the 1980's (Henning etal. 1979).C u l t i v a r / l n s e c t i c i d e I n t e r a c t i o nAn additional input in the area of herbicideapplication is an example of further research tooptimize the yield potential of the crop. E. W.Hauser led a three-state team that evaluated thegenetic vulnerability of groundnuts to intensifiedpesticide treatments. They found that theyield of Florunner was significantly increasedmost of the time by the insecticide disulfotan (afinding which surprised entomologists). An u n -derstanding of these cultivar/insecticide interactionswill enable groundnut farmers tomore logically devise pesticide sequences foreffective pest control (personal communication,E. W. Hauser 1980).F u n g i c i d e / N e m a t o c i d eC o m b i n a t i o nIn a similar manner, Pathologist S. S.Thompson led a team in demonstrating thebenefits of the soil fungicide PCNB in combinationwith a nematocide (Mocap ® or Oasinit ®)in suppressing the white m o l d fungus S. rolfsii.Other major and minor advances in agronomy,engineering, pathology, entomology,and other disciplines have contributed substantivelyto the production package. Time will notpermit my discussing many of these. A m o n gthose which may be listed are:1. Improved agronomic practices, includingbalanced fertility of major and minor nutrientsapplied following soil test recommendations,precision liming, and the ex-37

tensive use of gypsum (CaSC4) on Runnerand Virginia type peanuts.2. W i n d r o w inverters to shorten exposure ofthe dug crop to potentially adverseweather and thus reduce losses in combining.3. Availability and general use of effectivepesticides which reduce mechanical contactwith plants, provide season-long controlof insects and foliar diseases, and givemoderate control of soil-borne diseasesand nematodes.4. Increasing use of some form of solid-setirrigation system to provide adequate soilmoisture upon demand.5. Finally, and perhaps of greatest importance,is the improved educational level offarmers w i t h their greater awareness ofthe value and impact of agricultural research.Farmers, n o w more than ever because ofsharply escalated costs, are willing to incorporateeffective and timely research results intocommercial production practices. This evolvinggrower attitude has had a very positive effect onthe entire crop management program, particularlyin the southeastern peanut belt.Actually, w i t h recent emphasis by the publicresearch sector on applied as contrasted withbasic research, and the rapid assimilation ofresults by growers, the stockpile of unusedtechnology is less extensive than it formerlywas.The examples of cooperative interactions betweenresearchers and their linkages with amultidiscipline extension team as described inthis paper have shown that this approach isbetter than that of an individual alone trying tosolve a myriad of problems.ReferencesBOYLE, L. W. 1958. Fundamental concepts in the developmentof control measures for southern blightand root rot on peanuts. Plant Disease Reporter40: 661-665.BOYLE, L. W., and H A M M O N S , R. O. Cultural Practicesw i t h respect to peanut yields and control ofsouthern blight and root rot. University of GeorgiaAgriculture Experiment Station.Mimeograph 3 1 . 12PP-H A M M O N S , Ray O. 1976. Peanuts: Genetic vulnerabilityand breeding strategy. Crop Science 16: 5 2 7 -530.H E N N I N G , R. J., M C G I L L , J. E., S A M P L E S , L. E., S W A N N ,C , T H O M P S O N , S. S., and W O M A C K , H. 1979. G r o w i n gpeanuts in Georgia: A package approach. CooperativeExtension Service, University of Gerogia Bulletin640 (Revised). 48 pp.LITTRELL, R. H. 1974. Tolerance in Cercosporaarachidicola to b e n o m y l and related fungicides.Phytopathology 64: 1377-1378.M C G I L L , J. FRANK. 1979. Forty years of policy impacton the family peanut f a r m . Prepared at the requestof the (U.S.) Senate Agricultural Committee, Pages1-30, plus 8 appendix pages.M C G I L L , J. F. 1980. Early 1950's research reshapedpeanut farming. Southeast Farm Press 7(13): 12.M C G I L L , J. F. 1980. Phenomenal peanut yield increasesrecorded in first half of 70's decade. SoutheastFarm Press 7(14): 12.M C G I L L . J . F . , H E N N I N G , R . J . . S A M P L E S , L.E., FRENCH, J .C, and T H O M P S O N , S. S. 1973. Growing peanuts inGeorgia: A package approach. Cooperative ExtensionService, University of Georgia Bulletin 640.(Revised). 48 pp.A c k n o w l e d g m e n t sThe author is indebted especially to J. FrankMcGill for discussions on this subject since 1959and for sharing his unpublished notes. D. K.Bell, E. W. Hauser, R. H. Littrell, and D. H. Smithmade detailed responses, with examples, to arequest for information and gave permissionfor me to use their views. Appreciation is alsoexpressed to R. W. Gibbons w h o encouragedme to attempt this overview of technologyintegrated w i t h rapid application by growers.M C G I L L , J . F., and S A M P L E S . L. E. 1969. Growingpeanuts in Georgia — A package approach. Pages1-35 in Cooperative Extension Service, Universityof Georgia Bulletin 640.M ILLS, W. T., and SAMPLES, L. E. 1973. Harvesting practices.Chapter 14, pages 4 9 5 - 5 0 8 , in P e a n u t s -culture and uses. American Peanut Research andEducation Association.N O R D E N , A. J. 1980. Crop improvement and geneticresources in groundnuts. Pages 5 1 5 - 5 2 3 in A d -vances in Legume Science. R. J. Summerfield and A.38

H. Bunting, editors. Royal Botanical Gardens, Kew,United K i n g d o m .S M I T H , D. H., and LITTRELL, R. H. 1980. Management ofpeanut foliar diseases with fungicides. Plant Disease64: 3 5 6 - 3 6 1 .39

Session 2 — Research Organizationand DevelopmentDiscussionT. P. YadavaIn Haryana, white g r u b has become an importantinsect pest and a check on groundnutdevelopment and spread. Do we have somemeasures to control this insect?Vikram SinghD. R. C. Bakhetia has been looking for effectivelow cost insecticides, and the use of these asseed dressings.D. R. C. BakhetiaFor w h i t e g r u b control in groundnut, seedtreatment w i t h insecticides has given veryencouraging results. Out of seven insecticidestested, seed treatment with chlorpyriphos 20EC, isofenphos 40 SD and carbofuran 50 WP at2.5 g a.i/kg seed gave an excellent control ofthe pest. The insecticides were also tested incombination w i t h thiram (5 g/kg seed) to checkcollar rot incidence. Thus the control of whitegrub, collar rot and both together helped inobtaining 80 to 144, 104, and 130 to 196%increase in yield over control, respectivelyThese were tried at t w o locations over 2 years.ChairmanThe costs of these seed treatments is l o w relativeto total production c o s tVikram SinghThese treatments are not yet an official recommendation,as they have not been testedby AICORPO.R. W. GibbonsPlease, could P. Gillier give details of seedmultiplication and certification schemes infrancophone West Africa?P. GillierThe schemes are different in each country. InSenegal, there is a government seed service.Seed is g r o w n by farmers under contractFoundation seed is g r o w n by these farmersunder strictly controlled conditions, w i t hspecified seed dressings etc. It is then multipliedby cooperatives and then bought by theseed service for distribution. The seed serviceis a large organization, with good control overthe seed and its purity and germination.In Upper Volta, each farm er receives 10 to 20kg of seed and increases it himself for hissubsequent crops.In Niger, seed is multiplied by farmers undercontract.R. W. GibbonsWhat are the problems of seed multiplicationand distribution in India?Vikram SinghThe initiation of an efficient multiplicationsystem for breeders' seed is one of the shorttermobjectives of AICORPO, so we hope therewill be no further problems. Production offoundation and certified seed is beyond ourreach at present.C. HarknessIn Nigeria, there are difficulties in getting largequantities of new seed. Will the farmers g r o wthe seed for multiplication of the new varieties?Vikram SinghWe plan that the breeder will multiply breeders'seed in the early generations, but aredebating what to do next w i t h regard tofoundation seed. However, certified seed wilthave to be g r o w n on farmers' fields.R. W. GibbonsI have been impressed in the USA by t h enumber of extension workers w h o aregroundnut specialists. Which other countrieshave appointed groundnut specialists to theirextension service?40

K. S. LabanaIn the Punjab, India, we have extension workersw h o are oilseed specialists, based in theUniversities at Ludhiana and Kapurthaia. TheState Agricultural Department has extensionofficers too, not only in groundnut but forother crops also. Most of these people arebreeders.Vikram SinghExtension officers must be specialists in aparticular discipline. We need workers with athorough training especially in entomology,pathology, or agronomy.G. D. PatilWhat are the causes of variation in areas underdifferent groundnut types in Georgia in differentyears?R. O. HammonsThe reasons are not related to soil type norfarmer preference. One is that there areslightly different price structures for differenttypes of groundnut, but the industry is alsoable to interchange end uses between differenttypes, and g r o w those types which givethe grower the m a x i m u m profit. Florunnergives high yield and greatest shelling out-turn,and so favors the grower, w h o is paid onshelling out-turn. We grow for edible use, notfor oil extraction.H. M. IshagIs shelling percentage solely controlled bygenes, or is it controlled also by agronomicpractices? In Sudan, we noted that in badlymanaged crops, we have high shelling percentage(it goes up to 70 to 72%) while in wellmanagedcrops shelling percentage drops to62 to 65%.R. 0. H a m m o n sShelling percentage is an inherent trait, but itdoes vary depending on the time in the growingseason at which pod set occurs, and onotherfactors. In general, Florunner usually has75 to 7 7 % , Florigiant 69 to 7 2 % , and Spanishtypes in between.H. M. IshagWhat is the reproductive efficiency of Florunner?R. 0. HammonsWe do not know what the reproductive potentialof these varieties is.U. R. MurtyDoes the overproduction of flowers ing r o u n d n u t r e p r e s e n t a n e v o l u t i o n a r ymechanism related to survival or does it alsorepresent a potential for increasing the productivity?R. 0. HammonsWe have recovered 1400 seeds, plus 700 pegswhich had not matured at harvest, f r o m asingle plant. In the same trials we had morethan 1000 seeds on over 20 plants. Can wetransplant cuttings, say of F 1 hybrids, andachieve improved yields?H. T. StalkerCuttings of Fi hybrids will not produce asmany seeds as plants g r o w n f r o m seedlings.The reproductive efficiency of most cuttings ismuch lower than seedlings; much of this isdue to fewer branches being produced onmost cuttings. Also the cotyledonary lateralbranches usually produce most of the plant'sseeds, but cuttings do not have these highlyproductive branch structures. The conclusionis that a field of F 1 cuttings probably will notproduce as much per hectare as seedlings of agood variety.J. S. ChohanWith the use of Benlate, was there an increasein the incidence of rust in the course of time? Ifso, h o w did you face this problem?R. O. HammonsRust is not a problem in USA except in Texas.D. H. SmithBenlate is not effective against rust. Rust issometimes more severe w h e n Cercosporaleaf spots are controlled by Benlate, becausethe competition with the leaf spots is eliminated.Vikram SinghThe yield levels of 3500 kg/ha in Georgia areimpressive; much of this is due to growingFlorunner. Has the full yield potential ofFlorunner been exploited, or is there still a gap41

etween existing yields and potential yield?R. O. HammonsSome groundnuts are g r o w n on poor land notideally suited to them. Some of the yieldsobtained by the better farmers on g o o d land(up to 7300 kg/ha) compare well with the bestyields on our experimental plots (which arenot on the best land!).S. H. PatilAccording to Dr. Vikram Singh of ICAR in India,about 8 years are required for a variety ofgroundnut before recommending it for generalcultivation. H o w many years of evaluationare required in the USA for similar recommendation?R. 0. HammonsNormally 3 years of trials are needed beforethe state can recommend a new variety, but ifalready recommended in another state, only 2years are necessary. We also test our breedinglines, so we have 3 to 5 years of test data. T w oorganizations are involved in release and productionof seed. The Georgia Foundation SeedDevelopment Corporation takes the seed f r o mpublic breeders and multiplies it on stateownedfarms in the foundation generation;that seed is then sold to farmers in the GeorgiaCrop Improvement Association w h o multiplythe seed under supervision, and the Agencycertifies the seed.S. M. MisariI was impressed w i t h the ever-increasingyields in groundnuts in the USA. In Nigeria atthe m o m e n t we have one extension worker to2000 to 3000 farmers. May I know h o w youhave gone a b o u t y o u r extension methodologyand w h a t is the present ratio of extensionworkers to farmers in the USA?R. O. H a m m o n sThe basis of the service is the six-man extensionteam, and a County Agricultural Agent ineach county. There are about 75 extensionofficers for 16 000 farmers, or about 1 to every200 farmers.K. S. LabanaIs there any micronutrient problem in USA? InPunjab we are facing micronutrient problemslike deficiency of Zn, Fe, M n , and Ca ingroundnut soils.R. O. H a m m o n sI can't provide details now, but write to me andI will send y o u the information.J. A. ThompsonWhat is the place of inoculation with rootnodule bacteria in the package deal for growinggroundnut in USA?R. O. H a m m o n sWe use a complete fertilizer, 400 lb/acre of5:10:15 or 4:12:12. Groundnuts usually followprevious groundnut crops, so less than 0 . 1 %of farmers use inoculum; usually this is onland cropped to groundnut for the first time.B. S. GillDr. Hammons, you indicated that the areaunder Florunner increased rapidly in the 70s,and during the same period the area of irrigatedcrop also increased. I would like to knowthe relative contribution of the improved varietyand the irrigation.R. O. HammonsThere is a 10 to 16% yield increase withirrigation; there are variety responses to irrigationand to excess irrigation; some varietiesgive a 2 0 % yield increase when irrigated.N. D. DesaiDo you have areas under rainfed conditions(without irrigation)? Is there any productiontechnology developed for such areas or is anyvariety available?R. O. HammonsI am sorry, we cannot offer you technology orreleased varieties. We have noted in varietytrials that one of our lines, T i f t o n 8', growsbetter and wilts later than other varietiesunder drought conditions, and we will makeseed available if you request it. It does notrespond well under ample moisture, however.P. S. ReddyN o w that more than 50% of groundnut inGeorgia is irrigated I presume that a lot ofinformation might have been accumulated onirrigation studies. Can Dr. Hammons kindly42

enlighten us on the following?a. The critical stages of moisture stress fordifferent habit groups?b. Quantum of irrigation water required perirrigation?R. 0. HammonsThere is not an easy answer, as we get "irrigati o n " f r o m frequent showers in addition to theirrigation water applied. The results f r o m rainoutshelter studies are available and can bereferred to for details.M. A. AliDr. Hammons mentioned that deep plowinghas helped to control Sclerotium rolfsii. Wasthe control permanent or did the fungus becomemore serious when that particular pieceof land was deep plowed again after 1 or 2years?M. K. BeuteDeep plowing is a short-term control measure.Its effectiveness depends on when the debrisis brought back to the surface.D. J. NevillHow will Title XII interact with ICRISAT Projects,and how will ICRISAT feature in theplanning stage?C. R. JacksonICRISAT will be written into projects whereapplicable. Also Title XII will not duplicateon-going, well-funded projects.J. S. SainiThere is a strong observation that groundnutsown for the first time in a field gives goodyield under Punjab conditions. But the samefield after 3 to 4 years of continuous groundnutcultivation shows a considerable decline inyield, even with the adoption of the sameproduction technology. Have you observedthis phenomenon in USA also, and w h a t canbe the possible reasons for this decline undersuch a situation?R. O. HammonsOur package includes intensive crop protection,so we do not have such problems.ChairmanAny comments on monocropping?N. D. DesaiIn Gujarat, groundnut is grown year after yearand f r o m generation to generation in the samefield. Not only that, but in the same furrow —yet, there are no observations about declinein yield.S. V. JaiswalGroundnut, when cultivated for the first timein the Punjab in a sandy field, will yield as highas 3 tonnes/ha. The farmers felt very muchencouraged and during the second year, withthe application of the same inputs, the yieldcame d o w n to 1 Vi to 2 tonnes/ha. This suddendecline in yield during the second year ofgroundnut cultivation needs to be explained.This occurs especially in sandy soils.J. S. ChohanThe explanation for the difference betweenthe sandy soils of the Punjab and the heaviersoils elsewhere is probably that in the sandysoils there are fewer microorganisms whichare antagonistic to the survival of the pathogenin the soil between crops, so the secondand subsequent crops are exposed to higherlevels of inoculum than a crop in a field sownto groundnuts for the first time.43

Session 3Genetics and BreedingChairman: R. O. Hammons Rapporteurs: S. L. DwivediR. W. GibbonsD. McDonaldS. N. Nigam

Groundnut Genetic Resources at ICRISATV. R. Rao*It is well known that the success of modern cropcultivars, the population explosion and thedisturbance of the ecosystem have togethertended to reduce the genetic variability in plantresources available to man. The grower, processor,distributor and consumer have demandeduniformity in crop varieties and foodproducts. The plant breeder, to meet thesedemands, has reduced the genetic diversity inour major crop species and this has oftenresulted in their increased genetic vulnerability.In a way, plant breeders have become victims oftheir own success. With diversity existing inlandraces being replaced by homogeneous improvedcultivars, the danger of genetic erosionhas become serious (USDA 1979). Ingroundnut, this process started as far back as1875 when Holle introduced into Java the Waspadacultivar, maturing in 4 - 5 months, thatcompletely replaced native cultivars maturingin 8 - 9 months (Hammons 1973).With modernization and urbanization, thenatural environs of wild and weedy specieshave been disturbed and some may becomeextinct. Natural habitat destruction, which occursonly slowly, can be seen happening todayin South America as far as Arachis species areconcerned. It is imperative that whatever geneticdiversity remains should be assembled andconserved. This may be for immediate utilizationin crop improvement, or for future utilizationwhen the situation is expected to be evenmore alarming.Arachis Genetic ResourcesGroundnut ranks 13th in importance among theworld food crops and is the most importantfood legume (Vamell and McCloud 1975). Comparedto other oilseed crops and grain legumes,it is relatively daylength insensitive and has a* G r o u n d n u t G e r m p l a s m B o t a n i s t , G e n e t i csources Unit, ICRISAT.Rehighoil and protein content. As a crop it is welladapted and is readily accepted as a food.Groundnut is grown on about 20 million hectares,extending f r o m tropical to temperatezones, in about 80 countries. The major productionzones are in the semi-arid tropics. Averageyields in the developed world are about 2000kg/ha, but the world average is less than 900kg/ha.Arachis genetic resources include all the wildspecies and the cultivars under production. Thegenetic diversity in cultivated groundnut hasbeen continuously eroded in the groundnutgrowingcountries since crop improvementwork started in this crop. This process is veryclear in India and in some African countries,where improved cultivars have been introduced,and the older landraces have almostcompletely disappeared. In some regions ofmany groundnut-growing countries, the processis slow and timely collection now wouldresult in conservation of such landraces. InSouth America, where Arachis originated,much valuable material exists. The developmentalactivities in many of the countries in thisregion w o u l d soon result in the loss of thisvaluable germplasm (W. C. Gregory, personalcommunication). Hence there is an urgent needto collect and conserve Arachis germplasmfrom these countries.Some efforts to collect and conservegermplasm have been done in a few placesaround the world in a fragmented manner.Some of the major known Arachis collectionsare listed in Table 1. There is, undoubtedly, acertain amount of duplication in these collections.Table 2 lists the catalogs known fromvarious centers of conservation. From the list,one may take the vastness of the resources forgranted. Gregory et al. (1973) have warnedabout such a possible misconception. Thesereserves are finite and exhaustible. Harlan(1976) has indicated the limitations of our potentialgenetic resources in the light of thepossible genetic wipe out of the center of47

T a b l e 1 . K n o w n sources o f g r o u n d n u t g e r m -p l a s m collections.T a b l e 1. ContinuedCountryInstitute / OrganizationCountryUSAInstitute/organizationa. Southern Regional Plant IntroductionStation (SRPIS), Experiment,Georgiab. N o r t h Carolina State University,Raleighc. University of Georgia, Tiftond. University of Florida, Gainesvillee. Texas A & M University, Stephenvillef. Oklahoma State University, Stillwaterg. Tidewater Research Center, SuffolkAustraliaMalaysiaDepartment of Primary Industries,Kingaroy, QueenslandMalaysian Agricultural Researchand Development InstituteIndia a. Oilseeds Research Directorate,Hyderabadb. All India Coordinated ResearchProject on Oilseeds (AICORPO)ArgentinaBrazilVenezuelaSenegal,Upper VoltaIvory Coast,Niger etc.Nigeriaa. University of the North-East, Corrientesb. National Institute for Agricultureand Technology (INTA), Cordobaa. A g r o n o m y Institute, Campinasb. CENARGEN/EMBRAPA, BrasiliaCENIAP, Maracaya. Oils and Oilseed Research Institute(IRHO), Paris, Franceb. Senegalese Institute of AgriculturalResearch (ISRA), Bambey,SenegalInstitute of Agricultural Research,A h m a d u Bello University (Samaruand Kano)Malawi M i n i s t r y o f A g r i c u l t u r e a n dNatural Resources (Chitedze ResearchStation)S. Africa Department of Agricultural TechnicalServices, Potchefstroom.Z i m b a b w eSudanIsraelCrop Breeding Institute, SalisburyGezira Research Station, W a d Medania. Ministry of Agriculture, The VolcaniCenter, Bet-Dagonb . T h e H e b r e w U n i v e r s i t y o fJerusalem, RehovotT a b l e 2 .G r o u n d n u t c a t a l o g s a v a i l a b l e a tI C R I S A T .Index S e m i n u m Varietiesd'arachide (Arachishypogaea)List of GroundnutG e r m p l a s m ,PotchefstroomCatalog of Seed Available atthe SRPIS, Georgia, USACultivated GermplasmCatalog-PeanutsGermplasm Screened atDelhi, Ontario, CanadaGroundnut Germplasm Bankin IndiaCatalogo Analitico dePoblaciones de M a n iGroundnut Seed Stored atNSSLPartial List of GroundnutAvailable at CBI, Z i m b a b w ePeanut AccessionsISRA, CNRA,Bambey, SenegalDATS, Republicof S. AfricaA R S - U S D A , USA(1974 & 76)NCSU, Raleigh,USAUniversity ofGuelph, Guelph,CanadaAICORPO (ICAR),IndiaINTA, ArgentinaNSSL, Fort Collins,USACBI, Salisbury,Z i m b a b w eNPGRL, Laguna,PhilippinesJapanChinaKochi University, Kochi-kenNational A c a d e m y of AgriculturalSciences, BeijingList of Introductionsf r o m 01/61 to 08/76The HebrewUniversity ofJerusalem,Rehovot, IsraelIndonesiaCentral Research Institute for Agriculture,BogorContinuedList of Arachis G e r m p l a s mEMBRAPA-CENARGEN, Brazil

diversity and Hawkes (1979) clearly describedthe ways in which such a w i p e out may occur. Itis clear to everyone concerned that there is anurgent need to collect and conserve Arachisgenetic resources if we are, indeed, to cope withthe present and future groundnut improvementproblems. Realizing this urgency, ICRISAT hasbeen designated by the Consultative Group onInternational Agricultural Research (CGIAR) asa major repository for Arachis germplasm andhas been charged with the responsibilities ofgenetic resources activities.Arachis G e n e t i c R e s o u r c e sa t I C R I S A TThe work in the groundnut improvement programwas initiated at ICRISAT in 1976. Simultaneouslythe genetic resource activities alsocommenced. The objectives are collection,maintenance and evaluation of Arachis geneticresources and documentation and distributionof seed material and information. During 1979,the genetic resources work was reorganizedwith the creation of the new Genetic ResourcesUnit which took over the germplasm work in allfive ICRISAT mandate crops. This did notchange the basic scope and objectives ofgroundnut germplasm work. Figure 1 showsthe basic activities of the Genetic ResourcesUnit.C o l l e c t i o n a n d A s s e m b l yPresent StatusInitially the major available resources wereidentified. Top priority was given to acquiringcollections available at various known centersfor ICRISAT. All the available collections fromvarious research institutes in India were donatedto ICRISAT and about 5000 accessionshave been obtained in this manner (Table'3).This material, which has been obtained with theexcellent cooperation of many institutions andin particular with the Indian Council of AgriculturalResearch (ICAR), consists of many intro-COLLECTIONSFROM INDIADISCARDDUPLICATESREJUVENATIONREGISTRATIONSYSTEMATICEVALUATIONCLASSIFICATIONAND SEED INCREASECOLDLONGTERMSTORAGEUTILIZATIONFOREIGN COLLECTIONSANDINTRODUCTIONSDOCUMENTATIONDISTRIBUTIONFigure 1. Genetic Resources Unit, ICRISAT — Operational flow chart.49

ductions, reselections f r o m such introductions,and experimental types developed within India.Similarly about 3000 accessions have beenobtained f r o m the USA, Japan, United Kingdo m , Senegal, Malawi, USSR, Nigeria, Zimbabwe,South Africa and China (Table 4).ICRISAT has initiated a contractual arrangementw i t h North Carolina State University, Raleigh,USA for the supply of groundnut germplasmheld at that center.In addition, ICRISAT has undertaken severalcollection expeditions w i t h i n India and abroad,and a total of 598 accessions have been obtainedso far (Tables 5 and 6). Generally randomsampling technique is used for collection ofseed from farmers' fields and seed is collectedf r o m as many plants as possible. During collecti o n trips, a p a r t f r o m collection of seed material,information on cultivation practices, location,pests and diseases is also collected. For thispurpose, a germplasm collection data sheet hasbeen developed.T a b l e 3 .T r a n s f e r s f r o m I n d i a n centers.T a b l e 4 . Tansfers f r o m c e n t e r s a b r o a d .Institute/locationAccessionsCountryAccessionsAndhra Pradesh AgriculturalUniversity, Kadiri & Karimnagar 1364Rajendra Agricultural University,Ranchi 103Mahatma Phule Krishi Vidyapeeth,Jalgaon 263G.B. Pant University ofAgriculture and Technology,Pantnagar 11Agricultural Research Station,Durgapura 58USA 2066Japan 74United Kingdom 20Malawi 263Senegal 16USSR 3Z i m b a b w e 151South Africa 33Nigeria 103China 5Total 2724All India Coordinated ResearchProject on Oilseeds, Tindivanamand Pollachi 681Gujarat Agricultural University,Junagadh 1154T a b l e 5.C o l l e c t i o n of local c u l t i v a r s — India.Oilseeds Experiment Station,Tindivanam 368Punjab Agricultural University,Ludhiana 495National Bureau of PlantGenetic Resources, Amravati 159Bhaba A t o m i c Research Center,Bombay 9Punjabrao Krishi Vidyapeeth, Akola 112Regional Wheat Rust ResearchStation, Mahabaleswar 5Tamil Nadu AgriculturalUniversity, Coimbatore 29Others 67Total 4969M o n t h Year State AccessionsMar/Apr 1976 Bihar, Orissa, andTamil Nadu 11Nov/Dec 1976 Tamil Nadu, andAndhra Pradesh 23Sept/Nov 1977 Rajasthan 7Sept/Oct 1977 Karnataka (south) 35Oct/Nov 1977 Andhra Pradesh 92Apr 1978 Andhra Pradesh 4Oct 1978 Maharashtra 1Oct 1978 Karnataka (north) 151A p r 1979 A n d h r a Pradesh 6Apr/May 1979 Karnataka (south)and A n d h r a Pradesh 101May 1979 Maharashtra 1Aug/Sept 1979 Maharashtraand Gujarat 19Oct 1979 Uttar Pradesh 150

Table 6. Collection of local cultlvars -abroad.Month Year Country AccessionsMar/AprAprAprAug/SeptJune19791979197919791980BoliviaNepalMalawiSomaliaZambia121333583Table 7.Yearly acquisitions.Year Accessions Total1976 2443 24431977 3565 60081978 925 69331979 1216 81491980 349 8498(August)Up to mid-1980, about 8500 accessions hadbeen assembled and Table 7 gives the yearlyacquisition of this material. Table 8 presents theavailable germplasm, by country. Apart f r o mthis, 1536 accessions f r o m various countries arecurrently under quarantine inspection (Table 9).ICRISAT has a special interest in the wildspecies of Arachis for cytogenetic and resistancebreeding work. Some species (Table 10)have already been obtained from the TamilNadu Agricultural University, Coimbatore, India;North Carolina State University, USA; andReading University, U.K. and have been establishedat ICRISAT. The collection from ReadingUniversity consists of material originally f r o mNorth Carolina State University, Raleigh;Oklahoma State University, Stillwater; TexasA & M University, Stephenville; ARS-USDA,Tifton, Georgia, and the Division of Food Crops,Campinas, Brazil. More material is still beingtransferred. At the moment the wild speciesmaterial is maintained jointly by the GeneticResources Unit and Groundnut CytogeneticProgram.Future PrioritiesThe IBPGR/ICRISAT ad hoc Committee onGroundnut Germplasm (September 1979) hasassigned the following priorities for immediatecollection:RegionSouth AsiaSoutheast AsiaMeso AmericaWest AfricaEast AfricaCountriesBurmaIndonesiaMexico, Central America,and Caribbean IslandsSenegal, Nigeria,Upper Volta,and GambiaMozambiqueSouth AmericaBrazil, Argentina, Peru,Bolivia, and ParaguayGregory et al. (1973) have described thedistribution of the genus Arachis in SouthAmerica, where more intensive collecting isnecessary to obtain valuable germplasm. Effortsare being made to launch expeditions incollaboration with the IBPGR and CENARGEN/EMBRAPA (Brazil).QuarantineThe importation of exotic groundnut material issubject to strict quarantine regulations laidd o w n by the Government of India in order toprevent the entry of new pests or diseases intothe country. ICRISAT obtains the seed in theform of shelled seed accompanied by regularphytosanitary certificates. The seed is plantedin plastic pots in the screen house at the CentralPlant Protection Training Institute (CPPTI),Rajendranagar. CPPTI has been authorized bythe Ministry of Agriculture, Government ofIndia, to conduct quarantine work for ICRISATmandate crops. The seedlings remain underclose examination for 6 weeks. Then thematerial is transferred, and transplanted, in thePost Entry Quarantine Isolation Area (PEQIA)which is located in an isolated corner of theICRISAT farm. The seedlings are inspectedevery week by a joint CPPTI-ICRISAT team andany plants showing suspicious symptoms areuprooted and destroyed. At maturity, the seedis harvested f r o m the healthy plants and isreleased. These procedures allow an excellentworking relationship between the Genetic ResourcesUnit and the quarantine authorities.For export, seeds f r o m healthy plants arecollected. The seed is examined by the Indianquarantine authorities and is then despatched51

T a b l e 8 . G r o u n d n u t g e r m p l a s m — s o u r c e c o u n t r i e s ( A u g u s t 1 9 8 0 ) .Country Accessions Country AccessionsAFRICA Brazil 243Angola 2 Chile 12Dahomey 6 Ecuador 2Egypt5Gambia5Ghana 6Paraguay 101Peru 62Uruguay 20Guinea 2 Venezuela 8Ivory Coast 24 Others 114Kenya 28Liberia 10 813Libya 1MadagascarM a l a w iMaliMauritiusMoroccoMozambiqueNigeriaSenegalSierra LeoneSouth AfricaSudan8659751016785742674ASIABurmaChinaCyprusIndiaIndonesiaIranIsraelJapanMalaysiaTanzania 110 Philippines 6UgandaUpper VoltaZaireZambiaZ i m b a b w eOthersN.C. AMERICACubaCosta RicaHonduras5710111037784Sri LankaTaiwanTurkey16162517152563144131720320631827EUROPEBulgariaGreece24Holland 5Spain 1111 123Jamaica1Mexico 6 OCEANIAPuerto Rico 19 Australia 45USA 1240 Fiji 11281 46SOUTH AMERICA USSR 49Argentina 195Bolivia 56 U n k n o w n 199152

T a b l e 9 . Accessions u n d e r q u a r a n t i n e .CountryAccessionsBurma 5China 10Indonesia 60Italy 27Malawi 6Malaysia 56Nepal 1Senegal 341South Africa 133USA 814Zambia 83Total 1536T a b l e 1 0 . Arachls spp at I C R I S A T .tries, and genetic drift (Allard 1970). Goodstorage conditions coupled w i t h proper growoutsare expected to reduce the effects of suchproblems.At ICRISAT all the cultivated groundnut accessionsand seed producing wild species aremaintained by growing o u t In the case of thecultivated groundnut, only pods attached to theplants are harvested. In the case of seed producingwild species material, which are considerablyspace planted, all the pods are collected. Therhizomatous and nonseed producing wildspecies are maintained in either brick chambersor concrete rings to prevent contamination.Rejuvenation is carried out by rooting stemcuttings and rhizomes. As the long-term coldstorage facilities are still under construction,about one-third of the collection is plantedevery year for multiplication and rejuvenationduring the postrainy season when there is lessincidence of pests and diseases.A. duranensis A. glabrataA. batizocoi A. repensA. correntina A. sp (10038 LL & SL)A. chacoense A. sp (C 565-66)A. cardenasii A. sp (C 9990, 9993,10002)A. villosa A. sp (Man. 5)A. stenosperma A. sp (Man. 8)A. monticola A. sp (30008)A. pusilla A. sp (30098)A. paraguariensis A. sp (30093)A. villosulicarpa A. sp (30011)A. rigonii M a n y accessions ofA. hagenbeckii Rhizomatosaeto the consignee with phytosanitary certificateissued by the Government of India. This work iscarried out at thequarantine laboratory situatedin the ICRISAT Center under the supervision ofCPPTI personnel.MaintenanceThe procedures followed in conservation,maintenance, and storage present many problems.In maintaining the genetic purity of theconserved accessions, problems may arise dueto differential survival in storage, selection duringrejuvenation, out-crossing w i t h other en-Types of CollectionThough there is no recommendation regardingthe types of groundnut collections to be maintainedat ICRISAT, it is envisaged that thefollowing types w o u l d be maintained:A C C E S S I O N S COLLECTION. This includes all theavailable groundnut accessions at ICRISAT. Itwill be maintained in long-term cold storage.W O R K I N G C O L L E C T I O N . ( B A S I C C O L L E C T I O N )This includes lines chosen and stratifiedby botanical variety, geographical distributi o n and ecological adaptation. This w o u l drepresent the genetic diversity available in thegroundnut germplasm.W I L D SPECIES COLLECTION. This includes all thewild species of Arachis which have to be maintainedseparately due to problems of handling.N A M E D CULTIVAR COLLECTION. All the cultivarsnamed and released by public and privateinstitutions will be included in this collection.G E N E T I C S T O C K COLLECTION. This collectionincludes all the sources of resistance to pestsand diseases, lines with specific desirable traitsand stocks with known genes.53

StorageAt present the collection is stored as unshelledpods in airtight containers in temporary storeswhich are not airconditioned. The m e d i u m -term cold storage facility w h i c h has been recentlycompleted, with 4°C temperature and35% relative humidity, is n o w available forstoring g r o u n d n u t g e r m plasm. The long-termfacility (- 18°C) has been approved for constructionand should be completed by the end of1981.E v a l u a t i o n a n d U t i l i z a t i o nCollection, maintenance, and conservation havesignificance in elucidating taxonomic statusand evolutionary relationships between andw i t h i n the species. But the main justification forgenetic resource conservation is for utilizationin crop improvement. The key to successfulutilization of variability f r o m broad geneticpools requires the knowledge of desirable traitsavailable in the germplasm. This requires asystematic evaluation of the germplasm. AtICRISAT, a multidisciplinary approach is followedand the available groundnut collection isevaluated by all the groundnut scientists.The preliminary evaluation is carried out inthe PEQIA and during the first g r o w out formultiplication. The material is evaluated forabout 32 morphological and agronomic characters.Promising material is then evaluated byother disciplines. Table 11 gives some of thesources selected for resistance to pests anddiseases. These lines are being extensivelyused in the breeding program to incorporateand improve the existing cultivars. Lines identifiedelsewhere as early maturing and highyielding, and which are in the ICRISAT collectionare also being used in the respectivebreeding programs.In the near future, germplasm will also beevaluated for other useful attributes such asdrought tolerance, high oil content and sourcesof resistance to other pests and diseases. It isalso intended that in future, multilocation testingof s o m e of the germplasm lines will becarried out. At present, part of the ICRISATgroundnut germplasm is being evaluated inVertisols in Junagadh, Gujarat, in collaborationwith National Research Center for Groundnut.T a b l e 1 1 . P r o m i s i n g g r o u n d n u t g e r m p l a s m l i n e s .Promising linesCharacterLeaf Spot(Cercosporidiumpersonatum)Cultivated(ICG Nos)2716, 7013, 4747,6340, 6022W i l d speciesPI 338280 (A. sp HLK-410),PI 338448 (A. pusilla),PI 276233 (A. sp 10596),PI 276235 (A. chacoense)A. chacoense x A. cardenasii,A. glabrataRust1697, 7013, 2716,4747, 6340, 6022,1703, 1705, 1704,1707, 1710, 6280,4746PI 219823 (A. duranensis),PI 331194 (A. correntina),PI 262141 (A. cardenasii),PI 276235 (A. chacoense)A. chacoense x A. cardenasiiPl 338448 (A. pusilla),PI 262848 (A. sp 9667),PI 276233 (A. sp 10596),A. villosa, A. villosulicarpa,Continued54

T a b l e 1 1 . ContinuedCharacterCultivated(ICG Nos)Promising linesWild speciesA. glabrataPI 298639 (A. batizocoi),PI 338280 (A. sp HLK-410)Leaf Spot andRust2716, 7013, 4747,6340PI 338280 (A. sp HLK-410),PI 338448 (A. pusilla),PI 276233 (A. sp 10596),PI 276235 (A. chacoense),A. chacoense x A. cardenasiiA. glabrataAflaroot rot 1326 Not testedCollar rot 3263, 1326 Not testedAspergillusflavus1326, 4749, 4750 Not testedPod rot 3 3 3 6 , 3 3 3 4 , 2 9 5 1 ,1326, 1711,2031Not testedTomato SpottedWilt Virus1656,799 PI 262848 (A. sp 9667),PI 338448 A. pusilla),A. glabrata, PI 276233(A. sp 10596)Peanut MottleVirus2716, 4747 (Viruspresent in the plantsbut does not go to theseed)Not testedC l u m p Virus 7677,5123,5118,8030, 3894, 6313,5210, 949Not testedThrips andJassids5042, 5044, 50415043, 5045, 5040,2271PI 276235 (A chacoense),PI 298639 (A batizocoi)AphidsSingle plant selectionsf r o m 5040PI 276235 (A. chacoense),PI 298639 (A. batizocoi)Termites 5045, 5929, 5040,5143, 2316, 1326Not testedLeaf miner 1697, 1703, 1704,5075, 2283, 2349Not testedNodulation andBNF capacity1561,2405,404 Not tested55

Apart f r o m this, the germplasm lines areevaluated systematically for yield and otherattributes. Substantial a m o u n t s of suchgermplasm are being utilized in various breedingprojects which w o u l d help to broaden thegenetic base of the material that goes out ofICRISAT. S o m e of t h e earlier selections madef r o m s o m e accessions such as Robut 33-1, havebeen supplied to the breeders and promisinglines have been selected f r o m this material.DocumentationProgress in the field of plant genetic resourcesis related to the conservation of eroding geneticresources and utilization of this material forcrop improvement work. Success partly dependson the availability of information on thematerial being conserved. W i t h t h e f o r m a t i o n ofinternational institutes, information exchangehas assumed global importance, necessitatinga certain amount of uniformity in data collection,recording, storage, and retrieval. The InternationalBoard for Plant Genetic Resources(IBPGR) is expected to play a key role in bringingan understanding among the workers in manycountries on these aspects and in the internationalexchange of information.A c o m m o n descriptive language is imperative.Attempts to develop such a descriptivelanguage for groundnut (genus Arachis) is underway, in close collaboration with IBPGR. TheIBPGR/ICRISAT ad hoc C o m m i t t e e onGroundnut Germplasm which met during September1979 appointed a subcommittee tofinalize the descriptors for groundnut. The subcommitteemet during July 1980 and hasevaluated a list of critically prepared descriptorsand a final draft for the approval of the membersis under preparation. This list contains 32 descriptorsfor passport information and 40 descriptorsof a morpho/agronomic nature. Descriptorson disease and pest reaction are to beadded to this list. After approval the descriptorswill be circulated a m o n g groundnut workersand then a finalized list will be published. A listof the descriptors used for g r o u n d n u tgermplasm at ICRISAT is s h o w n in Table 12.Since the descriptive language is under preparation,t h e data recorded during the last f e wevaluations in ICRISAT site have not beenstored on the computer. However, these evalua-Table 12. List of the descriptors used forgroundnut germplasm at ICRISAT.Passport Data:1. ICG number2. S y n o n y m n u m b e r - 13. S y n o n y m n u m b e r - 24. S y n o n y m number - 35. S y n o n y m n u m b e r - 46. Sample type7. Collector's name and number8. Collection date9. Sample source10. Donor11. Pedigree12. Species, subspecies and variety13. Cultivar14. Pedigree15. Origin16. Province/state and nearest village17. Altitude, latitude, and longitude18. Local name19. Soil type20. RemarksMorphological Data:1. Branching pattern2. G r o w t h habit3. Stem color4. Stem hairiness5. Peg color6. Standard petal color7. Standard crescent8. Standard size9. Leaf color10. Leaf shape11. Leaf size12. Pod type13. Pod beak14. Pod constriction15. Pod reticulation16. Pod length17. Pod size18. Number of seed/pod19. Seed color20. Seed size2 1 . Seed shapeAgronomic Evaluation Data:1. Date of planting2. Days to emergence3. Seedling v i g o r4. Days to 5 0 % flowering5. Plant height (cm)Continued56

T a b l e 1 2 . Continued6. Plant w i d t h (cm)7. Total mature pods/plant8. 100 seed weight (g)9. Yield (g/plot)10. Date of harvest11. Days to maturityThe seed despatch to the scientists in India andabroad is one of the important activities undertakenby the Genetic Resource U n i t Table 13gives the details of seed distributed so far.ReferencesA L L A R D , R. W. 1970. Population structure and samplingmethods. In Genetic resources in plants — theirexploration and conservation.T a b l e 1 3 . D i s t r i b u t i o n o f g r o u n d n u t g e r m -p l a s m .Scientists in IndiaScientists abroadScientists in ICRISAT538332624914GREGORY, W. C. GREGORY, M. P., KRAPOVICKAS, A.,S M I T H , B. W., and Y A R B R O U G H , J . A., 1973. Structureand genetic resources of peanut. Pages 17-46 inPeanuts — culture and uses. American Peanut Researchand Education Association.H A R L A N , J. R. 1976. Genetic resources in wild relativesof crops. Crop Science 16: 3 2 9 - 3 3 2 .tions, which used many of the proposed descriptors,can be computerized as soon as the descriptorsand descriptor states are finalized. Thecomputer file f o r m s the base for a live catalogand only special lists will be published.DistributionH A W K E S , J. G. 1979. Germplasm collection, preservationand use. Presented at the Plant BreedingSymposium-ll. 1 2 - 1 6 March 1979, Iowa State University,A m e s , Iowa, USA.USDA (U. S. D E P A R T M E N T OFAGRICULTURE). 1979. Plantgenetic resources — conservation and use. Preparedby the National Plant Genetic ResourcesBoard. U. S. Government Printing Office.VARNELL, R. J., A N D M C C L O U D , D. E. 1975. Pages 1-19in Germplasm preservation and genotype evaluationin Arachis. International Peanut Program,Gainesville, Florida, USA.57

Breeding Methodology for GroundnutsA. J. Norden*The development of improved cultivars is themajor responsibility of the plant breeder. Toaccomplish this the breeder must have first, aknowledge of the botany, genetics, and ecologicalrequirements of the crop; second, establishsound breeding objectives; t h i r d , collect orcreate a range of genetic variability; and fourth,develop or devise the most suitable breedingmethod to fulfill the objectives. It is in theperformance of this last fundamental thatbreeders reach their best potential and accomplishtheir most important role.Before proceeding into a discussion ofgroundnut breeding methodology, however, Iwant to first emphasize the importance of thefirst three fundamentals to the groundnut improvementprocess. The modern breeder isdependent to a large degree on the contributionsand cooperation of researchers in manyother disciplines. T h e heart of a breeding programis the evaluation or screening of breedingmaterial, whether it is to find the most suitableparents to use in a cross for a particular objective,or to isolate the superior progeny resultingf r o m a cross. Groundnut breeders are dependenton pathologists, entomologists, chemists,engineers, physiologists, nutritionists, etc., notonly for providing basic knowledge on thesubject, but also for assistance w i t h the developmentof suitable screening techniques.Only limited information is available regardingthe breeding behavior of groundnuts, thenature of inheritance, and the physiologicalimplications of important characteristics. Ingroundnuts, where the end product is utilizedprimarily for human consumption, additionaldata are required for reasonable certainty that* A g r o n o m y Department, University of Florida,Gainesville, Florida 32611, USA.Note: This paper w a s prepared to supplement info r m a t i o n presented in slides at the Internati o n a l W o r k s h o p o n G r o u n d n u t s , O c t o b e r1 3 - 1 7 , 1980 at ICRISAT, Hyderabad, India.the new cultivar will excel, not only in yield, butalso in processing and end-use product quality.Determining the inherent processing, flavor,and keeping quality of groundnut lines is one ofthe more difficult tasks facing breeders. Someof the older chemical tests are not completelyapplicable today, such as iodine value and fattyacid composition. Taste and flavor are affectedby the environment and handling of the crop, aswell as by the genotype. Processors and consumershave little interest in yield. Thus, s o m eof the highest yielding lines are not being g r o w ncommercially today.Breeding ObjectivesThe procedures involved in the development ofnew groundnut cultivars optimistically spana period of 10 to 20 years. In view of thisand the changing trends in utilization and productionmethods, establishing sound objectivesis extremely important in a breeding program.The broad objective is to develop cultivarsthat are currently in demand by the producer,the processor, and the consumer. It is importantto eliminate the defects which hamper a cultivar'susefulness in a given region or period oftime. It is only within the past couple of yearsthat the energy requirements and/or contributionsof groundnut cultivars in the f o r m ofnitrogen fixation have become objectives ofimprovement programs.Branch (1979) with the aid of several U.S.groundnut breeders recently compiled a list ofgroundnut breeding goals. For the grower theyinclude higher yields, more pest resistance, andm o r e environmental stress-tolerance. Tosatisfy the processor, groundnut breeders areattempting to produce cultivars with more unifo r m maturity and more favorable mechanizationand processing characteristics. The concernof the plant breeder for the consumerinvolves trying to incorporate nutritional seedproperties into cultivars w i t h fruit and seed of58

preferred shape, size, texture, color, flavor, andaroma.Genetic VariabilityIt is a prerequisite to cultivar improvement. Theprevious paper by Dr. V. R. Rao concernedgroundnut germplasm resources. Fortunately,there is a considerable amount of variabilityavailable in the cultivated species, especially inmorphological and chemical characteristics.The oil content of different genotypes variesf r o m less than 4 0 % to over 60% and the fattyacid composition of the oil of different linesalso shows considerable variability. Somegroundnut lines have polyunsaturated to saturatedoil ratios of almost 2 : 1 , the ratio considereddesirable for reduction of blood serumcholesterol. Genetic variability is also availablewithin the species to increase some deficientamino acids, especially methionine, but morevariation is needed.M o r e resistance to certain diseases,nematodes, toxin-producing molds, and todrought is also required. Progress in cultivardevelopment will be enhanced as we improveour ability to identify and incorporate the desiredcharacteristics into improved cultivars. Abetter understanding of the cytogenetics ofArachis species is needed in order to deviseprocedures that will enable the transfer ofdesirable traits from the w i l d species to becultivated. This area is the subject of the nextSession on the program of this Workshop.Groundnut BreedingMethodologyAn in-depth review of the literature ongroundnut breeding prior to 1972 was publishedin Peanuts — Culture and Uses (Norden1973) and a later review covering the period1972 to 1977 in Advances in Legume Science(Norden 1980). As I had emphasized in the latterpaper, " n e w and spectacular discoveries inplant breeding methodology, not only ingroundnuts butalso in other crops, are rare, andthat there had not been any major advances ingroundnut breeding methods during the fiveyears 1972 to 1977."The breeding methods by which new cultivarsof groundnuts originate are not unlike themethods used for many other self-pollinatedcrops. They are: (1) introduction and selection;and (2) hybridization or recombination.Backcrosses, multiple crosses and recurrentselection all utilize hybridization. In irradiationbreeding, x-rays or other radiation is used toobtain mutant plants that may be helpful in thedevelopment of improved cultivars.Introduction and SelectionIn the early part of this century the objectives ofgroundnut improvement programs could bemet by line selection from or direct use ofcultivars f r o m other countries. While thismethod is still satisfactory in some cases, suchas the selection of Makulu Red f r o m the Bolivianstrain of groundnuts, Mani Pintar (Smartt 1978),it is inadequate in fulfilling most of the objectivesof many breeding programs.Because of the large investment in equipment,facilities, maintenance, and manpowerrequired in full scale breeding programs, theneed for cooperation between countries orterritories is important. The groundnut improvementprogram at ICRISAT, which is thesubject of the next paper, was designed withthis in mind.Hybridization or RecombinationHybridization and selection a m o n g and withinhybrid lines is currently the most widely usedmethod of obtaining improved groundnut cultivars.Success in breeding hybridization dependson the availability of transferable geneticvariation and will more likely occur if the objectivesare clearly designated, the correct parentsare selected, and if the hybrid populations aremanaged properly and selected successfully.Generally, the better and more adapted parentsgive better segregates or at least increase thelikelihood for production of desirable new recombinations.In any regard, at least one parentin a cross should be a reasonably good performerin the production area to be considered.The rare but greatly superior segregate, h o w -ever, is more likely obtained f r o m crosses betweenplants with more diverse genotypes.The general procedure tor handling segregatinghybrid populations for a self-pollinatingcrop such as groundnut usually involves t h e u s eof the bulk o r t h e pedigree system or numerous59

modifications of the two. Experimental evidenceconcerning the merits of using one of thesystems to the exclusion of the other for breedingself-pollinating crops is contradictory. Ingroundnut breeding, no reports of comparisonswere found and both methods are sometimesused by the same breeder.The pressure to produce new cultivars whichhave pest resistance and other economicallyimportant traits has forced some breeders tomodify their breeding systems in o r d e r t o speedup cultivar development. One such method is amodified pedigree method of selection usingsingle seed descent, which was successfullyused at North Carolina (Wynne 1976).versatility through compositing lines in earlygenerations. Pressures for monocultural productionand uniformity exist throughout the chainfrom farmer to customer. Hammons (1976)reported that the alloploid genetic structure ofA. hypogaea and modified breeding proceduresprovide greater genotypic diversity for theeconomically dominant cultivars in the UnitedStates than that existing in the pure line cultivarsthey replaced. He cautioned, however,that further widening of the genetic base mayrequire changes in cultivar seed certificationstandards and market-grading criteria in theUnited States.Breeding Techniquesfor Specific ObjectivesHigher YieldBy necessity, much of the emphasis ingroundnut breeding throughout the w o r l d isplaced on improving yield. This is partly inresponse to the increased food requirementscaused by an increasing population and limitedland resources and partly due to the everincreasing costs of production. Producinghigher yields per unit area is one of the waysthat the grower has to counteract the costs ofproduction.The general procedures employed in breedingfor higher yields following the hybridizationmethod were reviewed by Norden (1973). Garet(1976) reported the response of eight charactersf r o m a diallel cross of five cultivars. He obtainedheterosis compared with the better parent forseveral yield components. General and specificcombining ability effects and reciprocal effectswere significant for all characters except oilcontent, where general combining ability effectsalone were significant. Additive effectspredominated for all characters except seedyield, where nonadditive effects with d o m i -nance and epistasis were observed.Stability in production over seasons and overa w i d e area is an important attribute of acommercial groundnut cultivar. An objective oft h e Florida groundnut breeding program is tom o l d the cultivar to fit the somewhat specificand restrictive U.S. marketing system, while att h e same time making a conscious effort toavoid depleting the cultivar of its geneticPest ResistanceThere have been recent advances in groundnutbreeding for resistance to pests but many c o m -plex problems still remain. For example, goodresistance to some pests has been found only inthe w i l d species, but these sources ofgermplasm have been largely unavailable becauseof certain inherent barriers to hybridization(Banks 1977; Simpson et al. 1975).Theliteraturesince 1972 concerning breedingfor pest resistance in groundnut is very extensive,and since groundnut pests and pest resistanceare the subjects scheduled for the Workshopt o m o r r o w I will curtail this portion of mypresentation and illustrate with slides thegroundnut breeding methods we are currentlyusing in Florida.ConclusionThe groundnut improvement project in Floridainvolves controlled hybridization followed bypedigreed selection w i t h i n and betweenthousands of different lines. Most peanut crossesdo not result in improved cultivars. Thebasic procedure is to discard the undesirableplants and lines early in the breeding programand save only those with apparent superiority ineconomically desirable characteristics. It is difficultto incorporate desirable characteristicsinto a variety without being overwhelmed byundesirable material. Often the desirablecharacteristic is associated w i t h undesirabletraits.Although the groundnut is difficult to hybridize,making the cross is the least t i m e con-60

suming phase of the breeding program. Thebasic technique for crossing groundnuts hasnot been greatly changed over the years, butnumerous aids and modifications have beenreported (Norden 1980).ReferencesB R A N C H , W. D. 1979. Peanut Farmer 15(4): 9.B A N K S , D . J . 1977. Pages 406 in 1977 Caddo ResearchStation Report. Oklahoma Agricultural ResearchStation, Stillwater, Oklahoma, USA.GARET, B. 1976. Oleagineux 3 1 : 435.H A M M O N S , R. O. 1976. Crop Science 16: 527.N O R D E N , A. J. 1973. Pages 175-208 in Peanuts-cultureand uses. C. T. W i l s o n , ed. American PeanutResearch and Education Association, Stillwater, Oklahoma.N O R D E N , A. J. 1980. Pages 5 1 5 - 5 2 3 in Advances inlegume science. R. J. Summerfield and A. H. Bunting,eds. Royal Botanic Gardens, Kew, EnglandN O R D E N , A. J. 1980. Pages 443-456//7 Hybridization ofcrop plants. W. R. Fehr and H. H. Hadley, eds.American Society of A g r o n o m y , 677 S. Segoe Road,Madison, Wisconsin, 53711.S I M P S O N , C. E., S M I T H , O. D., and HARRISON, A. L. 1975.Pages 6 - 9 in Peanut Production in Texas. TexasAgricultural Experiment Station, College Station,Texas, USA.S M A R T T , J. 1978. Euphytica 27: 605.W Y N N E , J. C. 1976. Proceedings of the AmericanPeanut Research and Education Association 8: 44.61

Groundnut Breeding at ICRISATS. N. Nigam, S. L. Dwivedi, and R. W. Gibbons*Breeding work on groundnuts started in m i d -1976 after the acceptance of the detailed researchproposal (Gibbons 1976) by the GoverningBoard of ICRISAT.The main objective of the program is toproduce high yielding breeding lines or popul a-tions w i t h resistance to the main factors presentlylimiting production.M u c h emphasis has been laid on diseaseresistance breeding — particularly for diseasessuch as leaf spots (Cercospora arachidicola andCercosporidium personation) and rust (Pucciniaarachidis), which are of international importance.Other priorities include breeding forearliness, high yield and quality. Since 1976,several more research projects have beenstarted as and w h e n necessary germplasmbecame available.Groundnut g r o w i n g environments varygreatly not only between but also w i t h i n countries.In addition, there is considerable diversityin the uses to which the crop is put. Consideringthe diverse requirements, emphasis has beenon supplying suitable early generation andadvanced breeding material to cooperators indifferent countries of the Semi-Arid Tropics(SAT) for further selection in situ.Program and ProgressHybridizationThe emasculation and pollination processesused at ICRISAT are basically the same as thosedescribed for Florida by Norden (1973). H o w -ever at Hyderabad, emasculations can be madeas early as 1.30 p.m compared with 5.00 p.m inFlorida. Pollinations are carried f r o m 7.00 a.m to10.00 a.m in Florida, but the highest successrates are achieved at Hyderabad if they aremade around 6.00 a.m.* Plant Breeders and Principal Plant Breeder,G r o u n d n u t Improvement Program, ICRISAT.The standard method of making crosses is touse large pots, containing single parentalplants, which are placed on benches inside aglasshouse or screenhouse. However, it wasrealized that for the large numbers of crosses,which needed to be made for an internationalbreeding program, there were severe limitationsin using this method. In 1977 crossing wastherefore extended to the field. Initial resultswere poor, but by improving insect control andusing an irrigation system to maintain highhumidity at the t i m e of pollination, successrates of over 50% were obtained in therainy season of 1979 and the postrainy seasonof 1979-80. During the current rainy season of1980 the success rate averaged 6 7 % , w i t hsome individuals achieving as high as 9 4 % .During each of the t w o crop seasons some30 000 pollinations are made in the field. Aslarge number of crosses can now be carried out,specific combinations could be made for breedersin national programs w h o have limitedfacilities.Initially the hybridization program mainlyutilized germplasm lines but now after fouryears lines derived at ICRISAT are being used asparents to combine more desirable charactersin breeding populations.Rapid Generation AdvanceThe climatic conditions and the facilities at theICRISAT Center provide opportunities to g r o wt w o full crops in a year. Many of the majorpathogens and insect pests either occur, or canbe induced, during both seasons and thusprovide g o o d opportunities for continuous screening.The problem of postharvest dormancy inVirginia types (sub sp hypogaea) preventingimmediate replanting in the second crop season,has been overcome. The seed is dressedw i t h Ethephon, an experimental preparation inpowder f o r m of an ethylene-releasing com-62

pound (Amchem Products I n a , USA), beforeplanting. In the laboratory more than 9 0 % oftreated seeds germinate within 24 hours. Usingthis technique under field conditions, 7 5 - 8 0 %emergence is obtained within a few days.EvaluationThe advanced breeding populations areevaluated in t w o different environments at theICRISAT Center. The rainfed crop is g r o w nunder low fertility conditions (20 kg P 2 O 5 ) and isnot protected against diseases and insect pests.The irrigated crop is g r o w n at higher fertilitylevels (40 kg P 2 O 5 ) and is protected. Early generationsegregating material, when enough seedis available, is also grown in both environments.Very little material is discarded in earlygenerations. Most of the material is bulked intouniform groups for evaluation and furtherselection at cooperating centers.Stability of yield is important overyears andacross sites. Currently the breeding material isevaluated on a limited scale in different agroclimaticzones in India. An international testingnetwork will soon be set up after the establishmentof outreach programs.Research ProjectsBreeding for Resistanceto Foliar PathogensAt present the work on foliar diseases atICRISAT is restricted to rust and Cercosporaleaf spots as they are worldwide in distributionand cause serious economic losses (Bunting etal. 1974; Hammons 1977; Subrahmanyam et al.1979).S O U R C E S OF R E S I S T A N C E . Rust resistancebreeding started in 1977 with t w o sources ofresistance, PI 259747 and PI 298115. Since thenseveral other sources of resistance have alsobeen incorporated in the breeding program(Table 1).High levels of resistance to leaf spots occurwithin the wild species (Abdou 1966; A b d o u etal. 1974). Leaf spot resistant tetraploid progenies,resulting from interspecific hybridization,will soon become available f r o m theCytogenetics subprogram for utilization by thebreeders (see Singh et al. in this volume).Recently more intensive searches within thecultivated groundnut have shown some usablesources of resistance or tolerance toleaf spot fungi (Sowell et al. 1976; Hassan andBeute 1977; Melouk and Banks 1978; Subrahmanyamet al. 1980b). Many of thegermplasm lines earlier selected for rust resistancehave also shown resistance to lateleaf spot at the ICRISAT Center (Table 2). Severalrust-resistant FESR selections made atICRISAT are also resistant to late leaf spot (Table3). A few rosette-resistant cultivars, such asRMP 91 and RMP 12, have also some resistanceto late leaf spot (Subrahmanyam et al. 1980b).For resistance to early leaf spot, NC 3033 (Beuteet al. 1976) and P1109839 (Hammons et al. 1980)are being utilized in the breeding program.C U R R E N T S T A T U S . The breeding material forrust resistance, other than FESR selections, hasT a b l e 1 . Sources o f rust resistance.Cultivar Source Type ReferencePI 259747 Peru Valencia Mazzani and Hinojosa 1961PI 298115 Introduction to Virginia H a m m o n s 1977Israel f r o m USABunchNC Acc 17090 Peru Valencia Subrahmanyam et al. 1980aEC 76446 (292) Uganda Valencia Subrahmanyam et al. 1980aN C A c c 17133 (RF) S. America Valencia Subrahmanyam et al. 1980bDHT 200 Peru Valencia H a m m o n s 1977FESR selections USDA rust Variable Bailey et al. 1973;nursery,Subrahmanyam et al.Puerto Rico(unpublished data)63

T a b l e 2 .Rust resistant sources also r esistant t o l a t a loaf spot.Cultivar Source Type ReferencePI 259747 Peru Valencia Filho and de Moraes 1977;Subrahmanyam et al. 1980bEC 76446 (292) Uganda Valencia Subrahmanyam et al. 1980bNC Acc 17133 (RF) S. America Valencia Subrahmanyam et al. 1980bFESR selections USDA rust Variable Subrahmanyam et al.nursery,(unpublished data)Puerto RicoT a b l e 3 .Rust a n d l a t e leaf s p o t reactions o fs o m a FESR selections in field screenin g trials a t I C R I S A T C e n t e r , 1 9 7 8 -1 9 8 0 .Mean disease score aSelection Rust Leaf spotFESR 5-P2-B1 2.0 3.0FESR 5-P17-B1 2.0 3.0FESR 7-P13-B1 2.0 3.0FESR 9-P3-B1 2.0 3.0FESR 9-P4-B1 2.0 4.3FESR 9-P7-B1 2.7 3.3FESR 9-P7-B2 2.7 4.3FESR 9-P8-B2 2.0 3.0FESR 9-P12-B1 2.0 2.7FESR 11-P11-B2 2.3 2.7FESR 12-P4-B1 2.0 2.0FESR 12-P5-B1 2.0 2.7FESR 12-P6-B1 2.7 3.7FESR 12-P14-B1 2.0 3.3FESR 13-P12-B1 2.0 2.7TMV-2 (Check) 9.0 9.0a. M e a n score of three seasons on a 1-9 scale.w h e r e 1 - no disease and 9 = 50-100% foliage destroyed.retained for further screening and use in otherbreeding projects.FESR SELECTIONS. Fourteen F3-derived rustresistantlines (FESR 1-14), from a natural crossbetween PI 298115 and an unknown pollendonor in the USDA rust nursery in Puerto Ricowere received at ICRISAT in 1977 (Bailey et al.1973). These lines segregated not only formorphological characters but also for reactionto rust at ICRISAT Center. All the lines wereprogeny-rowed in the next generation whenthey again segregated for reaction to rust. Thisindicated that resistance to rust, though recessive,may not be governed by duplicate loci ashas been reported by Bromfield and Bailey(1972). Since then the material has been advancedto the F 8 generation. Fifteen hundredand forty-six selections are currently beingfinally assessed in the field for yield and rustresistance.Some of the resistant FESR selections,evaluated under rainfed and low-fertility conditions,have yielded more than the releasedIndian cultivars, J-11 and Robut 33-1, and therust-resistant parent, NC Acc 17090 (Table 4).been advanced to the F 6 generation generallyby following pedigree and bulk pedigreemethods. Backcrossing has been adoptedin a few cases. The material is screened inthe field for both rust and leaf spot resistanceusing the infector-row technique developed bySubrahmanyam et al. (1980a). The plants arebroadly classified into resistant and susceptiblegroups based on field scoring using a 1 -9 scale(where 1 = n o disease, and 9 = 5 0 - 1 0 0 % defoliation).Single plants or bulks classified as highyielding but susceptible to foliar pathogens areBreeding for EarlinessGroundnuts, which are earlier maturing thancurrently released cultivars and possess highyield potential together with good quality, willbe extremely useful in areas of the SAT whichhave short growing seasons or where an earlymaturing crop may escape certain pests anddiseases. There is also scope for fitting earlymaturing groundnuts into relay or sequentialcropping systems, particularly in SoutheastAsia by utilizing residual moisture after theharvest of the rice crop (Gibbons 1980).64

T a b l e 4. P e r f o r m a n c e of FESR selectionsunder l o w - f e r t i l i t y a n d rainfed conditi o n s (rainy seeson 1 9 7 9 ) .SelectionsYield(kg/ha)FESR 8-P12-B1-B1-B1 1301FESR 5-P20-B1-B2-B1 1127FESR 9-P5-B1-B1-B1 1076FESR 8-P9-B1-B1-B1 1076FESR 8-P11-B1-B2-B1 1003FESR 8-P13-B1-B2-B1 1001FESR 5-P19-B1-B2-B1 996FESR 8-P3-B1-B2-B1 987NC Acc 17090 a 978Robut 3 3 - 1 * 816J 11 b 524LSD (0.05) 282.7a. Rust-resistant check.b. Susceptible checks.S O U R C E S OF E A R U N E S S . The following cultivarsare presently being utilized in the breedingprogram:Chico — a very early Spanish type, maturingin 7 5 - 8 0 days, commercially unacceptablebecause of extremely small pods; 91176 and91776 — S p a n i s h types, maturing in 8 0 - 8 5days, bred in Tamil Nadu (India); and Robut33-1 — a Virginia type, maturing in 100 days,released in Andhra Pradesh (India).C U R R E N T S T A T U S . The breeding material hasbeen advanced to the F 7 generation by pedigreeor bulk pedigree methods.Several early maturing (100-105 days) selectionshave been identified and are currentlybeing evaluated for yield potential (Table 5).Some of the early flowering material identifiedin the current rainy season is presented inTable 6.The cultivars Robut 33-1 and Chico haveproved to be very good combiners for high yieldin certain cases. Late maturing, high yieldingselections from this project are being utilized inthe high yield and quality project.Breeding for High Yield and QualityThe purpose of this project is to generate baseT a b l e 5. Early m a t u r i n g selections (postrainyseason 1 9 7 9 — 8 0 ) .F 4 generationF 5 generationArgentine x Chico JH 89 x Chico2-5 x Chico JH 171 x Chico28-206 x Chico Dh 3-20 x ChicoSM 5 x Robut 33-1NC Acc 2748 x ChicoTifspan x Robut 33-1 TMV 7 x Chico2-5 x Robut 33-1 Virginia 72R x ChicoVirginia 72R x Robut 33-1 Dh 3-20 x Robut 33-1Table 6.Early flowering selections (rainy season1980).SelectionDays to 75% floweringGeneration (P 1 x P 2) P 1 Selection P 2F 1 Ah 330 x 91176 28 18 17Chico x Ah 330 18 17 28Mani Pinter x 91776 24 17 17Chico x NC Acc 344 18 23 29Robut 33-1 x Jacana 24 21 2091176 x NC Acc 2123 17 23 29F 3 M 13 x 91176 25 21 17Chalimbana x 91176 26 23 17DM 1 x 91176 26 18 17RMP 91 x Chico 23 22 18Ah 114 x 91176 24 20 17material with high yield potential for diseaseresistance programs, and for areas of the worldwhere diseases are not prevalent or protectivemeasures are routinely followed.SOURCES. The following material is beingutilized in the hybridization program: Cultivarsand landraces from different geographicalregions; high yielding and adapted varietiesfrom different countries; and high yieldingbreeding lines developed at ICRISAT.CURRENT S T A T U S . The breeding material hasbeen advanced to F 7 generation using pedigreeor bulk pedigree methods. Several promisingselections are being evaluated for yield potentialin different environments during the currentrainy season.Some of the promising selections made in theF 4 and F 5 generations, during the postrainyseason of 1979-80, are listed in Table 7.65

T a b l e 7 .H i g h y i e l d i n g s e l e c t i o n s (postrainys e a s o n 1 9 7 9 - 8 0 ) .T a b l e 8. F 5 y i e l d e v a l u a t i o n (postrainy season1 9 7 9 - 8 0 ) .F 4 GenerationNC Acc 529 x ShulamitNC-Fla-14 x TG 1Ah 6279 x SpancrossFlorigiant x SM 5GAUG 1 x NC Acc 310Starr x NC Acc 1107Tifspan x SM 5Virginia 72R x NC Acc1107X14-4-B19-B x SM 5F 5 GenerationAh 8254 x JH 62G 37 x S p a n h o maFaizpur 1-5 x NC Acc316NC Acc 63 x TG 17148-7-4-3-12-B x ManfrediNC Acc 2750 x Ah 8189NC Acc 316 x NC Acc310USA 20 x TMV 10SelectionTypeDays tomaturityYield(kg/ha)(Robut 33-1 x NC Acc 2821)F2-B3-B1-B2-B1 SB 121 3827(Robut 33-1 x NC Acc 2698)F2-B2-B1-B1-B1 SB 118 3686(Dh 3-20 x NC Acc 2608)F2-B3-B1-B1-B1 SB 112 3598(2-5 x NC Acc 741)F2-B4-B1-B1-B1 VB 122 3576Robut 33-1 a VB 121 2949J 11 a SB 112 2915LSD (0.05) 634.5a. Standard checks.Five hundred and twelve F 6 bulks wereevaluated in an 8 x 8 x 8 cubic lattice design aswell as in a systematic design, which wassuperimposed over the lattice, during the postrainyseason of 1979-80. The purpose of thetrial was to compare the efficiency of these t w odesigns in evaluation of breeding material. Theresults obtained f r o m the cubic lattice analysisare presented in Table 8. Four breeding linessignificantly outyielded the checks, Robut 33-1and J-11, and 68 more breeding lines were equalin yield to Robut 33-1.A y i e l d trial consisting of progenies of severalplant selections made in the Indian cultivarRobut 33-1 was carried out during the postrainyseason of 1979-80. Eight selections significantlyoutyielded the Robut 3 3 - 1 (Table 9).This cultivar was developed in Andhra Pradesh,India and originated as a selection f r o m amutant or chance out cross in an exotic introduction.New Research ProjectsDuring 1979 and 1980 t h e f o l l o w i n g new breedingprojects were initiated:Breeding for Resistanceto Aspergillus FlavusThree breeding lines, w i t h dry seed resistanceto invasion by the fungus, are presently beingutilized as parents in the hybridization programwith a w i d e range of adapted but susceptiblecultivars. The resistant germplasm lines are PI337394F and PI 337409 (Mixon and Rogers1973) and UF 71513 (Bartz et al. 1978).Breeding for Resistance to Insect PestsT w o germplasm lines, NCAcc 2214 and NCAcc2232, selected for resistance to thrips and jassids(Amin, unpublished data) are being used asparents in an attempt to incorporate resistancein commercially accepted cultivars.Development of Cultivars for VertisolsGroundnuts g r o w n in Vertisols, or dark alluvialsoils, often show symptoms of chlorosis due tolime induced iron chlorosis. Germplasm linesand advanced breeding populations are beingscreened for their reaction to iron, and otherpossible deficiency factors, in Vertisols at theICRISAT Center.Basic StudiesSome basic genetic studies are being conductedin cooperation with research workers inIndia and by postgraduate students at ICRISAT.Studies on breeding methods have shown highgenetic divergence among Spanish and Valenciap a r e n t s s u g g e s t i n g t h e u t i l i t y o fSpanish x Spanish, Spanish x Valencia and66

T a b l e 9 . N a t u r a l hybrid t r i a l (postrainy season 1 9 7 9 - 8 0 ) .Selections f r o m Days to Yield ShellingRobut 33-1 Type maturity (kg/ha) (%)11-7-B1-B1-B1 VB, SB, IB 119 2680 7721-11-B1-B1-B1 SB 119 2683 6610-3-B1-B1-B1 SB 119 2653 767-6-B1-B1-B1 VB, IB 119 2650 7013-6-B1-B1-B1 VB, SB, IB 119 2628 7112-10-B1-B1-B1 VB, IB 119 2620 7550-1-B1-B1-B1 VB 119 2527 7124-16-B1-B1-B1 SB 119 2488 72Robut 33-1 (parent) VB 119 2013 70LSD (0.05) 389.4Valencia x Valencia crosses (Arunachalam etal. 1980).Similar results have been obtained inthe USA by Wynne et al (1970).Uniform non-nodulating lines of groundnutshave been developed through wide crosses andthe genetics of non-nodulation has been determined(Nigam et al. 1980).Some yield trials conducted during rainy andpostrainy seasons at the ICRISAT Center haveshown strong variety x season interactions.This suggests the need of identification ofvarieties for each season. This is particularlyimportant for India where presently 8% of thetotal crop is grown under postrainy conditions.Cooperation with National ProgramsThe breeding material, generated with desirablecharacteristics at ICRISAT, is freely distributedto breeders in national programs toenable them to carry out final selection undertheir local conditions. So far, 2792 selectionshave been supplied to breeders in 14 countries(Table 10). All the breeders, w h o received material,were able to make useful selections out ofbreeding populations supplied. Some selectionshave done exceedingly well in trials inTamil Nadu (India). Another selection, maturingin 85 days, has been f o u n d suitable for summercultivation in Maharashtra.As the breeding program develops, a considerablygreater volume of material will becomeavailable for distribution to any country whichrequests it.T a b l e 1 0 . B r e e d i n g m a t e r i a l s u p p l i e d t oc o o p e r a t o r s b y I C R I S A T , 1 9 7 8 -1 9 8 0 .NumberHigh- Selections Rustyieldingwith resistantCountry selections earliness materialBangladesh 6 14Benin 80 55 68Burma 10 6China 8 2 40Ghana 15 19India 1121 858 288Japan 3Puerto Rico 14Senegal 30 20 40Sri Lanka 17 4 4Tanzania 9 4Thailand 10 20 10Upper Volta 5 6ReferencesA B D O U , Y. A - M . 1966. The source and nature of resista n c e in Arachis s p p to Mycosphaerellaarachidicola Jenk. and M. berkeleyii Jenk. and factorsinfluencing sporulation of these fungi. U n p u b -lished Ph.D. thesis, Department of Plant Pathology,North Carolina State University, Raleigh, NorthCarolina, USA. University Microfilms, Inc. Ann Arbor,Michigan, USA.67

A S O O U , Y. A - M . , GREGORY, W. C, and COOPER, W. E.1974. Sources and nature of resistance to Cercosporaarachidicola Hori and Cercosporidium personatum(Berk and Curtis) Deighton in Arachisspecies. Peanut Science 1: 6 - 1 1 .A R U N A C H A L A M , V., BANDYOPADHYAY, A., N I G A M , S. N.,and G I B B O N S , R. W. 1980. S o m e basic results ofapplied value i n g r o u n d n u t breeding. Pages 1 - 1 9 I NProceedings of the National Seminar on the Applicationof Genetics to Improvement of Groundnut.16-17 July, 1980. School of Genetics, Tamil NaduAgricultural University, Coimbatore-641 003, India.BAILEY, W. K., STONE, E., BROMFIELD, K. R., and GARREN,K. H. 1973. Notice of release of peanut germplasmwith resistance to rust. Virginia Agricultural ExperimentStation , Blacksburg, Virginia and USDA, AgriculturalResearch Service, W a s h i n g t o n , D. C. 3 pp.BARTZ, J. A., NOROEN, A. J., LAPRADE, J. C, and D E -M U Y N K , T . J . 1978. S e e d t o l e r a n c e i n p e a n u t s(Arachis hypogaea L.) to m e m b e r s of the Aspergillusflaws g r o u p of f u n g i . Peanut Science 5: 5 3 - 5 6 .BEUTE, M. K., W Y N N E , J. C, and EMERY, D. A. 1976.Registration of NC 3033 peanut germplasm. CropScience 16: 887.BROMFIELD, K. R., and BAILEY, W. K. 1972. Inheritance toPuccinia arachidls in p e a n u t . P h y t o p a t h o l o g y62: 748 (Abstract)B U N T I N G , A. H., G REGORY, W. C, M A U B O U S S I N , J. R., andR Y A N , J. G. 1974. A p r o p o s a l f o r research ongroundnuts (Arachis) by ICRISAT. pp 1-38. ICRISAT,m l m e o .FILHO, A. S., and de M O R A E S , S. A. 1977. Observacoessobre a incidencia de Cercosporioses em cultivaresde a m e n d o i m (Arachis hypogaea L.) Revista de Agriculture52: 3 9 - 4 6 .GIBBONS, R. W. 1976. Groundnut Improvement Progr a m m e — Priorities and Strategies, pp 1-26.ICRISAT mimeo.G I B B O N S , R. W. 1980. Adaptation and utilization ofgroundnuts in different environments and f a r m i n gsystem. Pages 4 8 3 - 4 9 3 in Advances in LegumeScience, eds. Summerfield and Bunting 1980.H A M M O N S , R. O. 1977. Groundnut rust in the UnitedStates and the Caribbean. Pest Articles and NewsSummaries, 23: 300-304.H A M M O N S , R. O., SOWELL, G. Jr., and S M I T H , D. H. 1980.Registration of Cercospora arachidicola resistantpeanut germplasm. Crop Science 20: 292.H A S S A N , H . N., and B E U T E , M. K. 1977. Evaluation ofresistance to Cercospora leaf spot in peanut g e r m -plasm potentially useful in a breeding program. PeanutScience 4: 78-83.M A Z Z A N I , B., and HINOJOSA, S. 1961. Diferencias varletalesde susceptibllidad a la roya del mani en Venezuela.A g r o n o m i a Tropical 1 1 : 4 1 - 4 5 .M E L O U K , H. A., and B A N K S , D. J . 1978. A m e t h o d ofscreening peanut genotypes for resistance to Cercosporaleaf spots. Peanut Science 5: 112-114.M I X O N , A. C, and ROGERS,K. M. 1973. Peanut accessionsresistant to seed infection by Aspergillusflavus. A g r o n o m y Journal 65: 5 6 0 - 5 6 2 .N I G A M , S. N., A R U N A C H A L A M , V., G I B B O N S , R. W.BANDYOPADHYAY, A., and N A M B I A R , P. T. C. 1980.Genetics of non-nodulation in groundnut (Arachishypogaea L ) . Oleagineux (In press).N O R D E N , A . J . 1973. B r e e d i n g o f t h e c u l t i v a t e dgroundnut (Arachis hypogaea L ) . Pages 182-184inPeanuts-Culture and Uses. American Peanut Researchand Education Association, Inc., USA.S O W E L L , G. Jr., S M I T H , D. H. and H A M M O N S , R. 0 . 1 9 7 6 .Resistance of peanut plant introductions to Cercosporaarachidicola. Plant Disease Reporter 60:494-498.S U B R A H M A N Y A M , P., REDDY, D. V. R., G I B B O N S , R. W.,R A O , V. R., and GARREN, K. H. 1979. Current distributionof groundnut rust in India. Pest Articles andNews Summaries. 25: 2 5 -29.S U B R A H M A N Y A M , P., GIBBONS, R. W., N I G A M , S. N., andR A O , V. R. 1980a. Screening methods and furthersources of resistance to peanut rust. Peanut Science7: 10-12.S U B R A H M A N Y A M , P., M C D O N A L D , D., G I B B O N S , R. W.,N I G A M , S. N. and NEVILL, D. 1980b. Resistance toboth rust and late leaf spot in s o m e cultivars ofArachis hypogaea L. Proceedings, American PeanutResearch and Education Association, USA. (Inpress).W Y N N E , J. C, EMERY, D. A., and RICE, P. W. 1970.Combing ability estimates in Arachis hypogaea L.II.Field performance of Fi hybrids. Crop Science 10:713-715.68

Session 3 — Genetics and BreedingDiscussionT. P. YadavaFor screening material against drought andinsects, do you depend upon natural infestationor some laboratory technique?S. N. NigamDrought screening has not yet been started atICRISAT. Development of a drought screeningtechnique w o u l d be a main priority of thephysiology program, which has recentlystarted. Screening for resistance to insectsdepends to a large degree upon natural infestation,but some useful screening can be donein the screenhouse or laboratory.K. S. LabanaHas ICRISAT got high-quality and highyieldinglines that are better than the M-13spreading cultivar.S. N. NigamHigh yield is not restricted to any one group ofcultivars or botanical type. We have somehigh-yielding runner lines that are better thanM-13 when tested at ICRISAT. Widescale testingof these lines in different environmentshas not been done as yet.A. S. ChahalWhen the 1-9 scale for scoring leaf spot diseasesin groundnut is used, an entry showing50 to 100% defoliation is scored as 9. Someleaves fall due to maturity and some leaveswith even one spot may drop off the plant.W o u l d such leaves be considered under defoliationdue to disease? If not, what is theexplanation?P. SubrahmanyamDefoliation or withering depends upon thecultivar, severity of disease and other environmentalfactors. Susceptible varietieswither very rapidly under high disease pressurewhereas resistant varieties s h o w slowdisease development with perhaps a littlewithering towards maturity. It is comparativelyeasy to select resistant plants.J. S. Chohanin spite of all quarantine efforts, some pathogensdo get moved from country to country.Has any new pathogen been introduced toIndia with groundnut germplasm?V. R. RaoNo. PMV-infected plants have been found inthe Plant Quarantine Glasshouses and wereimmediately destroyed. This serves as anexample of how stringent quarantine resourcesdo result in the interception of diseases.V. RagunathanWas PMV introduced to India through ICRISATgermplasm introductions, or was it alreadypresent in India but had not been detected?R. W. GibbonsPMV has a worldwide distribution. It was firstnoted in India in the north of the country and itwas also reported present in Pakistan someyears ago, so it has probably been here forsometime. Because of the mild symptoms thisdisease has been overlooked in many countries.K. S. LabanaHas ICRISAT got any groundnut lines showingdeterminate flowering?V. R. RaoThe germplasm collection is yet to be checkedfor this character.N. D. DesaiHas ICRISAT any accession available for useas donor parents with drought tolerance anddormancy in Spanish bunch types?69

V. R. RaoScreening for drought tolerance will commenceshortly at ICRISAT but we have somedrought resistant material f r o m Senegal in ourgermplasm collection and we have a few linesof Spanish types showing about 15 dayspost harvest dormancy.A. B. SinghIs there any line resistant to bud necrosis anddry root rot? Are there any resistant or tolerantlines to white grub?P. W. A m i nWe have extensively screened our germplasmcollection but we have not found any lineresistantto bud necrosis. White grub does notoccur in sufficient numbers to do any meaningfulscreening at the ICRISAT Center.B. S. GillI w o u l d like to hear the views of Dr. Nordenregarding plant types that can be utilized inselection for high yield.A. J. NordenA scale has been developed and is used inFlorida. Many factors are involved.S. H. PatilCan Dr. Norden, f r o m his great experience inbreeding improved varieties of groundnut,indicate appropriate hypothetical ideotypesfor obtaining the highest yields in differentbotanical groups of groundnut varieties?A. J. NordenNo, I w o u l d not w a n t to attempt to define ahypothetical ideotype for obtaining best yieldsin the different botanical groups of groundnutcultivars. It is dependent on too many variables,such as the climate, the soils, and theend-use of the crop. For example, the ideotypefor obtaining best yields in a fully mechanizedproduction w o u l d not fit a situation in whichthe crop is produced with hand labor. In theformer, low-growing plants with spreadingprostrate g r o w t h habit and vines entwined arepreferred, but they w o u l d not be the idealwhen the production, harvesting, and pickingare accomplished by hand labor. However, Ithink one could define ideotypes for the differentregions and periods in time.70

Session 4Cytogenetics and Utilization ofWild SpeciesChairman: V. S. RamanRapporteurs: V. R. RaoJ. H. Williams

Cytogenetic Investigations in the Genus ArachisH. T. Stalker*The genus Arachis L. is a New World taxonnative to South America. Species are distributedover a wide range of environments fromsouth of the Amazon to 34°S latitude, and f r o mthe Atlantic shore to the eastern slopes of theAndes. Peanuts are mostly found in sandy soilsin open grasslands or in broken forests (Gregoryet al. 1980). Speciation has generally followeddrainage basins and riverbeds, while thegreatest diversity is found in the headwaters ofthe Paraguay River.Twenty-two species have been described andpossibly 5 0 - 8 0 other distinct taxa are found innature. Gregory et al. (1973) grouped thespecies into seven botanical sections. Intersectionalhybridization is u n c o m m o n while intrasectionalhybrids are more easily producedunder experimental conditions (Gregory andGregory 1979). Barriers to interspecific hybridizationare sometimes great and biosystematicrelationships within some groups, i.e., sectionRhizomatosae, are not fully understood.The cultivated species, Arachis hypogaea L,belongs to the section Arachis along with atleast one other tetraploid (A. monticola Krap etRig.) and 10 diploid species, and hybridizationbetween the cultivated species and other m e m -bers of section Arachis is possible (Smartt andGregory 1967; Raman 1967; Gregory and Gregory1979). When the wild species of sectionArachis are used as female parents, the successrate of producing hybrids is usually greater.Arachis monticola Krap. et Rig. and A.hypogaea are apparently completely compatible.* Assistant Professor, Department of Crop Science,North Carolina State University, Raleigh, NorthCarolina 27650, USA.Note: Paper No. 6625 of the Journal Series of theNorth Carolina Agricultural Research Service,Raleigh, USA. This research w a s partially suppo r t e d b y SEA/CR R e s e a r c h A g r e e m e n t5 9 0 1 - 4 1 0 - 9 - 3 6 7 .Cytogenetic studies over the past four decadeshave included counting the chromosomenumbers of species and their interspecifichybrids, identifying cytologically rare plantssuch as aneuploids, and observing meioticbehavior of species and hybrids.This paper attempts to summarize the accumulatedcytogenetic evidence concerningArachis species and their hybrid derivatives.Gregory and Gregory (1979) and Smartt (1979)have questioned the authenticity of many hybridsreported in the literature, especially thoseclaimed to have been produced by Raman(1976) and Varisai M u h a m m a d (1973a,b,c).Only hybrids of unquestioned identity are thusincluded in this report.Cytogenetic information can conveniently bedivided into studies of somatic and meioticchromosomes, and each major group will bediscussed separately in this report.Somatic ChromosomesChromosome NumbersThe first cytogenetic information presented forArachis was by Badami (1928) w h o reported asomatic chromosome number of 2n = 20 forthe cultivated peanut, A. hypogaea. Other investigatorslater confirmed the true number as2n = 40 (Kawakami 1930; Husted 1931). Gregory(1946) reported a chromosome number of2n = 40 for a wild species, A. glabrata Benth,and one year later Mendes (1947) reportedseveral diploid species in the genus. Poor qualitypreparations have hindered many analyses,and not until Fernandez (1973) publishedtechniques for Arachis chromosomes weremany of these difficulties overcome.Listed in Table 1 are the named species andcorresponding chromosome numbers. AlthoughGregory and Gregory (1979) did not listcollection numbers with many of their parentalassignments, they presented a general pattern73

for diploid and tetraploid species in the genus.Most Arachis species are diploid while a fewmembers of section Arachis and most speciesof section Rhizomatosae are tetraploid. Becausethe tetraploid species of sections Arachisand Rhizomatosae will not hybridize, polyploidyprobably evolved independently in eachof the groups.T a b l e 1 . N a m e d spacies o f Arachis a n d c o r r e s p o n d i n g c h r o m o s o m e n u m b e r .Section/species C h r o m o s o m e ReferenceNoArachisA. batizocoi Krap. et Greg. 20 Smartt and Gregory (1967)A. pusilla (correctly A. duranensis) Krap. et Greg. nom. nud. 20 Krapovickas and Rigoni (1957)A. spegazzinii Greg. et Greg. nom. nud. 20 Gregory and Gregory (1979)A. stenosperma Greg. et Greg. nom. nud. 20 Gregory and Gregory (1979)A. ipaensis Greg. et Greg. nom. nud. 20 Gregory and Gregory (1979)A. he/odes Martius ex Krap. et Rig. 20 Smartt and Gregory (1967)A. villosa Benth. 20 Krapovickas and Rigoni (1949)A. diogoi Hoehne. 20 Mendes (1947)A. cardenasii Krap. et Greg. nom. nud. (10017 GKP) 20 Smartt and Gregory (1967)A. chacoense Krap. et Greg. nom. nud (10602) 20 Smartt and Gregory (1967)A. hypogaea L. 40 Kawakami (1930)A. monticola Krap. et Rig. 40 Krapovickas and Rigoni (1957)ErectoidesA. guaranitica Chod. et Hassl. 20A. tuberosa Benth. 20A. benthami Handro20 Smartt and Gregory (1967)A. martii Handro20A. paraguariensis Chod. et Hassl. 20 Smartt and Gregory (1967)A. oteroi Krap. et Greg. nom. nud. 20 Smartt and Gregory (1967)A. rigonii Krap. et Greg. 20 Krapovickas and Gregory (1960)A. lignosa Chod. et Hassl. (10598) Caulorhizae 20 Smartt and Gregory (1967)A. repens HandroA. pintoi Krap. et Greg. nom. nud.2020Conagin (1963)RhizomatosaeA. burkartii Handro 20 Gregory and Gregory (1979)A. glabrata Benth. 40 Gregory (1946)A. hagenbeckii Harms 40 Krapovickas and Rigoni (1957)ExtranervosaeA. marginata Gard. 20 Mendes (1947)A. lutescens Krap. et Rig. 20 Conagin (1963)A. villosulicarpa Hoehne 20 Mendes (1947)A. macedoi Krap. et Greg. (10127) 20 Smartt and Gregory (1967)A. prostrata Benth. 20 Mendes (1947)AmbinervosaeNone n a m e d 20TriseminalaeA. pusilla Benth. 20Note. nom, nud. = species which are not validly described In the botanical literature.74

AneuploidyPlants of A. hypogaea w i t h 41 c h r o m o s o m e splus a f r a g m e n t w e r e reported by Husted(1936). Spielman et al. (1979) f o u n d a series of4 2 - 4 4 c h r o m o s o m e plants after observingplants g r o w n f r o m small seeds. Other aneuploidswere f o u n d after ionizing radiation(Madhava Menon et al. 1970; Patil 1968; Patiland Bora 1961) and chemical treatments (Ashriet al. 1977).Aneuploidy in Arachis is c o m m o n l y observedafter colchicine treatment of treating interspecifichybrids. Smartt and Gregory (1967)and Spielman et al. (1979) reported a range ofchromosome numbers in colchicine-treatedA. hypogaea x diploid section Arachis hybrids.After several generations of selfing a 6x(A. hypogaea x A cardenasii Krap. et Greg. nom.nud.) interspecific hybrid, Simpson (1976) reported progeny w i t h c h r o m o s o m e numbersranging f r o m 3 2 - 4 8 . However, w h e n selectingfor agronomic fitness. Stalker et al. (1979) f o u n dall selected plants in the population had 40chromosomes. Thirty-one and 32-chromosomeplants also resulted f r o m intersectionalhybridization of 4x (section ErectoidesxsectionErectoides)x2x section Arachis species (Stalker1978; in review). Trispecific hybrids of A.hypogaeax4x section Arachis amphidiploidsalso resulted in a f e w aneuploid progeny(Stalker, unpublished data).A l t h o u g h a n u m b e r of aneuploid plants havebeen d o c u m e n t e d , complete aneuploid seriesof g e n o m e s have not been produced. Sets of A.hypogaea aneuploids need to be created andmaintained so that genetic analyses of c h r o m o -somes can be performed. Even t h o u g h aneuploidsrecovered after interspecific hybridization(and recovered 40-chromosome interspecifichybrids) are suspected of having w i l d speciesc h r o m o s o m e s , t h e cytological make-up of hybridderivatives is unknown. Karyotyping w i l dand cultivated species c h r o m o s o m e s alongw i t h maintaining cytologically unique plantswill aid in t h e utilization of aneuploids.Chromosome MorphologyThe c h r o m o s o m e s of A. hypogaea are smallw i t h mostly median centromeres (Chimpu1930). A l t h o u g h karyotyping Arachis c h r o m o ­somes is d i f f i c u l t several distinctive c h r o m o -somes have been f o u n d . Husted (1933, 1936)reported one c h r o m o s o m e pair w h i c h was distinctlysmaller than other chromosomes of thecultivated species (A chromosomes) and onepair w i t h a secondary constriction (B c h r o m o -somes). He analyzed the c h r o m o s o m e s ofseveral varieties but was unable to detect differences.Babu (1955) f o u n d several different typesof secondary constrictions in 14 A. hypogaeavarieties. Tennessee Red was the only varietyw i t h o u t a secondary constriction in his study.D'Cruz and Tankasale (1961) w e r e also able tocytologically distinguish four A. hypogaea varietiesbased on centromere positions andc h r o m o s o m e lengths.The w i l d species A. villosa var correntinaBenth has a small (A) c h r o m o s o m e similar tothat f o u n d in A. hypogaea (Raman 1959;Smartt 1965). Smartt (1965) observed the smallA chromosomes in several other members ofsection Arachis; this distinctive pair was notpresent in t h e section Erectoides species A.paraguariensis Chod. et Hassl. (9646 GKP).F r o m p h o t o m i c r o g r a p h s p r o d u c e d b yKrapovickas et al. (1974), A. batizocoi Krap. etGreg, apparently did not have the A c h r o m o -some f o u n d in other section Arachis species.Smartt et al. (1978) later confirmed the absenceof this distinctive c h r o m o s o m e pair in A.batizocoi.The c h r o m o s o m e s of eight section Arachisspecies range in length f r o m 1 - 4 µ m in themetaphase stage of mitosis (Stalker and Dalmacio,in review). Each of the 10 h o m o l o g o u schromosomes of each species studied wasidentifiable based on centromere position,length, secondary constrictions, and differentialstaining of heterochromatic and euchromaticregions of the chromosomes. Arachis batizocoihad a unique karyotype with 1 submedian (S/Larm=0.33-0.64) and 6 slightly submedian (S/Larm=0.65-0.79) chromosomes and a secondaryconstriction on the long arm of c h r o m o s o m e 2.Arachis cardenasii had many slightly submedianchromosomes and was t h e only speciesobserved w i t h secondary constrictions on t w oc h r o m o s o m e s (5 and 10). Most of t h e otherspecies of section Arachis mostly had medianor slightly submedian chromosomes. Secondaryconstrictions were on t h e median c h r o m o ­somes of A. chacoense Krap. et Greg. nom. nud.,A. duranensis Krap. et Greg. nom. nud., and A.stenosperma Greg, et Greg. nom. nud., w h i l e75

none were found for species A. villosa, A.correntina Krap. et Greg. nom. nud., or A.spegazzinii Greg, et Greg. nom. nud. Afterc o m b i n i n g fertility data w i t h karyotypeanalyses, Smartt et al. (1978a,b) and Stalker andDalmacio (in review) proposed that sectionArachis has t w o distinct genomes. Most specieshave the A genome w h i l e A batizocoi has the Bgenome. Based only on karyological evidence,subgroups of the A genom e w e r e also proposedas f o l l o w s : A 1 =A. cardenasii; A 2 =A.chacoense,A. duranensis, and A. stenosperma;and A 3 = A. correntina, A. spegazzinii, and A.villosa (Stalker and Dalmacio, in review). Table2 lists the eight species of section Arachisanalyzed and corresponding c h r o m o s o m emorphological traits (Stalker and Dalmacio, inreview).Chromosome BehaviorSpaciesAll diploid species of the genus Arachis have 10bivalents and regular meiosis (Resslar and Gregory1978; Smartt et al. 1978a,b; Raman 1976;Stalker and Wynne 1979). Tetraploids of sectionArachis, A. hypogaea, and A. monticola, alsobehave cytologically like diploids and usuallyhave 20 bivalents (Raman 1976). However, tetraploidmembers of section Rhizomatosae mayhave 1 - 4 multivalents per cell (Raman 1976).Many intraspecific hybrids between subspeciesof A. hypogaea produce sterile or " m u t -ant" progeny in the second or later generations.Genetical or cytological divergence amongsubspecif ic groups may offer an explanation forthe sterility. Husted (1936) observed bivalentsplus a f e w univalents, trivalents, and quadrivalentsin Virginia x Spanish varietal hybrids.Both Husted (1936) and Raman (1976) concludedthat structural differences may be presentbetween the t w o botanical types. Tofurther characterize the meiotic behavior ofintraspecific hybrids of A. hypogaea, Stalker(unpublished) cytologically analyzed parentsand crosses of Spanish, Valencia, and Virginiavarieties (Table 3). The parents in the studyrepresented five gene centers of SouthAmerica. Bivalents w e r e observed in most parentsand hybrids, but univalents and multivalentsw e r e also recorded at a low frequency.Only one hybrid combination, Valencia x Virginia,had a relatively high frequency of univalents(Table 3) which may indicate structuraldifferences between t h e t w o botanical varieties.Further analyses, especially of somaticchromosome morphology, are needed beforeconclusions concerning specific c h r o m o s o m edifferences among subspecific groups can bemade.T a b l e 2. C h r o m o s o m e v a r i a t i o n a m o n g s e c t i o n Arachis species of t h e g e n u s Arachis (abstractedf r o m S t a l k e r a n d D a l m a c i o , i n r e v i e w ) .ChromosomesW i t h Slightly Total RatioProposed secondary Sub- sub- g e n o m e chrornSpecies g e n o m e s * constriction median m e d i a n length 10:1A. cardenasii A 1 5,10 2,4,5,6, 28.05 .63A. chacoense A 2 7 77,9,102,5,9,10 29.03 .56A. duranensis A2 6 6 5,9 26.48 .41A stenosperma A 2 5 5,6,9,10 27.46 .44A. correntina A 3 9 1,2,5 29.89 .51A. spagazzinii A 3 9 10 24.29 .47A. villosa A3 9 7,10 25.72 .50A batizocoi B 2 1 2,3,4,5,6,925.49 .64a. S u b g r o u p s at t h e A g e n o m e (A1, A 2 a n d A 3) w e r e p r o p o s e d based on karyological analyses and do not necessarily correspondw i t h plant habit n o r h y b r i d fertility.76

Table 3. Melotic behavior of Spanish, Valancia and Virginia varieties of A. hypogaea and theirintraspecific hybrids.NumberAvg chrom assoc/cellIdentity Genotype Plant Cell I II III IVSpanish (Sp)Valencia (Val)Virginia (Va)34335375125750.010.0819.8519.8619.960.050.06Sp x SpVal x Val3356125150 0.0719.9019.89 0.010.050.02Sp x ValVal x Sp43561111750.140.1519.8919.860.01 0.010.01Val x VaVa x Val4151180250.510.0819.5919.960.01 0.08Sp x VaVa x Sp4162150500.070.1219.9319.940.01Meiotic Behavior of InterspecificHybridsMeiosis in F 1 hybrids between the t w o tetraploidspecies of section Arachis, A. hypogaea andA. monticola, is regular, and 20 bivalents areusually observed in pollen mother cells. Arachishypogaea and A. monticola apparently havethes a m e g e n o m e s and gene exchange freelyoccurs in hybrids.Arachis hypogaea also hybridizes w i t h diploidmembers of section Arachis. The F 1 hybridsare sterile and cytological analyses reveal thatunivalents and bivalents are the most c o m m o nchromosome configurations in pollen mothercells. The frequency of trivalents in meiotic cellsis dependent upon the wiId species parent usedin crosses. For example, Smartt (1965) reportedan average of 0.95 trivalents for A. hypogaea xA. villosa var. correntina, 2.15 trivalents for A.duranensis hybrids, and 3.40 trivalents when A.helodes was used as a parent. Meiotic analysesof triploid hybrids in Arachis do not reveal withwhich genome(s) the w i l d species were paired.At least in cells w i t h trivalents, cultivatedcultivated,and cultivated-wild species chromosomeassociations occurred. Assuming A.hypogaea has t w o distinct genomes, the greaterthe chromosome homology between thew i l d and cultivated species, the fewer trivalentsw o u l d be expected because homologouspairing among genomes w o u l d be restricted bythe relatively rapid synapsis of homologues. Adetailed analysis of pairing relationships betweenA. hypogaea varieties and the sectionArachis diploid species would greatly add to ourunderstanding of genomic relationships amongthe species.Fertility can be restored after colchicinetreatment of triploid interspecific hybrids. In 6x(A. hypogaea x A. cardenasii) hybrids, meiosisis apparently irregular with up to 32 univalentsformed during meiosis in 60-chromosomeplants (Spielman et al. 1979). The meioticallyunstable gametes are apparently eliminatedbefore seed set, however, because progenyfrom these hybrids are stable at the 60-chromosome ploidy level (P. Moss, personalcommunication). In 6x hybrids between A.hypogaea and A. chacoense between 2 and 18univalents per cell were observed (Companyand Stalker, unpublished). Since every chromosomehas a homologue in the 6x plants, genescausing asynapsis must be present. Companyand Stalker (unpublished) also observed progenyf r o m 60-chromosome A. hypogaea xchacoense x cardenasii, and x batizocoi hybridderivatives and the offspring are apparentlystable at the 60-chromosome level. In the secondto fifth generations after self-pollinating 6x(A. hypogaea x A. batizocoi) hybrids, the usualcytological configuration is bivalents and m e i o -tic processes appear normal (Stalker, unpublished).Since strong selection pressure for77

viable seeds occurs in seed nurseries to maintainthe germplasm, corresponding pressuresare exerted in the interspecific hybrids for normalmeiosis and viability. Diploidization w o u l dthus be expected to occur rapidly in polyploidinterspecific hybrids.Meiosis of most diploid x diploid sectionArachis interspecific hybrids is normal and 10bivalents are observed in F 1 pollen mother cells(Raman and Kesavan 1962; Resslar and Gregory1979; Stalker and W y n n e 1979). The exceptionis w h e n A. batizocoi is used as a parent.These F 1 hybrids are sterile and have irregularmeiosis (Gibbons and Turley 1967; S m a r t t e t a l .1978a,b; Stalker and W y n n e 1979). As indicatedin the section concerning c h r o m o s o m e m o r -phology, A. batizocoi has c h r o m o s o m e m o r -phologies different f r o m the other observedspecies of section Arachis, and meiotic andmitotic analyses confirm the presence of t w ogenomes in section Arachis. Few analyses ofinterspecific hybrids in other botanical sectionsof the genus have been recorded, although inone section Erectoides x section Erectoideshybrid (10034 GKP x 9646 GKP), the F 1 wassterile and meiotic cells averaged 1.2 univalentsand 9.4 bivalents per cell (Stalker, unpublished).Structural differences are apparently found betweenspecies of sections other than sectionArachis.Amphidiploids produced f r o m diploid fertilesection Arachis interspecific hybrids are malefertile,but most plants do not produce manyseeds. Amphidiploids behave meiotically eitheras diploids w i t h 20 bivalents or may have asmany as 9 quadrivalents per pollen mother cell(Stalker and Dalmacio, unpublished). Based onobservations of only a limited number of plants,trispecific A. hypogaeax4x section Arachisamphidiploids have 4 0 - 6 0 % fertility and manyunivalents per pollen mother cell. Meiosis isirregular with m a n y laggards and bridges(Stalker, unpublished). The analysis of trispecifichybrids is compatible with previousevidence for A. hypogaea having t w o genomesw i t h one being the A g e n o m e of many sectionArachis diploid species.Intersectionsl hybrids are difficult to produceand cytological analyses are correspondinglyless frequent. Stalker (1978; in review) reportedmeiotic c h r o m o s o m e behavior in (4x sectionErectoides amphidiploids x 2xsection Arachis)F 1 h y b r i d s . T h e s t e r i l e A rigonii (10034GKP) x Arachis sp 9841 GKP F 1 hybrid was colchicinetreated after which a fertile amphidiploidwas found. This plant was hybridized with A.stenosperma (410 HLK) and A. duranensis (7988K). The resulting 3 0 - 3 2 c h r o m o s o m e offspringhad mostly univalents and bivalents plus a fewtrivalents. The author concluded that intersectionalc h r o m o s o m e associations were presentin the hybrids and possibly a c o m m o n genomewas present between sections Arachis andErectoides. Complex section Erectoides (E)xsection Rhizomatosae (R) hybrids producemostly bivalents during meiosis (Stalker, unpublished).Because of the ploidy levels andcomplexities of most existing hybrids, conclusionsconcerning intersectional chromosomeassociations are difficult to make. However, inone hybrid combination 4x[GKP 10034 (E)xGKP9841 (E)] x4x [GKP 9841 (E)xGKP 9570 (R)] thenormally 20 bivalents observed, most probablyrepresented intersectional chromosome associations(Stalker, unpublished).D i s c u s s i o nCareful analyses of section Arachis chromosomeshave revealed enough variation to identifythe 10 homologues. As chromosomes beco m e more condensed they are proportionatelymore difficult to karyotype. At least t w ogenomes exist in the section Arachis. The Agenome includes most species of the sectionand the known B genome currently consists ofonly A. batizocoi. At least five species can becytologically identified in section Arachis;another three cytologically similar species (A.correntina, A. spegazzinii, and A. villosa) canonly be distinguished after many cells areanalyzed.interpretation of chromosome pairing relationshipsof diploid interspecific hybrids is generallystraightforward. In section Arachis, A.batizocoi hybrids have irregular meiosis and aresterile. All other diploid interspecific hybridsinvolving species of this section thus faranalyzed have 10 bivalents at metaphase I.Semisterility is c o m m o n in most interspecifichybrids even though meiosis is regular. M o r evariation in c h r o m o s o m e morphology wasfound in somatic section Arachis species thanexpected, based on previous observations ofmeiotic chromosome associations in pollenm o t h e r cells. H o m o l o g o u s c h r o m o s o m e78

pairing must occur at a high frequency ininterspecific hybrids of section Arachis.Polyploidy is naturally present in t w o sectionsof the genus and colchicine treatment hasresulted in induced polyploids in several others.Analyses of chromosome numbers to identifyhybrids and then to determine intergenomicchromosome relationships in hybrids with2 x = 4 0 to 60+ are desirable. Interpretation ofc h r o m o s o m e pairing relationships in polyploidsis sometimes difficult. Because of thesmall chromosome size, meiotic Arachischromosomes are extremely difficult to identify.While multivalents in tetraploids may indicateintergenomic homologies, mostly only oneor t w o quadrivalents per cell are observed.Also, the same or different c h r o m o s o m e maybe pairing in different cells so the amount ofpossible gene exchange is difficult to determinein most hybrids. Bivalent formation in polyploidsgenerally indicates distinct genomes andlimited intergenomic interaction. However,when only bivalents are present, conclusions asto interaction cannot be easily drawn. Whileformation of pentavalents or hexavalents inallohexaploids indicates homology among allthree genomes, formation of only quadrivalentsw o u l d not prove nor disprove genomic relationships.Based on the extensive hybridization programconducted by Gregory and Gregory (1979),at least five genomes have probably evolved inthe genus Arachis, including: AM (Ambinervosae),C (Caulorhizae), E (Erectoides), EX (Extranervosae),and T (Triseminalae). Tetraploidmembers of section Rhizomatosae hybridizewith sections Arachis and Erectoides in relativelyhigh frequency. Rhizomatosae may thushave a c o m m o n g e n o m e w i t h Arachis andErectoides. The relationships are somewhatconfusing because section Arachis probably didnot evolve f r o m section Rhizomatosae, or viceversa. Present evidence indicates that sectionArachis has t w o genomes and members w i t heither the A genome (i.e., A. duranensis or Aspegazzinii) or w i t h the B genome (i.e., A.batizocoi) will hybridize with the same sectionRhizomatosae collections. However, othermembers with the A genome (i.e., A villosa, A.correntina, A.cardenasii, and A. chacoense)w i l l n o t h y b r i d i z e w i t h t h e s a m e sectionRhizomatosae collections (Gregory and Gregory1979). The crossing relationships along w i t hkaryotyping data indicate a considerableamount of diversity exists within sectionArachis species. For species outside sectionArachis, the genomes are not cytologically verifiednor completely identified. Many questionspertaining to chromosome pairing in hybrids,causes for incompatibilities (failures of hybridsmay be due in part to single genes conditioninggametophytic or sporophytic incompatibilities),and further biosystematic analyses to identifyadditional viable hybrids will add considerablyto the understanding of species relationships.Progenitor species of A. hypogaea are as yetunidentified. Present indications are that thecultivated species combines the A and Bgenomes. However, only after extensivecytological analyses will questions of ancestrybe clarified. Identifying progenitors of A.hypogaea is more than an academic question inthe genus. If progenitor species were used ininterspecific hybrid combinations, then pairingand gene exchange w o u l d be more likely tooccur. For example, if 4x amphidiploid hybridswere crossed w i t h the cultivated species, andone of the species was an ancestor of A.hypogaea, then pairing between the cultivatedand wild species w o u l d more likely occuramong all chromosomes in the trispecific hybrid.Cytogenetic i n f o r m a t i o n has steadily accumulatedd u r i n g the past 40 years. M a n yspecies still need to be collected and also suchbasic information as chromosome numbers reco r d e d . For the cultivated and a f e w w i l dspecies, especially in section Arachis, the usefulcytogenetic information will soon help in manipulatingchromosomes for improvement ofpeanut varieties.ReferencesASHRI, A., OFFENBACH, R., CAHANER, A., and LEVY, A.1977. Transmission of acriflavin induced trisomicmutants affecting branching pattern in peanuts, Ahypogaea L. Zeitschrift fur Pflanzenzuch 79: 220-228.BABU, C. N. 1955. Cytogenetical investigations ongroundnuts. I. The somatic chromosomes. IndianJournal of Agricultural Science 25: 41-46.79

B A D A M I , V. K. 1928. Ph.D. thesis (unpublished). Universityof Cambridge, England. Cited in H. Huntedand H. M. Leake, 1933. Recent Advances in AgriculturalPlant Breeding, Blakiston, Philadelphia.C O N A G I N , C. H. T. M. 1963. N u m e r o de cromosomasdas especies s e l v a g e m s de Arachis. Bragantia22: 1 2 5 - 1 2 9 .D ' C R U Z and T A N K A S A L E , M. P. 1961. A note on c h r o m o -some complement of four groundnut varieties. IndianOilseeds Journal 5: 5 8 - 5 9 .FERNANDEZ, A. 1973. El acido lactico c o m o fijadorcromosomico. Bol. Soc. Argent. Bot. 15: 2 8 7 - 2 9 0 .G M I M P U , V. 1930. Recharches cytologiques sur lesgenes: Hordeum, Acacia, Medicago, Vitis et Quercus.A r c h . D'Anat. Microsc. 26: 136-234.G I B B O N S , R.W., and T U R L E Y , A. C. 1967. Grain legumepathology research team. Botany and Plant Breeding.Pages 8 6 - 9 0 in Annual Report of the AgriculturalResearch Council of Central Africa.GREGORY, M. P., and GREGORY, W. C. 1979. Exoticgermplasm of Arachis L. interspecific hybrids. Journalof Heredity 70: 185-193.GREGORY, W. C. 1946. Peanut breeding program unde r w a y . Pages 4 2 - 4 4 / n Research and Farming, 69thA n n u a l Report, North Carolina Agricultural ExperimentStation.K A W A K A M I , J. 1930. Chromosome numbers in Leguminosae.Botanical Magazine (Tokyo) 44: 319-328.K R A P O V I C K A S , A., a n d R I G O N I , V . A . 1949.C h r o m o s o m a s de una especies silvestrede Aachis.Idia Buenos Aires 2: 2 3 - 2 4 .KRAPOVICKAS, A., and R I G O N I , V. A. 1957. Nuevas especiesde Arachis vinculadas al problem del origendel mani. Darwinians 1 1 : 4 3 1 - 4 5 5 .KRAPOVICKAS, A., and GREGORY, W. C. 1960. Arachisrigonii nueva especie silvestre de mani. Revista deinvestigaciones Agricolas Buenos Aires 14: 1 5 7 -160.KRAPOVICKAS, A., FERNANDEZ, A., and S E E L I G M A N , P.1974. Recuperacion de la fertllldad en un hibridointerspecifico esteril de Arachis (Leguminosae)Bonplandla 3: 129-142.M A D H A V A M E N O N , P., R A M A N , V . S., and K R I S H N A S W A M I ,S. 1970. An x-ray induced m o n o s o m l c in groundnut.Madras Agricultural Journal 57: 8 0 - 8 2 .M E N D E S , A. J. T. 1947. Estudos citologicos no generoArachis. Bragantia 7: 2 5 7 - 2 6 7 .PATIU, S. H. 1968. Cytogenetics of x-ray i n d u c e daneuploids in Arachis hypogaea L. Canadian Journalof Genetics and Cytology 10: 545-550.PATIL, S. H., and BORA, K. C. 1961. Meiotic abnormalitiesinduced by x-rays in Arachis hypogaea. IndianJournal of Genetics 2 1 : 5 9 - 7 4 .GREGORY, W. C, GREGORY, M. P., KRAPOVICKAS, A.,S M I T H , B. W., and Y A R B R O U G H , J . A. 1973. Structuresand genetic resources of peanuts. Chapter 3 inPeanuts — culture and uses. American Peanut Researchand Educational Association, Stillwater, Oklahoma74074 USA.GREGORY, W. C, KRAPOVICKAS, A., and GREGORY, M. P.1980. Structure, variation, evolution, and classificationin Arachis. Pages 4 6 9 - 4 8 1 in S u m m e r f i e l d andBunting (eds.), Advances in Legume Science.H U S T E D , L. 1931. C h r o m o s o m e numbers in species ofpeanut Arachis. American Naturalist 65: 4 7 6 - 4 7 7 .H U S T E D , L. 1933. Cytological studies of the peanutArachis I. C h r o m o s o m e number and m o r p h o l o g y .Cytologia 5: 1 0 9 - 1 1 7 .H U S T E D , L. 1936. Cytological studies of the peanutArachis II. C h r o m o s o m e number, m o r p h o l o g y andbehavior and their application to t h e origin of cultivatedf o r m s . Cytotogla 7: 3 9 6 - 4 2 3 .R A M A N , V. S. 1959. Studies in the genus Arachis VII. Anatural interspecific hybrid. Indian Oilseeds Journal3: 2 2 6 - 2 2 8 .R A M A N , V. S. 1976. Cytogenetics and breeding inArachis. Today and T o m o r r o w ' s Printers and Publishers,New Delhi, India, 84 pages.R A M A N , V. S., and K E S A V A N , P. C. 1962. Studies on adiploid interspecific hybrid in Arachis. Nucleus (Calcutta)5: 123-126.RESSLAR, P. M., and GREGORY, W. C. 1979. A cytologicalstudy o f t h r e e diploid species of the genus Arachis L..Journal of Heredity 70: 1 3 - 1 6 .S I M P S O N , C. E. 1976. Peanut breeding strategy toexploit sources of variability f r o m w i l d Arachisspecies. Proceedings of the American Peanut Researchand Education Association 8: 87 (Abs.).S M A R T T , J. 1965. Cross-compatibility relationships betw e e n the cultivated peanut Arachis hypogaea L.and other species of t h e g e n u s Arachis. Ph.D. thesis,North Carolina State University. No. 65,8968. Uni-8 0

versity Microfilms International, A n n Arbor, Michiga n , USA.S M A R T T , J. 1979. Interspecific hybridization in the grainlegumes — A review. Economic Botany. 33: 3 2 9 -337.S M A R T T , J., and GREGORY, W. C. 1967. Interspecificcross-compatibility between the cultivated peanutArachis hypogaea L and other m e m b e r s of thegenus Arachis. Oleagineux 22: 4 5 5 - 4 5 9 .STALKER, H. T. No date. Intersectional hybrids in thegenus Arachis between sections Erectoides andArachis. Crop Science (in review).STALKER, H. T., and D A L M A C I O , R. NO date. Chromoso m e s of Arachis s p e c i e s , s e c t i o n Arachis(Leguminosae). Journal of Heredity (in review).STALKER, H. T., and W Y N N E , J. C. 1979. Cytology ofinterspecific hybrids in section Arachis of peanuts.Peanut Science 6: 110-114.S M A R T T , J., G REGORY, W. C, and GREGORY, M. P. 1978a.The genomes oft Arachis hypogaea L.I. Cytogeneticstudies o f p u t a t i v e g e n o m e d o n o r s . Euphytica27: 6 6 5 - 6 7 5 .STALKER, H. T., W Y N N E , J. C, and C O M P A N Y , M. 1979.Variation in progenies of an Arachis hypogaea xdiploid w i l d species hybrid. Euphytica 28: 6 7 5 - 6 8 4 .S MARTT, J . , G REGORY, W. C, and G REGORY, M. P. 1978b.The genomes of Arachis hypogaea. 2. The implicationsin interspecific breeding. Euphytica 27: 6 7 7 -680.S P I E L M A N , F. V., B U R G E , A. P., and M o s s , J. P. 1979.C h r o m o s o m e loss and m e i o t i c behavior in interspecifichybrids in the genus/lrac/7/s L. and theirimplications in breeding for disease resistance. 2.Pflanzenzuchtg 83: 236-250.S T A L K E R , H. T. 1978. Cytological analysis of Erectoidesx Arachis intersectional hybrids. Proceedingsof the American Peanut Research and EducationAssociation 10: 62.V A R I S A I M U H A M M A D , S. 1973a. Cytogenetical investigationsin the genus Arachis L. I. Interspecific hybridsbetween diploids. Madras Agricultural Journal60: 323-327.V A R I S A I M U H A M M A D , S. 1973b. Cytogenetical investigationsin the genus Arachis L. II. Triploid hybridsand their derivatives. Madras Agricultural Journal60: 1414-1427.V A R I S A I M U H A M M A D , S. 1973c. Cytogenetical investigationsin the genus Arachis L. III. Tetraploid interspecifichybrids and their derivatives. MadrasAgricultural Journal 60: 1428-1432.81

Utilization of Wild Arachis Species at ICRISATA. K. Singh, D. C. Sastri and J. P. Moss*One of the possibilities for increasing the yieldof g r o u n d n u t , particularly in the Semi-AridTropics, is breeding varieties w i t h resistance topests and diseases. S o m e progress has beenmade in this field, but the improvements thatcan be made by breeders are limited by theavailability of genes w i t h i n A. hypogaea. Collectionsof w i l d species f r o m South America havemade available a wider range of genes, especiallygenes for disease resistance. The richnessof Arachis germplasm collection offers a greatopportunity for anyone interested in the improvementof this crop (Bunting et al. 1974,Simpson 1976; Smartt et a I. 1978a, b; Gregoryand Gregory 1979).However the c y t o t a x o n o m y of the genusArachis is such that it is difficult for a breeder touse wild species in groundnut improvement(Gregory and Gregory 1979; Moss 1980; Stalker1980). The t w o major constraints to utilizationof w i l d species are differences in ploidy leveland incompatibility between some wild speciesand A. hypogaea. The small size of chromosomesof Arachis and the difficulty experiencedby some workers in making good cytologicalpreparations has deterred many people fromattempting cytogenetic techniques in the improvementof Arachis, despite their successfulapplication to many other crop plants, especiallyw h e a t a n d t o b a c c o . T h e g r o u n d n u tcytogenetics program at ICRISAT has attemptedto overcome these difficulties, and to produceinterspecific hybrids and to manipulatethe ploidy level to produce tetraploid lines incorporatingdesirable characters w h i c h canthen be utilized by breeders in the improvementof groundnut.The program on utilization of wild species inArachis was initiated at Reading University(U.K.) w i t h three species w h i c h were known tocross w i t h A. hypogaea and were resistant to* Cytogeneticists, Groundnut Improvementg r a m , ICRISAT.Proleafspots. These were A. cardenasii Krap. andGreg., nomen n u d u m , A. chacoense Krap. andGreg., nomen n u d u m , and Arachis species Coll.HLK 410 which were reported as i m m u n e toCercosporidium personatum, highly resistantto Cercospora arachidicola, and resistant toboth (Abdou 1966; Sharief 1972; A b d o u et al.1974; Hammons, personal communication).The groundnut cytogenetics program atICRISAT was initiated in April 1978 with theobject of making the fullest possible use of thegenus Arachis. Cooperation with the GeneticResources Unit, pathologists, entomologists,and microbiologists has increased the numberof wild species at ICRISAT and our knowledgeof the desirable genes which they contain.Cytogenetic analysis provides information toimprove the efficiency of incorporation of wildspecies genes into A. hypogaea. Thetechniqueshave been described by Singh et al. (1980).In addition to A. hypogaea, section Arachiscontains one other tetraploid. A. monticola, andseveral diploid species. All these species arecross compatible w i t h A. hypogaea (Smartt andG r e g o r y 1967; Stalker 1980). Nine d i p l o i dspecies and the t w o tetraploids have beenstudied in detail and a chromosome with a secondaryconstriction and a small satellite seen aschromosome 3 in A. villosa, A. correntina, A.chacoense, and Arachis species Coll. No. 10038,and a chromosome with a secondary constrictionand a large satellite seen in A. batizocoi andin A. duranensis as chromosome 2, in Arachisspecies 338280 as chromosome 6 and in Acardenasii as chromosome 9. Chromosomeswith secondary constrictions had only beenreported previously in A. batizocoi. The smallpair of chromosomes in A. cardenasii are largerthan in the remaining species but still smallerthan the smallest chromosomes of A. batizocoi.A. monticola and A. hypogaea are closekaryomorphologically, though A. monticola hast w o pairs of chromosomes w i t h secondaryconstrictions whereas A. hypogaea has onlyone, and the chromosome with a secondary82

constriction in A. cardenasii is comparable toone of those of A. monticola and that of A.hypogaea.M a h a l a n o b i s D 2 analysis and c a n o n i c a lanalysis, using the arm ratio of each of the tenchromosomes of the diploid taxa investigated,resulted in t w o clusters within these. A.batizocoi is the only species in one of theseclusters; there are eight taxa in the other cluster,which can be further subdivided (Fig. 1).All the species of the section Arachis arecross-compatible, and differences in crossabilityare too small to be satistically significant. Allthe available nine diploid taxa have been crossedin all possible combinations and a largen u m b e r of F 1 h y b r i d s have been analysedcytologically. Results from these studies substantiateour grouping of the diploid species.The F 1 hybrids resulting f r o m the cross of t w ospecies belonging to the t w o different clustersshow a high frequency of univalents and a highpollen sterility, while F 1 hybrids between t w ospecies of the same cluster show a low frequencyof univalents and a low pollen sterility.D 2 distances among species of section ArachisA. villosaA. correntinaA. chacoenseA. sp 263133(SL)A. sp 263133(LL)A. sp 338280A. duranensisD 2 = 0 . 3 7 9 - 0 . 8 8 3A. cardenasiiCluster IAverage intracluster D 2 = 0.335Figure 1.Cluster diagram.D 2 =0.99 A. batizocoiCluster IIThese basic studies are designed to assist usin the main objective of the cytogenetics unit,i.e., the utilization of the wild species for theimprovement of groundnuts. The t w o go handin h a n d because m a n y of t h e plants producedin the course of utilization of wild speciesare analyzed in detail, and plants which areanalyzed are then used in crossing programs.The t w o main thrusts of the subprogram are theuse of compatible species to transfer currentlyavailable genes, and the study of the barriers tohybridization and the means of breaking themto make the whole gene pool within Arachisavailable to breeders in the future.B r e e d i n g i n C o m p a t i b l e S p e c i e sThe incorporation of genes from wild speciesinvolves t h e transfer of one or m o r e w i l dspecies genomes to a hybrid where they canu n d e r g o r e c o m b i n a t i o n w i t h A. hypogaeagenomes, and subsequent transfer of the desiredgene or genes into A. hypogaea with theelimination of all undesirable characters fromthe wild species. Five routes have been adoptedto achieve these objectives (Fig. 2).Triploid RouteSmartt and Gregory (1967), Moss and Spielman(1976), Raman (1976), and Moss (1977) have allproduced hexaploids by chromosome doublingin a triploid hybrid. As early as 1976, ICRISATreceived hexaploids from the program at ReadingUniversity. These hexaploids combined thegenomes of A. cardenasii, A. chacoense andArachis species No. 338280 with A. hypogaea,and were screened for leaf spot resistance atICRISAT, which is mainly infested by late leafspot (C. personatum). Resistant plants wereselected from each type of hexaploid, and havebeen backcrossed to different cultivars of A.hypogaea (Moss 1980). These progenies aren o w in the fourth generation of backcrossingand tetraploid and near tetraploid plants arebeing screened for disease resistance. Manyhexaploids were also resistant to rust. There isno correlation between leaf spot or rust resistanceand defoliation in hexaploids derivedfrom resistant wild species, as some hexaploidssusceptible to disease do not defoliate. Conversely,some hexaploids w i t h f e w small lesionssuffer severe defoliation (Moss et al.83

GENOME TRANSFERGENE TRANSFER(1a) 4X Cult.2X Wild(1b) 4 X Cult.2X Wild(2) 2X Wild C h r o m o s o m edoubling(3) 2 x W i l d2X Wild(4) 4X Wild4X Cult.3X C h r o m o s o m edoubling3X4X4X Cult.2X Chromosome.doubling6X5 X - 6 X4X4X4X Cult.4XReciprocalbackcrossingw i t hA. hypogaeaFigure 2. Utilization of diploid and tetraploid wild species.1979). T h e f e r t i l i t y of t h e h e x a p l o i d s andbackcrosses ranges f r o m nil, in some sterile butvegetatively vigorous plants, to highly productive.Some plants produce many pegs per nodeand pegs per plant, but few pods, whilst othershave good reproductive efficiency.Crosses between A. hypogaea and five diploidspecies have produced 92 pods (Table 1).Five triploids have been established f r o m sproutsand the remaining seed will be used toproduce hexaploids.The artificial induction of polyploidy in a triploidto restore fertility, can be difficult and timeconsuming, so the development of a techniquewhereby large numbers of cuttings of the steriletriploid can be treated has increased the productionof hexaploids (Spielman and Moss1976; Nigam et al. 1978). Triploids can producefertile gametes through the formation of a restitutionnucleus and by segregation giving 2nor near 2n gametes. Studies of Anaphase I ofmeiosis show that 30, 20 and hyper-20 c h r o m o -some cells occurred; triploids have producedseed in the field at ICRISAT.This process may be environmental and/orgenotype specific; for instance high temperaturein India may be one of the reasons for theformation of unreduced gametes, and the triploidsdiffer in the frequency w i t h w h i c h theyproduce seed. This latter may be due to thedifferent w i l d species used, or an effect of thedifferent A. hypogaea genotypes w h i c h areknown to affect the amount of pairing in hexaploids(Spielman et al. 1979).A u t o t e t r a p l o i d RouteThe production of an autotetraploid f r o m a diploidw i l d species enables all hybridization andgenome transfer to be done at the tetraploidlevel, and increases the dosage of w i l d speciesgenes. Autotetraploids have been produced inseven taxa (Table 2). Of these only A. batizocoi(4x) has produced seed; many plants of theothers remained sterile and eventually died.However, three autotetraploids were successfullyused as male parents in crosses w i t h A.hypogaea (Table 3). The resultant progenies aremorphologically similar to A. hypogaea, butcytologically unstable, and sterile. A number ofgenerations of selfing of the autotetraploids willincrease the frequency of balanced gametes,and the likelihood of fertile hybrids w i t h A.hypogaea. Hybrids will be backcrossed to A.hypogaea to restore fertility whilst selecting desirablerecombinants.A m p h i p l o i d RouteC h r o m o s o m e d o u b l i n g in a hybrid between t w odiploid w i l d species produces an amphidiploidwhich combines the t w o wild species, which ist h e s a m e ploidy level as tetraploid A. hypogaea,and increases the number of genomes in thehybrid and therefore the number of possiblerecombinants. If the t w o w i l d species used arethe ancestors of A. hypogaea, the amphidiploidwill be a synthetic A. hypogaea, and this may bethe most promising tetraploid derivative of the84

T a b l e 1. Crossability b e t w e e n A. Hypogaea a n d diploid species of s e c t i o n Arac his.CrossNo. ofPollinationsNo./%of pegsN o . / %of podsA. hypogaea x A. correntinaA. hypogaea x A. batizocoiA. hypogaea x A. villosaA. hypogaea x A. duranensisA. hypogaea x A. sp 338280636487584424/3820/3138/4419/3315/3422*/3516/2526/3014*/2414/32Total 316 116/37 92/29* Sprouts produced.T a b l e 2. P r o d u c t i o n of a u t o t e t r a p l o i d s f r o m w i l d diploid Arachis species.SpeciesSeedlingstreatedPlantssurvived2xplants4xplantsA. villosa 17 14 11 4A. correntina 18 16 10 2A. chacoense 5 1A. sp 338280 19 12 3 3A. sp 263133 8 5 4 1A. duranensis 7 6 2 2A. cardenasii 15 14 1 3A. batizocoi 26 21 11 10T a b l e 3. Crossability b e t w e e n A. hypogaea and a u t o t e t r a p l o i d s of section Arachis.CrossNo. ofpollinationsNo./%of pegsNo./%of podsA. hypogaea x A. sp 338280 (4x)A. hypogaea x A. villosa (4x)A. hypogaea x A. sp 263133 (4x)13213911316/1230/2219/1713*/1020*/1417/15Total384 65/17 50/13* Sprouts p r o d u c e d .wild species with regard to the genetic improvementof A. hypogaea. Intracluster crossesare much more successful than interclustercrosses (Fig. 3).Fifty-one amphiploids have been raised from17 different cross combinations of wild species,including A. batizocoi (Table 4), and eight differentcombinations have been successfully crossedw i t h A. hypogaea (Table 5). The resultantprogenies are being analyzed morphologicallyand cytologically; their behavior is similar tothe progenies obtained through the autotetraploidroute. The amphiploids involving threespecies are the most fertile.Use of Tetraploid Wild SpeciesA. monticola has been crossed with A.hypogaea and fully fertile hybrids have beenproduced.85

A. villosaA. correntinaA. chacoenseThis means that there is a good probability ofgene transfer through chromosome pairing inthese hybrids and backcrosses producing newgene combinations in progenies, enablingselection of the desired plants.A. sp 338280A. sp 263133 (LL)A. sp 263133 (SL)A. duranensisA. cardenasii27/16A. batizocoiInduced TranslocationSuch chromosome pairing may not alwaysoccur, either because of the incorporation of anonhomologous genome, or because the geneticbackground of the hybrid prevents pairing ofhomologous genomes. In such cases translocationof chromosome segments has to be inducedthrough mutagenesis.Total no. of pollinationsTotal no. of pegsTotal no. of podsFigure 3.G e n e TransferPercentages of peglpod productionin interspecific crosses in sectionArachis.By Chromosome Pairing53481453901Our cytological analysis of the diploid wildspecies, F1 hybrids and triploids resulting fromcrosses of wild diploid species with Ahypogaea has indicated that there is chromosomehomology or homoeology among thegenomes of all the wild diploid species studiedand between these genomes and A hypogaea.Barriers to Hybridizationand Means of Breaking ThemA hypogaea has not been successfully andrepeatably crossed with any species outsidesection Arachis (Gregory and Gregory 1979).Many species in other sections have potentialas gene sources in groundnut improvement(Moss 1980). Tetraploid wild speciesare found in section Rhizomatosae (Gregoryand Gregory 1979) and these species are ofspecial interest as they are immune to manypathogens. Several attempts have been madeby many people over the years to achieve anintersectional hybrid but these have not beensuccessful (Gregory and Gregory 1979). Recentadvances in the knowledge of the physiologyand development of pollen, factors involved inpollination and advances in the technology ofTable 4.Number of amphiploids established in section Arachis.A correntinaA sp 338280A duranensisA. sp 263133A chacoenseA. chacoense xA. cardenasiiA villosa 6 2A. correntina 4 1 5A sp 338280 2 2A. duranensis 1 1 3 5A. sp 263133 2 3A. batizocoi 2 1 886

Table 5. Crossabllity batween A. hypogaea and amphlploids.CrossNo. ofpollinationsNo./%of pegsNo./%of podsA. hypogaeaX[A. correntinaX[A chacoense x A. cardenasii)]160 26/16 22*/14A. hypogaeaX[A. sp. 338280X(A. chacoense x A. cardenasii)]A. hypogaeaX{A. correntina x A. villosa)A, hypogaeaX{A. villosa x A. sp 338280)A. hypogaeaX(A duranensis x A. chacoense)A. hypogaeaX(A batizocoi x A. villosa)A. hypogaeaX(A batizocoi x A. duranensis)A. hypogaeaX[A. batizocoi x A. chacoense)164 42/26 32*720199 62/31 42*721135 15/11 15*/1196 9/9 7»/729 8/28 7/2418 7/39 5*/2810 7/70 3*/30Total 811 176/22 133/16* Sprouts produced.tissue culture have increased the possibility ofproducing hybrids between species which werepreviously considered to be genetically isolated(Heslop Harrison 1978; Vasil 1978, 1980;Shivanna et al. 1979; Sala et al. 1980).In June 1979 a project was initiated to investigatethe barriers to intersectional hybridization.Fluorescent microscopic comparison of thecompatibly and incompatibly pollinated pistilsshowed that in the former, the pollen tubeswere smooth with small callose patches distributedevenly along the lengths of the pollentubes. In the incompatibly pollinated pistils,however, the callose depositions along thepollen tube were uneven and in larger quantitiesindicating a retarded growth of the tubes.However, a small frequency of incompatiblepollinations induced peg initiation and elongation,though these usually dried and degeneratedbefore they penetrated the soil.87

A number of techniques have been tested fortheir efficiency to overcome such incompatibility.Plant growth hormones applied to the ovarywere found to increase the frequency of pegformation in incompatible crosses. The initialtrials, using cytokinin at 10 -6 M applied to cottonwebs wrapped round the ovaries, were followedby trials using four concentrations ofkinetin and three of benzylamino purine, as wellas auxins and gibberellic acid. The effects ofthese treatments are shown in Table 6. Kinetin,naphthaleneacetic acid and gibberellic acid haveall significantly increased the pegging percentage.Some of these pegs have been left to formpods in the soil. Others have been excised fromthe plants for aseptic culture of the tip of thepeg, or the ovule, or the embryo. We have so farbeen able to culture immature embryos successfullyinto seedlings using Murashige andSkookg's 1962 medium. Our attempts to culturepegs according to Ziv and Zamsky (1975), orovules according to Martin (1970), even fromcompatible crosses, have not given satisfactoryrepeatable results. We were able to inducenormal embryogeny in one ovule culture up tothe cotyledonary stage of the embryo by usingan aqueous peg extract in the medium.While excising the embryos from seed forculture, the cotyledons were also cultured. Weobserved that the end of the cotyledon proximalto the embryo is a highly embryogenic tissuewhich gives rise to roots, shoots, embryoids orwhole plants depending upon the hormonalbalance in the medium. We have also beentrying to regenerate plants from leaflet segmentsand have been able to induce roots butnot shoots or embryos, although we have triedfour different basic media, White (1943),Murashige and Skoog (1962), Gamborg et al.(1972) and Kao and Mickayluk (1975), with arange of auxins and kinetins, as well as supplementingwith coconut milk, casein hydrolysate,yeast extract, malt extract or gibberellic acid.ConclusionConsiderable progress has been made with aTable 6.Effact of soma plant growth hormones on pegging after pollination of tetraploid speciesof section Anchls with Arachis sp PI No. 276233 of section Rhizomatotae.Arachis monticola A. hypogaea var . Robut33-1No. of Pegs formed No. of Pegs formedCross Treatment pollinations (%) pollinations (%)Compatible None 201 34.33 156 34.62(self)Incompatible None 314 17.20 147 15.65(control)Incompatible Kinetin, 10 -4 M 21 14.29" Kinetin, 10 -5 M 90 15.56 82 25.00" Kinetin, 10 -6 M 75 18.67 55 25.46ItKinetin, 10 -7 M 95 14.75 87 40.23" Benzyl Adenine, 10- 5 M 134 22.39" Benzyl Adenine, 10- 6 M 191 20.42"Benzyl Adenine, 10- 7 M 98 19.39"Indole Acetic Acid 107 13.08 53 24.53" (25 ppm)» Napthalene Acetic Acid"(25 ppm)2, 4-Dlchloro PhenoxyacetlcAcid (25 ppm)* Gibberellic Acid(25 ppm)"Kinetin 70- 4 M +Indole Acetic Acid (25 ppm)129 17.83 52 42.3173 17.81 18 22.2237 48.6589 24.7288

number of different ways of utilizing wild species.The number of plants produced, and the rangeof variation they show, indicate that there isgood potential for transferring desirable charactersf r o m wild species. Although the wildspecies were originally considered solely assources of disease resistance, the progeniesfrom interspecific crosses have potential as ameans of expanding the gene pool of Arachiswith respect to a number of other desirablecharacters.Results of attempts to break the barriers tohybridization hold promise for utilization ofcharacters f r o m species outside sectionArachis.ReferencesABDOU, Y. A. M. 1966. Ph.D. Thesis, North CarolinaState Univ., Raleigh, USA.ABDOU, Y. A. M., GREGORY, W. C, and COOPER, W. C.1974. Sources and nature of resistance to Cercosporaarachidicola Hori and Cercosporidium personatum(Beck and Curtis) Deighton in Arachisspecies. Peanut Science 1: 6 - 1 1 .BUNTING, A. H., GREGORY, W. C, MAUBOUSSIN, J. C,and RYAN, J. G. 1974. A proposal for research ongroundnuts {Arachis) by ICRISAT. ICRISAT Mimeo.ICRISAT, Patancheru, A. P. 502 324, India.GAMBORG, O. L, MILLER, R. A., and OJIMA, K. 1968.Nutrient requirements of suspension cultures ofsoybean root cells. Experimental Cell Research50: 151-158.GREGORY, M. P., and GREGORY, W. C. 1979. Exoticgermplasm of Arachis L. Interspecific hybrids. Journalof Heredity 70: 185-193.HESLOP-H ARRISON, J. 1978. Genetics and physiology ofangiosperm incompatibility systems. Pages 73-92in Proceedings of the Royal Society, London. 202 B.MARTIN, J. P. 1970. Culture in vitro d'ovules Arachide.Oleagineux 253: 55-56.Moss, J. P. 1977. Cercospora resistance of interspecificArachis hybrids. Proceedings of theAmerican Peanut Research and Education Association9: 34 (Abs.).Moss, J. P. 1980. Wild species in the improvement ofgroundnuts. Pages 525-535 in Advances in legumescience (eds. Summerfield and Bunting),Vol. 1, Proceedingsof the International Legume Conference,Kew, England, 1978.Moss, J. P., and SPIELMAN, I. V. 1976. Interspecifichybridization in Arachis. Proceedings of the AmericanPeanut Research and Education Association8: 88 (Abs.).Moss, J. P., SINGH, A. K., BURGE, A. P., and BRADLEY, S.1979. Wild species in the improvement ofgroundnuts. 1, Disease reaction of hexaploids. Proceedingsof the American Peanut Research andEducation Association 11: 55 (Abs.).MURASHIGE, T., and SKOOG., F. 1962. A revisedmedium for rapid growth and bioassays with tobaccotissue cultures. Physiologic Plantarum15: 473-497.NIGAM, S. N., Moss, J. P., and GIBBONS, R. W. 1978.Vegetative propagation oi Arachis species. ICRISATMimeo. ICRISAT, Patancheru, A. P. 502 324, India.RAMAN, V. S. 1976. Cytogenetics and breeding inArachis. Today and Tomorrow's Printers and Publishers,New Delhi, India.RAO, K. N., and MICHAYLUK, M. R. 1975. Nutritionalrequirement for growth of Vicia hajastana cells andprotoplasts at a very low population density in aliquid media. Planta 126: 105-110.SALA, F., PARIS, B.,CELLA, R., and CIFERRI, 0.1980. Plantcell culture: results and perspectives. Elsevier-North Holland Biomedical Press, Holland.SHARIEF, Y. 1972. Ph.D. Thesis, North Carolina StateUniv., Raleigh, U.S.A.SHIVANNA, K. R., JOHRI, B. M., and SASTRI, D. C. 1979.Development and physiology of ang iosperm pollen.Today and Tomorrow's Printers and Publishers.New Delhi, India.SIMPSON, C. E. 1976. Peanut breeding to exploit sourceof variability from wild Arachis species. Proceedingsof the American Peanut Research and EducationAssociation 8: 87 (Abs.).SINGH, A. K., Moss, J. P., and SASTRI, D. C. 1980. Utilizationof wild relatives in genetic improvement ofArachis hypogaea: Techniques. Proceedings AllIndia Seminar on Current Methodological Approachesin Cytogenetics, Centre of Special Assistancein Cytogenetics, Patna University, India.SMARTT, J., and GREGORY, W. C. 1967. Interspecificcross-compatibility between the cultivated peanutArachis hypogaea L. and other members of genusArachis. Oleagineux 22: 455-459.89

SMARTT, J . , G R E G O R Y , W . C , and GREGORY,M.P. 1978a.The genomes of Arachis hypogaea L. 1. Cytogeneticstudies of putative genome donors. Euphytica27: 665-675.S MAUTT, J., G REGORY, W. C, and G REGORY, M. P. 1978b.The genomes of Arachis hypogaea. 2. The implicationsin interspecific breeding. Euphytica 27: 667-680.SPIELMAN, I. V., and Moss, J. P. 1976. Techniques forchromosome doubling in interspecific hybrids inArachis. Oleagineux 31: 491-494.SPIELMAN, I. V., BURGE, A. P., and Moss, J. P. 1979.Chromosome loss and meiotic behaviour in interspecifichybrids in the genus Arachis L. and theirimplications in breeding for disease resistance.Zeitschrift fur Pflanzenzuchtung 83: 236-250.STALKER, H. T., 1980. Cytogenetic investigations in thegenus Arachis. Proceedings this workshop.VASIL, I. K. (ed.). 1980. Perspectives in plant cell andtissue cultures. International review of cytology,Supplement 11, Parts A and B. Academic Press, NewYork, USA.VASIL, I. K., AHUJA, M. R., and VASIL, V. 1979. Planttissue cultures in genetics and plant breeding. Advancesin Genetics 47: 127-216.WHITE, P. R. 1943. A handbook of plant tissue culture.J. Catell Press, Lancaster.Ziv, M., and ZAMSKI, E. 1975. Geotropic responses andpod development in gynophore explants of peanutArachis hypogaea cultured in vitro. Annals ofBotany 39: 579-583.90

Session 4 — Cytogenetics and Utilization of WildSpeciesDiscussionC. Raja ReddyThe cytology and pollen fertility of the hybridbetween A. villosa xA correntina point totheir close similarity, which is also substantiatedby the D 2 analysis. In view of this, is theseparation of the two species into distinctones justified?H. T. StalkerThe two species are recognized in taxonomybased on the differences in external morphology.In fact, most species of Arachis aredelineated from considerations of morphologicaldifferences. A biosystematic classificationof the species of Arachis is no doubt desirable,but this has to wait till an extensive study oftheir cytogenetics is carried out.K. S. LabanaHave any monosomicornullisomic lines beendeveloped in Arachis?H. T. StalkerStudies on monosomic and nullisomic plantsin Arachis have been meager. The limitedinvestigations have shown their cytologicalinstability. The development of such lines inArachis will entail intensification of researchon this aspect.P. S. ReddyMany methods of interspecific gene transferencefrom the wild species of Arachis to thecultivated A. hypogaea are cited but not oneon development of haploid plants of A.hypogaea through pollen culture and utilizingsuch plants in hybridization with diploidspecies. Does this not appear to be a profitableapproach?J. P. MossThe information on induction of haploidy in A.hypogaea through pollen culture gained fromstudies carried on in this country andelsewhere are awaited.U. R. MurtyAttempts at culturing the pollen of triploidhybrids between A. hypogaea and diploidspecies are likely to lead to the realization ofaneuploids.A. K. SinghAlthough this route may not be very fruitful ontheoretical considerations, it is worth a trial.R. W. GibbonsHexaploids generally suffer from low podyields. Has there been any attempt to study theprogeny behavior of the hexaploids from thisangle?H. T. StalkerThe hexaploids have been found to be lowyielders. But exception to this generalizationhas also been noticed. In the case of theprogenies developed from the hexaploid of Ahypogaea x A cardenasii, plants in the 9thgeneration showed an improvement in podyields comparable to that of cv NC-5.R. 0. HammonsWould it be feasible to pursue cytogeneticresearch through the use of haploid plantsisolated from twin seedlings?H. T. StalkerTwin seedlings from seeds of A hypogaea areknown to occur at a low frequency and thesewere found to be tetraploid in constitution.Efforts are under way to locate haploid seedlingsfrom haploid-diploid twins.J. P. MossExperience has shown that small andshriveled seeds have given aneuploids ratherthan haploids. The significance and importanceof haploids in cytogenetic analysis is91

well-realized, and exercises to isolate haploidsare under way.What is the basis of differentiation of thegenomes as A1, A2, and A3?H. T. StalkerThe differentiation is based on the karyomorphologyof the species, nature of chromosomepairing in hybrids, and their levels of fertility.Such a genomic differentiation is only tentativeand more evidence has to be gathered toconfirm it.C. Raja ReddyThe karyological features of nine diploidspecies have been taken into consideration forthe D 2 analysis. A larger array of materialshould have been included in this analysis.A. K. SinghThe necessity to draw more species of D 2analysis is recognized, and as and when additionsare made, the analysis will be continuedbut not on a priority basis.H. T. StalkerIn view of the importance attached tocytogenetic investigations of applied value,studies on D 2 analysis may be left to bepursued by academic institutions rather thanby ICRISAT.V. S. RamanLet me give my understanding of this D 2analysis that has been done with reference tonine diploid species. In group 1, eight speciesare accommodated and in group 2, Abatizocoi stands out prominently. With referenceto the origin of A hypogaea as currentlyunderstood, A batizocoi is one of the parentsinvolved in the origin. So this analysis justifiesthe stand taken in the hypothesis that Abatizocoi is one of thediploid parents involvedin the origin of the tetraploid. Even with thisanalysis, the piece of fundamental informationcan be drawn.92

Session 5Crop Nutrition and AgronomyChairman: A. NarayananRapporteurs: P. W. AminR. W. GibbonsV. K. Mohan

Increasing Nitrogen Fixation of the Groundnutby Strain and Host SelectionJ. C. Wynne, G. H. Elkan and T.J. Schneoweis*As the cost of nitrogen fertilizer derived fromfossilfuelscontinuestorise, biological nitrogenfixation will become more important for thecontinued productivity of agricultural crops. Inthe immediate future, successful increases inbiological nitrogen fixation most likely willcome from improvements in the symbioticfixation by legumes.Groundnuts (Arachis hypogaea L), sincethey are grown on about 18 million hectares in82 countries, should contribute to the increasein dinitrogen fixed. Increases in dinitrogen fixedby groundnuts can be accomplished by theselection of more effective strains of Rhizobiumand/or selection of more efficient host plants.Selection of EffectiveStrains of RhizobiumGroundnuts are a member of the cowpeacross-inoculation group. Rhizobia isolated froma diverse group of legumes are capable ofnodulating groundnuts (Burrill and Hansen1917; Walker 1928; Carroll 1934; Raju 1936;Mostafa and Mohmoud 1951; Berenyi 1962;Rajagopalan and Sadasivan 1964; Doku 1969;Gaur et al. 1974a). Not all rhizobial strains areequally effective in fixing nitrogen in symbiosiswith groundnuts (Allen and Allen 1940; Collins1943; Erdman 1943; Berenyi 1962; Denarie1968; Vidyasekaran et al. 1973; Dadarwal et al.* Associate Professor of Crop Science, Professor andResearch Assistant of Microbiology, respectively,North Carolina State University, Raleigh, NorthCarolina, 27650, USA.Note: Paper No. 6638 of the Journal Series of theNorth Carolina Agricultural Research Service.This research was partially supported bygrants USDA-SEA-CR 701-15-24 and 616-15-192 under A.I.D. PASA AG/TAB 610-9-76.1974; Weaver 1974). Therefore, effective rhizobialstrains should be identified and used toinoculate groundnuts to ensure an effectivesymbiosis (Erdman 1943; Schiffmann 1961;Schiffmann and Lobel 1970; Gaur et al. 1974a;Lopes et al. 1974; Weaver 1974; Burton 1976).However, to be useful, effective strains mustsurvive in and colonize the soil into which theyare introduced. Unfortunately many effectivestrains have been unable to survive andcolonize under field conditions (Schiffmann1961; Shimshi etal. 1967; Schiffmann and Alper1968b; Pant and Iswaran 1970; Gaur et al.1974b; Iswaran and Sen 1974; Kumara Rao etal.1974). Introduced strains which survive mustalso be able to compete for infection sites on theroot with less effective native strains. Frequentlyintroduced strains are not very competitive(Berenyi 1962; Denarie 1968).Significant responses to inoculation with effectivestrains have largely been restricted tocontrolled conditions (Chomchalow 1971) andfield experiments on virgin groundnut soils(Duggar 1935b; Collins 1943; Schiffmann1961; Berenyi 1962; Shimshi et al. 1967;Schiffmann and Alper 1968a,b; Denarie 1968;Burton 1976). When inoculation with effectivestrains has been successful, the result has beenincreased yields of fruit, plant dry matter, nodulation,percentages of large fruits and seeds,and nitrogen content of foliage and seed.The collection, identification, and use ofsuperior strains of rhizobia should be anintegral part of a groundnut research program.Inoculants produced from superior strains specificallytailored to the local environment shouldbe used where nodulation is not adequate forgood growth and high yields. These inoculantsshould also be used where nodulation appearsadequate but a growth response to nitrogenfertilizer is observed si nee this suggests that thestrains producing the nodules may not be efficient.95

Nodule Collection, StrainIsolation, and MaintenanceStrains of Rhizobium for groundnuts are maintainedat several international and nationalcenters such as ICRISAT; USDA, Beltsville,Maryland, USA; and NifTAL, University ofHawaii, USA. Because of the limited research onthe groundnut-Rhizobium symbiosis, only afew of the available strains have been testedwith groundnuts. For example, the USDARhizobium culture collection catalog (1979)lists 16 strains for groundnuts of which onlyfour are recommended for symbiotic effectiveness.The NifTAL catalog (1978) recommendsfive strains and lists 11 additional strainsthat are effective with groundnuts.Because of the limited number of recommendedstrains of Rhizobium and the lack ofknowledge about their performance in symbiosiswith the groundnut germplasm growth inNorth Carolina, we concluded that one of theprincipal goals of our program should be toisolate and identify effective rhizobial strains.Initially we obtained strains of rhizobia fromother researchers. Additional strains ofRhizobium were isolated from nodules collectedfrom centers of diversity for the genusArachis in South America. The nodules wereobtained from Arachis collecting expeditionssponsored by IBPGR and led by W. C. Gregory(North Carolina State University, Raleigh) andC. E. Simpson (Texas A & M University,Stephenville). After sampling, the nodules wereplaced in 7.5 ml plastic vials containing anhydrouscalcium chloride, covered with a cottonplug, and mailed to our laboratory in NorthCarolina. After the nodules were received fromSouth America, they were rehydrated in sterilewater for 4 hours at 5 o C. They were thenaseptically dissected, and a nichrome wire wasused to streak some of the tissue on yeastextract mannitol agar in previously poured petriplates. Cultures were incubated at 28°C andexamined daily for raised mucoid colonies typicalof rhizobia. These colonies were restreakeduntil pure cultures were obtained. Using thesetechniques, 234 bacterial isolates representing78 germplasm collections were obtained fromnodules collected in 1976-77 (Tables 1,2). Additionalstrains are now being isolated fromnodules collected in 1979 and the spring of1980.The Rhizobium culture collection is maintainedin screw-capped tubes containing yeastmannitol agar and stored at 5°C. These culturesare maintained in duplicate with one.set beingthe working collection. In addition to agarslants, the mother collection is also preservedon porcelain beads with silica gel and inlyophilized form. These latter two techniqueslimit loss of culture viability with minimal risk ofmutation or contamination. Transfers of thisRhizobium collection are provided upon requestto interested investigators. Additionalcowpea strains from the diverse environmentwhere groundnuts are grown need to be collected.Evaluation of Effectivenessof StrainsWe use siratro (Macroptilium atropurpureum)for preliminary screening of isolates. This smallseededlegume is grown in the growth chamberin 30 ml serum bottles capped with plastic bags.The roots are examined for nodulation after 21days. Strains capable of nodulating siratro areincreased for testing with groundnuts. Thisfurther evaluation of these rhizobia is usuallycompleted in stages. We first test rhizobia in thegreenhouse with two host genotypes of differentorigin. Those strains that are effective ingreenhouse studies must then be tested in thefield in competition with indigenous rhizobia.Greenhouse EvaluationArgentine (Spanish type) and NC-4 (Virginiatype), two cultivars representing the two subspeciesof groundnuts, are used as host plants(Wynne et al. 1980). Plants are grown in modifiedLeonard jars similar to those proposed byWacekand Aim (1978). The jars and a 2:1 sand:vermiculite medium are autoclaved before useto prevent contamination.Seeds of each genotype are surface-sterilizedby soaking in calcium hypochlorite solution (10gin 150 ml water) for 10 min followed by rinsingwith sterile water five times. The groundnutsare then pregerminated in sterilized vermiculiteand placed 25 mm into the medium in the jars.Before covering the seed, a 1 ml suspension ofthe proper rhizobial strain (approximately 10 9cells/ml) is added aseptically to the seed for alltreatments except for an uninoculated controlwhere sterile culture medium alone was added96

Table 2.Origin of Rhlzoblum isolates collected from South American groundnuts.Coll. No. Isolated from Area collected Soil description Date collected77 Colorado Chico del Palmai' Cototo, 10 km E of Villa 11 Apr 1977(red seeds)Montes92 Overo Colorado Blanco Saavedra, Sta. Cruz Dark black loam 19 Apr 1977(grande)138 Overo Puento de Mataral, Sta. Cruz 25 Apr 1977146 Overo Valle Abajo, Mairana 28 Apr 1977150 Palido Teneria — Aiquile, dept. Brown sandy loam29 Apr 1977Cochabamba151 Sara Mani Mesa Rancho —Aiquile Medium heavy, dark brown 29 Apr 1977to the seeds. Anitrogen control (10 ml of a 1 mgN/ml solution of N H 4 N O 3 applied three timesduring the test) is also included. The seed andinoculum are then covered with sand. The jarsare watered through the glass tube into thebottom storage area. The distilled water movesthrough a 6 mm thick nylon wick up into themedia in the upper jar. Treatments are replicatedfive times with plots arranged in a randomizedblock design in the greenhouse. Nutrientsolution (150 ml) is added twice during thegrowing period. The nutrient solution consistedof Bond's Stock salt mixture supplemented withzinc, molybdenum and cobalt micronutrients.After 50 days of growth, the plants are harvested.Plant color is rated on a scale of 1 -3 with1=green and 3=yellow. Nitrogenase activityis measured for the root system of each plantusing acetylene reduction methodology.Nodules are counted and removed so thatnodule mass can be determined. The root andplant tops are dried, weighed, and the tops areground for determination of nitrogen using theKjeldahl technique.We have evaluated several strains ofRhizobium in the greenhouse for their ability tofix nitrogen. Rhizobial strains have been foundto significantly influence plant color, plant dryweight, nodule number, nodule mass, percentnitrogen, total nitrogen, and nitrogenase activity(Table 3). Strains often perform differentiallyon the two host genotypes giving a significanthost x strain interaction for traits indicative oftheir nitrogen fixing ability. This strain-hostspecificity suggests that rhizobial strains mustbe screened in symbiosis with diverse hosts orwith the host genotype with which they aregoing to be used.Total nitrogen accumulated is the best measureof the efficiency of a rhizobial strain.However, both plant color and plant dry weightare significantly correlated with total nitrogensuggesting that the measurement of these twotraits is sufficient in evaluating strain efficiencyin greenhouse studies (Table4). Thesetraits canbe utilized by researchers with limited resourcesto screen rhizobia for effectiveness in symbiosiswith local groundnut genotypes.From the more than 100 unique isolates thatwe have evaluated in the greenhouse, we haveidentified several strains that fix more nitrogenthan the commercial strains used as checks.Although additional testing is needed, thesestrains are now available to other rhizobiologistsinterested in cowpea rhizobia.Field Evaluation of RhizobiaAfter greenhouse evaluation, we test the nitrogenfixing ability of rhizobial strains in the fieldin the presence of endemic rhizobia (Elkan et al.1980). In a preliminary study we evaluatedstrains previously tested in the greenhouse fortheir nitrogen fixing ability in thefield in ordertocompare field and greenhousetest results. Ninestrains of Rhizobium in symbiosis with 48genotypes were tested in a field previouslyplanted to groundnuts.The rhizobial strains applied in a water suspensionsignificantly influenced nodulation (0.05level of probability) and nitrogen fixed as measuredby nitrogenase activity (0.01 level). Whenaveraged over the 48 host genotypes, thegreatest nodulation was produced by strain176A34 (Table 5). Strains 176A22 and 3G4b4also produced significantly more nodules than98

Table 4. Correlation coeffleiants for nitrogan-flxlng traits in two graanhouso studies.Plant Nodule Nodule Percent NitrogenaseTrait Study weight number mass nitrogen Total N2 activityPlant color* 1 - . 9 3 * * - . 8 4 * * -.75* - . 9 5 * * - . 9 5 * * - . 8 9 * *2 - . 9 3 * * -.44 -.54 - . 9 4 * * - . 9 7 * * - . 7 8 * *Plant weight (g) 1 — .79** .54 .83** .99** .83**2 — .45 .61 .90** .97** .73*Nodule number 1 .89** .83** .82** .75*2 — — .92** .33 .39 .47Nodule mass (g) 1 .89** .67* .68*2 — — — .49 .54 .68*% Nitrogen of plant 1 — — — . 8 1 * * .57*2 — — — — .97** .86**Total N2 of plant (g) 1 — — — — .86**2 — — — — — .78**Traita. Rating 1 = green and 3 - yellow.* ** Indicates simple correlation coefficients significant at 0.05 and 0.01 levels of probability.Tabla 5. Maan nodulation rating and nltroganaaaactivity for strains ofRhiz oblum and an uninoculated controlfor fiald grown groundnuts.Nodulation NitrogenaseStrain rating* activity b3G4b20 2.81 39.1176A34 3.10 38.7176A22 3.07 35.13G4b5 3.06 35.83G4b4 3.07 31.03G4b21 2.98 32.842B2 3.06 33.832H1 2.93 35.732Z3 3.04 31.0Control 2.89 32.5LSD (0.05) 0.17 3.0a. Rated 156 days after planting with 1 = little and 5 - heavynodulation.b. C2H4/plant per hr. Mean over 48 genotypessampled91, 95,100, 119 and 127 days after planting.the inoculated controls which were inoculatedwith the naturally occurring strains. Thegreatest nitrogenase activity, however, occurredwith strain 3G4b20. Strains 176A34, 3G4b5and 32H1 also had significantly higher nitrogenaseactivity than the naturally occurringstrains. Conversely, strains 3G4b4 and 3273 hadslightly but insignificantly lower nitrogenaseactivity than the endemic strains.The nitrogenase activity for the rhizobial strainswhen applied to Florigiant, a Virginiacultivar that is grown on most of the acreage inNorth Carolina, was determined for five samplingdates (Table 6). All plots of Florigiant includingthe uninoculated control were heavily nodulated.Six of the nine strains, however, hadslightly higher mean nitrogenase activity thanthe naturally occurring strains (control),although only strain 3G4b21 was significantlybetter than the control. These data indicate thatsome strains are able to compete for infectionsites and are more effective than naturallyoccurring strains. Strain 42B2 successfullycompeted for infection sites but produced lesseffective nodules than the naturally occurringstrains. This strain was also ineffective ingreenhouse evaluations.Nitrogenase activity measured in thegreenhouse forthese same strains in symbiosiswith a Spanish and Virginia cultivar was correlated(r = 0.73*) with mean nitrogenase activity100

Table 6. Nltroganaaa activity C 2 H 4 /hrpar plant) for strains of Rhlzoblumand an unlnoculated control forpeanuts of cv Florlgiant for five samplingdatas.Days after plantingStrain 91 95 100 119 127 Mean3G4b20 49 70 64 69 28 56176A34 45 50 61 49 20 45176A22 52 60 68 65 30 553G4b5 49 52 74 61 32 543G4b4 58 50 73 48 30 523G4b21 55 71 69 74 33 6042B2 44 47 45 49 18 4132H1 38 50 71 66 39 5332Z3 37 56 56 62 26 47Control 48 51 54 64 26 49Mean 47.4 55.6 63.6 60.6 28.3 51.1LSD (0.05) Sa mpling date 8LSD (0.05) Strain 12in the field. This indicates that screening ofrhizobial strains in the greenhouse is effectiveas a preliminary predictor of rhizobial strainperformance in the field.A similar field study conducted during 1979involved 10 rhizobial strains and two groundnutcultivars, Florigiant and Spantex, (Spanishtype). The strains significantly influenced nodulation,nitrogenase activity and plant weight butnot yield of fruit (Table 7). A significant (0.05level) genotype x strain interaction was foundfor plant weight, indicating that rhizobial strainswere not equally effective for the twogroundnut cultivars (Table 8). These resultsstrongly suggest that the host genotype mustbe considered in rhizobial strain selection.These field data are not very dramatic butthey are very encouraging. Considering that soilfertility and endemic rhizobial populations arehigh enough to produce high yields, resultsunder these test conditions can be translatedinto spectacular yield increases on nitrogendeficient soils with ineffective or low rhizobialpopulations.Identification of CowpeaMiscellany SubgroupsThe identification of effective strains of rhizobiathrough plant tests in the field and greenhouseis slow and tedious. It would be advantageous ifit were possible to identify a subgroup of thecowpea rhizobia whose primary host cuitivar isTable 7.Strain and control means for yleld and nitrogen-fIxlng traits for field-grown groundnuts.Nodule 8NitrogenaseShootYield perNumber Dry wtactivityweightplantStrain treatment (mg) C 2 H 4 /plant per hr) (g) (g)Control(endemic strain) 396abc 475bcd 1.67abc 54.1abc 718aNitrogen control 276c 370d 1.17c 59.7abc 646a32H1 427abc 442bcd 1.51abc 62.5ab 726aCB 756 334bc 378cd 1.87a 56.3abc 562a3G4b5 485abc 503a-d 1.70abc 53.9abc 562a3G4b21 593a 727a 1.88a 70.2a 695aNC 146.1 642a 625abe 1.44abc 54.0abc 541aNC 92 584a 642ab 1.78ab 53.6abc 634aNC 7.1 553ab 465bcd 1.28bc 51.9bc 654aNC 3.1 458abc 488a-d 1.65abc 53.1be 597aNC 71 437abc 322d 1.62abc 44.5c 542aNC 56 396abc 501a-d 1.94a 61.4ab 650a176A22 545ab 538a-d 1.64abc 55.7abc 595aNC 120 500abc 494a-d 1.67abc 67.6ab 686aa. Nodule number, welghtand shoot weight are means for plants sampled 59 and 166 days after planting. Nltrogenase activity,59 days after planting, and fruit weight, 166 days after planting, are means for single sampling date.Means with different letters are significantly different at 5% level according to Duncan's m ultlple range test.101

Table 8. Ranking of strains of Rhixobium asthay affact plant waight for aSpanish and Virginia groundnut cultivar.Rank Florigiant Spantex1 32H1 NC 1202 CB 756 3G4b213 NC 146.1 NC 564 NC 3.1 32H15 NC 7.1 176A226 3G4b21 CB7567 3G4b5 NC 146.18 NC 120 3G4b59 NC 92 NC 3.110 NC 56 NC 7111 176A22 NC 9212 NC 71 NC 7.1the groundnut or a specific cultivar-group ofgroundnuts.We have adapted for use with Rhizobium sptwo DNA-DNA hybridization techniques whichallow us to rapidly determine the genetic relationshipof isolates within this group of rhizobia.Isolates from individual legume cultivars nodulatedwith cowpea miscellany rhizobia are beingcompared using these hybridization techniquesto determine if there is (or are) any subgroup/sof cowpea rhizobia favoring groundnuts. Conversely,if this host-isolate interaction is determinedto be truly wide spectrum, we hope todetermine if the more ineffective and effectiveisolates can be genetically grouped. This studyis in the preliminary stages. The genetic diversityof this group of bacteria is apparent fromthe DNA-DNA hybridizations. Early evidencepoints to the possibility that bacteria moreefficient in nitrogen fixation with groundnutsare identifiable. If the presence of subgroups (orsubspecies) is confirmed, then it would berelatively easy to identify subgroups of thecowpea miscellany, thus reducing the need forplant tests. This work is continuing and is beingexpanded in our laboratory.Selection of EfficientHost PlantsA second approach to increasing nitrogen fixedby groundnuts, which is applicable regardlessof whether plants are well nodulated by nativerhizobia or whether inoculation is required foradequate nodulation, is to develop hostgenotypes that are more efficient in fixingnitrogen. Although symbiotic nitrogen fixationhas been studied for almost a century, littleeffort has been given to increasing nitrogenfixation in legumes through breeding. Enhancingthe nitrogen fixing process in a leguminouscrop through breeding requires (1) ample geneticvariability, (2) an understanding of the geneticcontrol of the process, (3) a technique formeasuring the desired trait indicative of nitrogenfixation, and (4) a breeding strategy toefficiently utilize the variation.Genotypic Variationin Nitrogen Fixing TraitsDifferences in nodulation for groundnutgenotypes in the field were first reported byDuggar (1935a). Duggar (1935c) found that arunner (ssp hypogaea) genotype developedlarger and more nodules than a Spanish (sspfastigiata) genotype. Inoculation with a singlestrain of Rhizobium increased nodulation of theSpanish line but not of the runner. Albrecht(1943) observed significant increases in fruityield of a Spanish line when inoculated withthree single strains of Rhizobium and a commercialinoculum, while a runner type did notrespond to any of the treatments.Burton (1976) found differences in nitrogenaccumulation among peanut cultivars grown inthe greenhouse with fixation being the onlynitrogen source. Inoculated with single strainsof Rhizobium isolated from plants of four genera,cv Florunner, a Virginia type, was consistentlyhigher in nitrogen content than theSpanish cultivars, Comet, Starr and Spantex.We have found host plant differences innodulation and nitrogen fixing activity in bothgreenhouse and field studies (Wynne et al.1978). Genotypic differences in nodulation bythe native rhizobia found in North Carolinagroundnut fields have also been observed. Thenodulation for 48 genotypes shown in Table 9 istypical of the response observed in NorthCarolina. Virginia types such as cvs Florigiant,Va-72R, NC-5 and NC-6 are more heavilynodulated than Spanish or Valencia types suchas cvs Spanhoma, Spantex, Starr, Argentine,Tennessee Red or New Mexico Valencia.102

Table 9. Ganotyplc maans for nodulation in North Carolina flald study during 1977 at tha UpparCoastal Plain Research Station. aModulationNodulationGenotypes X Genotypes X1. Starr 1.45 25. PI 221068 4.452. Tamnut 74 2.25 26. PI 241633 2.453. Georgia 255 2.60 27. PI 158850 3.004. G-169 2.45 28. PI 158852 3.255. EM 12 1.65 29. Spanhoma 2.256. Florunner 2.75 30. Spantex 2.407. Florigiant 4.90 31. Dixie Spanish 2.858. Va 72R 4.85 32. Starr 2.209. Early Bunch 4.30 33. Argentine 2.1010. UF 714021 3.90 34. Schwarz 21 2.0511. NC 6 3.75 35. Chico 2.0512. Tifrun 3.65 36. PI 337396 3.1013. A 69 4.10 37. PI 261954 2.8514. UF 75102 3.00 38. PI 261955 3.0015. Va 70-64 4.50 39. Tennessee Red 2.8016. NC 5 4.35 40. N. M. Valencia 3.1517. NC 2 3.45 41. PI 275743 2.2018. NC-FIa 14 3.35 42. PI 275744 3.0519. NC 4 3.90 43. PI 275078 2.5020. PI 268837 3.00 44. Greg. #182 1.3021. PI 313946 3.50 45. Greg. #190 1.1522. PI 313947 3.80 46. 71 SAN 290 2.1023. PI 313950 4.45 47. 71 SAN 291 1.9024. A. monticola 2.80 48. NC 3033 3.25a. Nodulation rated 156 days after planting with 1 = little and 5 - high.Nodulation for the genotypes listed in Table 9was measured at a single harvest date nearmaturity. We have found estimates of nitrogenfixing traits at a single harvest may not bereliable as an indicator of the relative performanceof a genotype. For example, when eightcultivars were sampled four times during thegrowing season for their nitrogen fixing ability,both cultivars and harvest dates significantlyinfluenced nodulation and nitrogenase activity(Table 10). The dateXcultivar interaction wasalso significant for all three traits. The twogenotypes from the ssp fastigiata, TennesseeRed and Spanhoma, had lower mean nodulenumber, nodule weight, and nitrogenase activitywhen averaged over all harvest dates.Florigiant, the predominant cultivar in NorthCarolina, had the highest mean nodule number,nodule weight, and nitrogenase activity whenaveraged over all sampling dates. However, thessp fastigiata cultivars were not lowest at allsampling dates nor was Florigiant highest for allsampling dates. These and other unpublisheddata suggest that selection of a genotype basedon a single evaluation of nitrogen fixing abilityduring the growing season may not alwaysidentify the superior genotype.The seasonal pattern of nodulation andN2(C2H2) fixed was similar in this and other fieldstudies. The pattern is better illustrated frombimonthly sampling dates for the cultivarsFlorigiant and Argentine (Figs. 1 and 2).Nodulation increased during the growing seasonuntil a peak was reached 84 days afterplanting for Argentine and 98 days after plantingfor Florigiant. Plants of Florigiant averaged1470 nodules compared to 908 for Argentine atthe time of maximum nodulation. Nitrogenfixation increased during the growing seasonuntil a peak was reached 84 days after103

Table 10.Maana for datas by cultivara for nitroganaaa activity and noduiation (Lawiaton, NorthCarolina, 1978).Sampling date (days after emergence)Cultivar 28 56 84 117Nitrogenase activity (µ moles C2H4/plant per hr)Tennessee Red 4.21 15.59 24.66 17.01Spanhoma 3.35 13.79 21.69 13.44Florunner 3.86 23.04 37.33 24.69B1 1.77 6.04 28.87 27.62Florigiant 5.51 18.83 35.12 34.57NC 4 1.76 15.59 41.55 26.66NC 6 3.93 20.13 33.99 34.18Early Bunch 4.68 17.64 29.56 24.51Nodulation (nodules/plant)Tennessee Red 200.6 666.0 923.1 857.6Spanhoma 162.1 492.4 613.0 494.0Florunner 213.9 771.9 1380.3 1051.8B1 151.5 460.9 1315.9 950.1Florigiant 178.3 771.3 1440.3 1445.1NC 4 202.9 600.7 1273.9 1659.0NC 6 187.2 948.5 1265.8 1302.5Early Bunch 254.0909.51320.4 1266.7Nodul e weight (g/plant)Tennessee Red 0.20 0.75 1.09 1.13Spanhoma 0.26 0.60 0.90 0.80Florunner 0.23 1.26 2.37 1.45B1 0.27 0.57 1.55 1.44Florigiant 0.21 1.11 2.90 2.77NC 4 0.41 0.87 2.10 2.50NC 6 0.46 1.28 2.34 1.78Early Bunch 0.45 1.21 1.47 1.37planting. Nitrogen fixed decreased after thisdate. Maximum N2(C2H2) values exceeded70 umol C2H2/plant per hr for Florigiant comparedto less than 50 for Argentine. Unfortunately,total nitrogen analyses have not been completedand the relationship of noduiation andN2(C2H2) valuestototal nitrogen are not known.The rapid increase in nitrogen fixation duringthe growing season corresponds to the time offruit formation and filling, and the decreasecorresponds to maturation.These data suggest that a single evaluation ofthe nitrogen fixing ability of a genotype usingacetylene reduction if taken during the period ofpeak activity might be effective for preliminaryscreening of genotypes for nitrogen fixation.However, selection using total nitrogen accumulatedor dry matter accumulated throughFigure 1. Means of cultivars for nitrogenaseactivity (µ mol C2HAIplant per hr)over harvest dates (Clayton 1978).104

Figure 2.Means of cultivars for nodulation(nodule number/plant) o ver harvestdates (Clayton 1978).the growing season is almost certain to be moreeffective than N2(C2H2) measured once or evenseveral times during the growing season. However,several N2(C2H2) measurements duringthe growing season might be useful in choosingparents. Two lines producing similar amountsof nitrogen but having different peak periods ofactivity as determined by acetylene reductionmight produce transgressive segregates.Late Generation: FieldThirty F4 generation lines from a Virginiax Spanish cross were grown at two fieldsites in order to determine the genetics of traitsindicating nitrogen fixation for a population oflate generation lines. The Virginia parent (NC-6),a high yielding Virginia cultivar, is well nodulatedby the indigenous rhizobial strains inNorth Carolina, while the Spanish parent (922)is poorly nodulated. Plot means for N2(C2H2)fixed, nodule number, nodule weight and dryweight of plant were analyzed considering locationsand entries as random effects. Althoughthe study when completed will consist of severalsampling dates over years, parental andline means for one sampling date 90 days afterplanting suggest that sufficient variability existsfor progress from selections in this population(Table 12). The Spanish line is lower in nodulation,has less nitrogenase activity and smallerplant weight than the Virginia parent. The rangeof means for the 30 lines generally equal orexceed the range of the parents. Genotypicvariance was estimated from the varianceamong the means for the 30 late generationlines. These estimates were used to estimateheritability as follows:Quantitative Geneticsof Nitrogen FixationWe have investigated the genetic control ofnitrogen fixation using a diallel cross in thegreenhouse and a population of late generationlines in the field.Early Generation: GreenhouseThe F1 generation of a diallel cross of 10 cultivarsfrom South America was evaluated in ananalysis of gene action for traits related tonitrogen fixation. Hybrid progenies were significantlydifferent for all traits (Table 11). Generalcombining ability, which is usually indicativeof additive gene action, was significant andgreater than specific combining ability for nodulation,N2(C2H2) fixed, plant weight, nitrogencontent and total nitrogen. Correlations betweenparental and general combining abilityeffects were nonsignificant for all traits, sosimple evaluation of lines for nitrogen fixingcapacity in the greenhouse may not identifysuperior parents for use in breeding programs.Where: oG = estimate of genotypic variance,= estimate of error variance, andHeritability estimates ranged from 0.45 fornodule numberto0.80forN2(C2H2) fixed (Table13). These estimates indicate that selection fortraits indicative of nitrogen fixation should beeffective for this population. Selections will bemade and the response to selection for nitrogenfixing traits and the effect of selection fornitrogen fixation on productivity will be determined.An Alternative Breeding StrategyIt has been suggested that the nitrogen fixationin the field may be limited to a large extent bythe availability of photosynthate. Enrichment ofthe atmosphere in the foliar canopy of105

Table 11. Maan squares from the diallal analysis of characters Indicative of nitrogan-fIxlng ability.Nodule Nitrogenase Plant Nitrogen TotalNodule mass activity weight content nitrogenSource df number (mg) ( µmnol C2H4/plant per hr) (g) (%) (mg/plant)Blocks 3 4742** 64505** 73.85** 7.85** 0.5965** 5780**Genotypes 98 1477** 10030** 6.47** 1.92** 0.1418** 2190**Parents 9 726 8543 6.09 0.60 0.1508 534Hybrids 88 1562** 10132** 6.58** 2.08** 0.1423** 2378**General Combining Ability 9 4216** 26950** 17.10** 3.72** 0.4910** 3327**Specific Combining Ability 35 1533** 263** 4.68 1.97** 0.0699 2252**Maternal 9 1433** 16796** 3.74 2.32** 0.2197** 3674**Reciprocal 35 941 5964 6.50* 1.69 0.1052 1954**Parents vs hybrids 1 723 14423 0.08 0.27 0.0143 479Error 280 742 4825 3.97 0.53 0.0845 619Table 12. Parental means and range of means for single sample 90 days after planting ofgroundnut parents and F4 generation population.Means over locationsIdentityNodulenumberNoduleweight(g)Nitrogenase activity( µmol C 2H 4/plant per hr)Plantdry weightSpanish parent (922)Virginia parent (NC 6)F 4lines255474152-3910.2450.5180.156-0.4531.7834.0281.112-4.10320.329.912.7-29.5Table 13.TraitHerltaboility estimates for nitrogenfixation traits for late generationlines from cross of Spanish and Virginialines sampled 90 days afterplanting.Nodule numberNodule mass (dry wt/plant in g)N2 (C2H2) in µmol C 2H 4/plant per hrDry weight/shoot (g)Estimate0.450.630.800.74groundnuts with 1500 ppm carbon dioxide duringdaylight hours increased nitrogen fixation,measured by the acetylene reduction assay, by60% and also increased plant growth and nodulationsupposedly because of larger amounts ofavailable photosynthate (Hardy and Havelka1976; Havelka and Hardy 1976). Diurnal studiesand shading experiments at ICRISAT (Dart1977) and leaf removal studies at North Carolina(unpublished) also suggest that the rate ofnitrogen fixation is governed by the availabilityof photosynthate. Once the groundnut plantenters the reproductive stage the nodules, as aphotosynthate sink, must compete not onlywith the growing vegetative parts, but also withthe developing fruit. Hardy et al. (1971) reportedthat over 90% of the total amount of nitrogenfixed occurred during the period of fruit formationand maturation with rate of fixation enteringan exponential phase at or about the time ofpegging. Since variation in photosynthetic ratesand net photosynthate accumulation has beendemonstrated for groundnuts (McCloud et al.1977; Pallas and Samish 1974; Pallas 1973;Williams et al. 1975; Emery et al. 1973), it shouldbe possible to select photosyntheticallysuperior genotypes which fix more nitrogen.Preliminary analysis of several field studiesconducted in North Carolina indicates that thereis adequate variability in net photosyntheticefficiency (biological yield) to select genotypesthat are more efficient in accumulation ofphotosynthate (Ball et al. 1979). Furthermore,106

we have found biological yield (total dry matter),economic yield (fruit) and nitrogen fixedN2(C2H2> to be positively correlated (r =.48**-.72** with 38 df). This suggests thatgroundnut breeders can indirectly select forgreater nitrogen fixation by selecting for biologicaland/or economic yield. Thus selection foreconomic yield may be an effective method ofincreasing nitrogen fixation when groundnutsare well nodulated by native rhizobia. Thishypothesis is presently being tested in studiesat North Carolina.S u m m a r yThe atmospheric nitrogen fixed by groundnutscan be increased dramatically by the selectionand use of effective strains of Rhizobium if thegroundnut plants are poorly nodulated or nodulatedwith ineffective strains. Because of asignificant genotype x strain interaction, thehost genotype must be considered in strainselection. Strains can be selected after theyhave shown broad adaptation in symbiosis witha number of diverse host genotypes or theymay be selected in symbiosis with the singlehost genotype to be grown.Sufficient variability exists for selection ofhost genotypes with greater nodulation andgreater nitrogen fixing potential. Preliminaryestimates of heritability for late generation linesfrom a Virginia x Spanish cross suggest thatselection should be effective for traits indicativeof nitrogen fixation. However, since biologicalyield and economic yield appear to be correlatedwith nitrogen fixation, it may be possibleto select for higher nitrogen fixation by selectingfor biological yield and/or economic yield.ReferencesALBRECHT, H. R. 1943. Factors influencing the effect ofinoculation of peanuts grown on new peanut lands.Proceedings of the Soil Science Society of America8: 217-220.ALLEN, 0. N„ and ALLEN, E. K.. 1940. Response of thepeanut plant to inoculation with rhizobia with specialreference to morphological development of thenodules. Botanical Gazette 102: 121-142.BALL, S. T., WYNNE, J. C, and ISLEIB, T. G. 1979. Netphotosynthetic efficiency and partitioning of photosynthatein peanut cultivars (Abs.). Proceedings ofthe American Peanut Research and Education Association11: 43.BERENYI, N. 1962. Some influences of nitrogen fertilizationand seed inoculation with rhizobia on thegrowth and nitrogen fixation of peanuts. M. S.thesis, Dept. of Soil Science, North Carolina University,Raleigh, USA.BURRILL, T. J., and HANSEN, R. 1917. Is symbiosis possiblebetween legume bacteria and nonlegumeplants? Illinois Agricultural Experiment Station Bulletin202.BURTON, J. C. 1976. Pragmatic aspects of theRhizobium leguminous plant association. Pages429-446 in W. E. Newton and Nyman, C. J., (ed.),Proc. of the 1st International Symposium on NitrogenFixation. Volume 2. Washington State UniversityPress, Pullman.CARROLL, W.. R. 1934. A study of Rhizobium species inrelation to nodule formation on the roots of Floridalegumes. I. Soil Science 37: 117-134.CHOMCHALOW, S. 1971. The effectiveness of introducedRhizobium strains on 'Rayong' peanut. ThailandJournal of Agricultural Science 4: 85-94.COLLINS, W. O. 1943. Preliminary report on legumeinoculation studies. Soil Science Society of AmericanProceedings 8: 221-222.DADARWAL, K. R., SINGH, C S., and SUBBA RAO, N. S.1974. Nodulation and serological studies of rhizobiafrom six species of Arachis. Plant Soil 40: 535-544.DART, PETER. 1977. Advisory group meeting on thepotential use of isotopes in the study of biologicaldinitrogen fixation. The ICRISAT MicrobiologyProgram, Hyderabad, India. November 21-25.DENARIE, J. 1968. Inoculation des legumineuses aMadagascar. Ann. Agron. 19: 473-496.DOKU, E. V. 1969. Host specificity among five speciesin the cowpea crossinoculation group. Plant Soil30: 126-128.DUGGAR, J. F. 1935a. The nodulation and other adaptationsof certain summer legumes. Journal of theAmerican Society of Agronomy 27: 32-37.DUGGAR, J. F. 1935b. The effect of inoculation andfertilization on the Spanish peanuts and root nodulenumbers. Journal of the American Society of Agronomy27: 128-133.107

DUGGAR, J. F. 1935c. Modulation of peanut plants asaffected by variety, shelling of seed and disinfectionof seed. Journal of the American Society of Agronomy27: 286-288.ELKAN, G. H., WYNNE, J. C, SCHNEEWEIS, T. J., andISLEIB, T. G. 1980. Field inoculation of peanuts withsingle strain isolates of Rhizobium. Peanut Science(in review).EMERY, D. A., WYNNE, J. C, and RICE, P. W. 1973. Canreproductive efficiency in cultivated peanuts be improved?Oleagineux 28: 399-403.ERDMAN, L. W. 1943. New developments in legumeinoculation. Soil Science Society of America Proceedings8: 213-216.GAUR, Y. D., SEN, A. N„ SUBBA RAO, N. S. 1974a. Problemregarding groundnut (Arachis hypogaea L.) inoculationin tropics with special reference to India.Indian Academy of Science Proceedings40(5): 562-570.GAUR, Y. D., SEN, A. N., and SUBBA RAO, N. S. 1974b.Promiscuity in groundnut Rhizobium association.Zbl. Bakt. Abt. II: 129-369.HARDY, R. W. F., and HAVELKA, U. D. 1976. Photosynthateas a major factor limiting nitrogen fixation byfield-grown legumes with emphasis on soybean,Pages 421-439 in P. S. Nutman (ed.), Symbiotic NitrogenFixation in Plants IBP7. Cambridge UniversityPress, Cambridge, Maryland, USA.HARDY,R.W.F., BURNS, R.C.,HEBERT,R.R.,HOLSTEN,R.D., and JACKSON, E. K. 1971. Biological nitrogen fixation:Pages 561-590 in A key to world protein. PlantSoil. Sp. Vol.HAVELKA, U. D., and HARDY, R. W. F. 1976. N2(C2H2)fixation, growth, and yield response of field-grownpeanut (Arachis hypogaea L.) when grown underambient and 1500 ppm COs in the foliar canopy.Page 72 in Agronomy Abstracts.HAWAII, UNIVERSITY OF.1978. Catalogue of strains fromthe NifTALAL Rhizobium collection (abbreviated). Paia,Maui, Hawaii.ISWARAN, V., and SEN, A. 1974. Some studies on thegroundnut Rhizobium symbiosis. Zentralbl. BakteriolParasit Infektionskr Hyg., Zweite NaturwissAbstracts 129(5): 477-480.KUMARA RAO,J.V.D.,SEN,A.,andSHENDE,S.T. 1974.Inhibition of groundnut Rhizobium in Indian soils.Indian Academy of Science Proceedings40(5): 535-539.LOPES, E. S., LOVADINI, L A. C, MIYASAKA, S., IGUE, T.,and GIARDINI, A. R. 1974. Selection of strains ofRhizobium species for peanuts (Arachis hypogaeaL.) and Galactia striata (Jacq.). Urban. Bragantia33: CV-CX.MCCLOUD, D. E., DUNCAN, W. G., and MCGRAW, R. L1977. Physiological aspects of peanut yield improvement.Page 90 in Agronomy Abstracts.MOSTAFA, M. A., and MAHMOUD, Z. M. 1951. Bacterialisolates from root nodules of Zygophyllaceae. Nature(Lond.) 167: 446-447.PALLAS, J. E., Jr. 1973. Diurnal changes in transpirationand daily photosynthetic rate of several cropplants. Crop Science 13: 82-84.PALLAS, J. E., Jr. and SAMISH, Y. B. 1974. Photosyntheticresponse to peanut. Crop Science 17: 478-482.PANT, S. D., and ISWARAN, V. 1970. Survival ofgroundnut Rhizobium in Indian soils. Mysore Journalof Agricultural Science 4: 19-25.RAJAGOPALAN, N., and SADASIVAN, T. S. 1964. Someaspects of root nodulation in tropical legumes. CurrentScience 33: 197-202.RAJU, M. S. 1936. Studies on the bacterial-plantgroups of cowpea, Cicer and Dhaincha. I. Classification.Abl. Bakt. Abt. II 94: 249-262.SCHIFFMANN, J. 1961. Field experiments on inoculationof peanuts in northern Negro soils. Israel Journalof Agricultural Science 11: 151-158.SCHIFFMANN, J., and ALPER Y. 1968a. Effects ofRhizobium-inoculum placement on peanut inoculation.Experimental Agriculture 4: 203-208.SCHIFFMANN, J., and ALPER Y. 1968b. Inoculation ofpeanuts by application of Rhizobium suspensioninto the planting furrows. Experimental Agriculture4: 219-226.SCHIFFMANN, J., and LOBEL R. 1970. Haemoglobin determinationand its value as an early indication ofpeanut Rhizobium efficiency. Plant Soil 33: 501-512.SHIMSHI, D., SCHIFFMANN, J., KOST, Y., BIELORAI, H., andALPER, Y. 1967. Effect of moisture regime on nodulationof inoculated peanuts. Agronomy Journal59: 397-400.USDA, Cell Culture and Nitrogen Fixation Lab. 1979.USD A — Beltsville Rhizobium culture collectioncatalogue. Beltsville, Maryland, USA.108

VlDHYASEKARAN, P., BALARAMAN, K., DEIVEEGASUN-DAAUM, M., and RANGASWAMI, G. 1973. Relationshipbetween virulence and auxin production byRhizobium isolates from groundnut. Current Science42(2): 66-67.WACEK, T. J., and ALM, D. 1978. Easy-to-make Leonardjar. Crop Science 18: 514-515.WALKER, R. H. 1928. Physiological studies on the nitrogenfixing bacteria of the genus Rhizobium. IowaAgricultural Experiment Station Bulletin 113.WEAVER, R. W. 1974. Effectiveness of rhizobia formingnodules on Texas grown peanuts. Peanut Science1: 23-25.WILLIAMS, J. H., WILSON, J. H., and BATE, G. C. 1975. Thegrowth and development of four groundnut{Arachis hypogaea L.) cultivars in Rhodesia. RhodesianJournal of Agricultural Research 13: 131-144.WYNNE, J. C, ELKAN, G. H., MEISNER, C. M., SCHNEEWEIS,T. J., and LIGON, J. W. 1980. Greenhouse evaluation ofstrains of Rhizobium for peanuts. Agronomy Journal72: 645-649.WYNNE, J. C ELKAN, G. H., SCHNEEWEIS,T. J., ISLEIB,T.G.,PRESTON, C. M., and MEISNER, C. A. 1978. Increasingnitrogen fixation of the peanut. Proceedings ofthe American Peanut Research and Education Association10: 22-29.109

Studies on Nitrogen Fixationby Groundnut at ICRISATP. T. C. Nambiar and P. J. Dart*Symbiotic nitrogen fixation depends on aninteraction between the Rhizobium strain, hostplant genome and environment. We are examiningall the three components with the objectiveof increasing biological nitrogen fixation bygroundnut.Rhizobium: Isolation, StrainTesting and InoculationResponseGroundnut is promiscuously nodulated byRhizobium of the cowpea miscellany (Fred et al.1932). When nodulated with effective (nitrogenfixing) rhizobia, groundnut nodules fix most ofthe nitrogen requirements of the plant (Pettitet al. 1975; Schiftman et al. 1968). Substantialincreases in the yield have been obtained followinginoculation in fields where peanuts hadnot been grown before (Burton 1976; Pettit et al.1975; Schiftman et al. 1968; Sundara Rao 1971).In fields where groundnuts had been grownearlier, inoculation sometimes resulted in increasedyield, increase in seed quality, higherprotein and oil content (Arora et al. 1970;Chesney 1975). A decrease in yield followinginoculation has also been reported (Subba Rao1976). Allen and Allen (1940) described differencesbetween Rhizobium strains in nodulationand nitrogen fixation in groundnut. Surveys infarmers' fields in the southern states of Indiashowed considerable variation in nodulationwith 52 out of 96 fields surveyed having poornodulation. Nodulation and nitrogen fixing activity,as measured by acetylene reduction, wasten times less in some farmers' fields than thatobserved in fields at ICRISAT Center at the samestage of growth of the plant. These observationsindicate that it should be possible to increase* Microbiologist and Principal Microbiologist respectively,Groundnut Improvement Program, ICRISAT.biological nitrogen fixation in these fields byinoculating with effective and competitiveRhizobium strains.We collected nodules from farmers' fields inKarnataka and Andhra Pradesh states in Indiaand from them have purified 50 authenticatedRhizobium strains. We also maintain a collectionof Rhizobium strains for groundnut obtainedfrom all other known major collections inthe world such as USDA (Beltsville), NorthCarolina State University (Raleigh), NifTAL(Hawaii), Dept. of Agriculture, Zimbabwe, andthe Australian Inoculants Research and ControlService. As a part of our collaborative projectwith North Carolina State University (NCSU) onbiological nitrogen fixation, we are testing thesuitability for use as inoculants of Rhizobiumstrains which have been isolated and characterizedat NCSU from nodules obtained duringArachis germplasm collection trips in SouthAmerica (Wynne et al. these Proceedings).Our experiments show that in nitrogen-freesand: vermiculite media in pots, Rhizobiumstrains vary in their ability to nodulate and fixnitrogen with groundnut (Figs. 1, 2). Althoughthe magnitude of the shoot dry weight wasoften related to nodule dry weight (e.g. strain IC6006, Figs. 1, 2), this relationship was notconsistent with the array of the strains. Becauseof the variability in germination in Leonard jars,pot culture assembly was used for strain testing.We sterilize by autoclaving or steaming orheating to 150° C the rooting media and applynitrogen-free nutrient solution through a permanent6 cm diameter watering tube which iscovered with a metal cap when not in use. Thepot surface is covered with heat-sterilized gravel(3-6mm) to protect from aerial contamination(Fig, 3). Six seeds are sown per pot and thinnedto three plants/pot.We have observed a relationship betweenshoot growth, and the amount of inoculumapplied up to 10 7 Rhizobium per seed when110

Figure 1. Shoot production by groundnut inoculated by different Rhizobium strains. Three plantsper 20 cm dia pot were grown in a sand.vermiculite (2:1) medium, inoculated with brothculture at the rate of 10 s rhizobialseed, watered with nitrogen-free nutrient solution andharvested 64 days after planting. Controls received no inoculum; NO3-C received 240ppm N continuously.groundnut was grown in pots of sterilized sand:vermiculite. Nodulation followed the sametrend (Table 1). This is in marked contrast to thesituation in soybeans where nodulation andplant growth was reduced in both field and pottrials only if the inoculum was less than15 x 10 3 per seed (Burton 1975). This indicatesthat one has to ensure an adequate Rhizobiuminoculum size in pot trials measuring nitrogenfixation. It also demonstrates the need toexamine the interaction between inoculum sizeand nodulation response in field experiments.Groundnut and soybean differ in the infectionprocess in nodule formation (Dart 1977), andthis may be the cause of the difference inresponse to inoculum size.Table 2 summarizes the results of eight inoculationtrials at ICRISAT Center. Although aresponse was not always obtained, Robut 33-1,a cultivar which is about to be released inAndhra Pradesh, gave substantial increases inpod yield when inoculated with a strain NC 92.Strain NC 92 was obtained from NCSU andisolated from nodules collected in South111

Figure 2. Nodule formation by different Rhizobium strains. Conditions as in Figure 1.America. Robut 33-1 was the variety which mostcommonly responded to inoculation and in twoof the inoculation trials this response was bestwith strain NC 92. It may be worth developingan inoculum with NC 92 specifically for use withRobut 33-1 provided the evidence of poor competitionability against strain IC 6009 (Table 3) isnot found with other Rhizobium strains.Since seed treatment with fungicides is arecommended practice, the inoculum forgroundnut needsto beseparated from the seed.We do this by applying a granular inoculumbelow each seed, the granules being made byinoculating 1-2 mm sand particles with peatinoculum using methyl cellulose as the sticker.Nitrogen Fixation by GroundnutNitrogenase Activity AssayWe have studied several parameters thatinfluence acetylene reduction by groundnutroot nodules in our efforts to standardize theassay for measu ring nitrog enase activity of fieldgrown plants. There is a marked diurnal variationin the nitrogenase activity of field grownplants (Fig. 4). The increase in activity afterdaybreak suggests a close link with photosynthesis.Thus plants which produce more photosynthateare likely to fix more nitrogen. It will beinteresting to see if photosynthesis declines in112

Table 1. Influanca of RMxoblum Inoculumlevel on nodulation and nltroganfixation by groundnut.Level of Rhizobiumapplied as broth Shoot dry wt* Nodule dry wt*(number/seed) (g/plant) (g/plant)3.2 x 10 9 3.38* 0.13 a5.5 x 10 7 2.38* 0.12 a4.8 x 10 4 1.08* 0.03*6.1 x 10 2 0.97* 0.02*Nitrate control 4.34 0Figure 3.Cross section of a pot system.* Data in each column followed by the same letter are notsignificantly different at the 0.05 level.Note: Kadlrl 71-1 plants inoculated with strain NC-92 weregrown under semlsterile conditions watered withnitrogen-free nutrient solution and harvested 57 daysafter planting.Table 2.Summary of Inoculation trials conducted at ICRISAT Center.Year/Season Soil type Cultivars Strain Pod yield responseRainy season1977Rainy season1977Rainy season1977Rainy season1978Rainy season1978Postrainyseason 1979Rainy season1979Postrainyseason 1980HF, AlfisolTMV-2Kadiri 71-1LF, Alfisol Kadiri 71-1Robut 33-1, TMV-2HF, Vertisol Kadiri 71-1TMV-2HF, Alfisol Robut 33-1ArgentineAH-8189LF, AlfisolHF, AlfisolMH-2ArgentineRobut 33-1MH-2Robut 33-1AH-8189HF, Alfisol Kadiri 71-1Robut 33-1AH-81895a/70 Nil5a/70 TMV-2, 25%, Robut 33-1, 32%5a/70IC 60065a/70ICG-60IC6006Mixture5a/70ICG-606S MixtureNC92IC6009Mixture5a /70IC6006NC 43.3NC7.2NC92NilNilRobut 33-1, 26% (NS)Robut 33-1, 28.5% (NC 92)Robut 33-1, 25.7% (NC 92)HF, Alfisol Robut 33-1 NC92 NilHF - High Fertility LF = Low Fertility113

Table 3.Response of groundnut to Rhixobium Inoculation In an Alfisol ( 1 9 7 8 - 79 postrainyseason).Pod w light (kg/ha)Cultivars Uninoculated IC-6009 NC 92Mixture(IC 6009 + NC 92)MH-2Robut 33-1AH-818922223500283318883333286119444500**269420272805*2805CV (%) 15.51 **Slg nilficant at 1% level *Significant at 5% levelTable 4. Mean squares from Anova fornltrogenase activity (µ moles C2H4/plant par hr) of selected germplasmlinea assayed during day and again atnight.Source of variation df Mean squareReplicationTime of assayGermplasm linesInteractionExperimental error** Significant at 1% level311313815500**374254**16314**5659**1321Figure 4,Nitrogenase activity ( µmol C2H4/gdry weight of nodule per hour) ingroundnut cultivar Kadiri 71-1. after81 days of planting, ICRISA T Center,postrainy season 1976.the same way as nitrogenase activity in theearly afternoon, when leaf vapor pressuredeficits are likely to be greater. A preliminaryacetylene reduction assay of 14 groundnut linesselected for variability in foliage production,showed significant interaction in acetylene reductionbetween lines and time of measurementof nitrogenase activity — day time assayat 0900-1100 hr and night time assay at 2100-2300 hr (Table 4).Temperatures in the assay bottle greater than25° C decreased nitrogenase activity of nodulatedroots of groundnut cv Kadiri 71-1 (Table5). Excess or insufficient moisture also de-Table 5. Effect of incubation temperature onacetylene reduction by peanut roots.Incubationtemperatureµmoles C2H4/plant per hr25°C 46.3430°C 33.9735°C 32.52CV (%) 42LSD (0.05) 9.8creased acetylene reduction activity (Fig. 5). Wehave observed that shading causes a rapiddecrease in nitrogenase activity. When 109-dayold Kadiri 71-1 plants were shaded to 60% ofambient light intensity, nitrogenase activity wasreduced within a day by 30% (Fig. 6). Plantsgrown during the dry season, which receivedfewer irrigations but were not allowed to wilt,produced about half the pod yield of plantsirrigated every 7-10 days. There were indica-114

Figure 5.Effect of soil moisture on nitrogenase activity. Sixty days old Kadiri 71-1 plants wereassayed on different days after an irrigation.tions of differences between varieties in responseto water stress. Nodule developmentand nitrogenase activity were much reduced bythe water stress. Nitrogenase activity recoveredrapidly after an irrigation.Seasonal and Cultivar DifferencesFigure 7 shows the nodulation and nitrogenfixing activity of cv Kadiri 71-1 (A hypogaeasubsp hypogaea, a long-season runner cultivar)and of cv Comet (A hypogaea subsp fastigiata,a short duration erect-bunch cultivar) whengrown in the rainy season 1976 and underirrigation in the postrainy season 1977. In 1976,a 57 day dry period beginning 39 days afterplanting had an overriding effect on noduleformation and nitrogenase activity. For therainy season planting, nodules formed rapidlyduring the first 25 days, but the drought restrictedfurther nodule formation with littledifference between cultivars. For Comet,nodules changed little in size after 25 days butfor Kadiri 71-1, nodules continued to grow sothat by 75days nodule mass per plant was twicethat of Comet.In the postrainy season, nodule formationwas slower to start but then increased until 80days after planting when three times as manynodules had formed as in the rainy season. Newnodules were still forming on Kadiri 71-1 at 128days. Nodule dry weight per plant reflected thepattern for nodule number.Nitrogenase activity per plant and the efficiencyof the nodules (nitrogenase/g noduletissue) differed significantly between cultivars115

Figure 6.Effect of shading on nitrogenase activity of groundnut. Plants grown as an irrigated cropwere shaded in replicated plots at 109 days after planting. Acetylene reduction assayswere carried out on the same day and on a subsequent day. | indicates the start ofshading treatment.and seasons. In rainy season 1976, nitrogenaseactivity was at a maximum by 25 days, but fromabout 40-70 days, Kadiri 71-1 nodules weremore active than those of Comet. It was onlyafter 40 days without appreciable rainfall thatthe nitrogenase activity of Kadiri 71-1 nodulesdecreased. The pattern of nitrogen fixation inthe irrigated season was quite different, increasinguntil about 75 days, then decreasing rapidly,with differences developing between cultivars.Kadiri 71-1 nodules at 128 days were still moreactive than at any stage during the rainy season.Peak activity per plant during the irrigatedpostrainy season was more than twice that ofthe rainy season.The difference in symbiotic performance ofKadiri 71-1 and Comet under the drought stressof 1976, as well as between seasons, suggeststhat we can select cultivars which are betteradapted to fix nitrogen under stress conditions.Nodulation and nitrogen fixation of two cultivarsMH-2, a dwarf mutant, and Kadiri 71-1was followed throughout the postrainy season(Figs. 8, 9). There were marked differences inthe weight of the nodules per plant and nitrogenaseactivity per plant of these two cultivars.Except for a short period, however,nitrogenase activity per gram of shoot weightwas very similar for the two cultivars (Fig. 10).This may indicate that in dwarf cultivars such as116

Figure 7.Seasonal variation in nodule number and nodule weight per plant and nitrogenaseactivity per gram nodule weight and per plant in cv Kadiri 71-1 and Comet grown duringrainy season 1976 and postrainy season 1977 at ICRISAT Center. The postrainy seasonplanting was irrigated.117

Figure 9. Nitrogenase activity of Kadiri 71-1and MH-2 during irrigated postrainyseason.Figure 8.Nodulation of Kadiri 71-1 and MH-2during irrigated postrainy season.MH-2, nitrogen fixation is limited by photosynthatesupply, if we assume that net photosynthesisand plant top dry weight are correlated.Effect of IntercroppingDuring the 1978 rainy season, we observed thatgroundnuts when intercropped with pearl millet,nodulated poorly and fixed less nitrogenthan the sole crop (Fig. 11). Three rows ofgroundnut were intercropped with one row ofmillet which, as commonly practiced, received Nfertilizer at the rate of 80 kg N/ha, a level givingnear optimum intercrop advantage. During the1979 rainy season (Table 6) we observed a similartrend in groundnut intercropped in a normallyspaced maize stand (two rows of groundnutbetween maize rows). Interestingly, solegroundnut and groundnut intercropped withmaize which received no N fertilizer, had similarnodule number and nitrogenase activity.The decrease in nitrogenase activity in intercroppedgroundnut could be due to: (1) theinhibition of nodulation by the nitrogen fertilizeradded to the cereal crop (we have observed thatfertilizer nitrogen reduces nodulation and nitrogenfixation), and/or (2) the light available tothe groundnut in the intercrop decreases asmore N fertilizer is added to the cereal.Observations from an experiment ingroundnut/sorghum intercropping where differentshading intensities were created by gradeddefoliation of the sorghum support this (Table7).We plan to study the intercropping systemmore carefully. It may be possible to increasethe nodulation and nitrogen fixation of intercroppedgroundnut by selecting cereal cultivarswhich allow more light to the groundnut. It mayalso be possible to select groundnut cultivarsmore tolerant of reduced light availability. Anideal cereal/legume intercropping situationwould utilize the maximum nitrogen fixationability of the legume while minimizing nitrogenfertilizer addition to the cereal (for other detailsof these intercropping experiments, see Reddyet al. these Proceedings).118

Figure 11. Nitrogenase activity of sole andintercropped groundnut.Figure 10. Nitrogenase activity per gram oftop dry weight for Kadiri 71-1 andMH-2 during irrigated postrainyseason.We have not observed any interaction amongfive groundnut cultivars for nodulation andnitrogen fixation in intercrop and sole crop(Table 7). In soybeans it has been suggestedthat urea has a less harmful effect on nodulationthan nitrate (Harper 1975). We plan to study theeffect of different sources of N fertilizer appliedto the cereal crop and their effect on nodulationand nitrogen fixation of groundnut as the intercrop.Residual E f f e c t sRainy season groundnut, when compared withTable 6. Nodulation and nltrogen fixation bygroundnut intercropped with maize.Nodule µ moles C 2H4/Treatment Number/plant plant per hrSole groundnut 171 21.3Intercropped groundnutNitrogen added to maize(kg/ha)0 164.70 20.1050 159.50 9.36100 150.0 7.00150 134.15 3.52CV (%) 19.71 30.30LSD (0.05) 18.90 5.75maize, had a large positive residual effect ongrowth and yield of millet in the subsequent,irrigated postrainy season with an increase inyield of 650 kg/ha, i.e., 45%. All groundnutand above-ground maize material and thegroundnut main roots were removed from thefield prior to the millet planting. This seems tobe an effect of groundnut on N uptake by themillet, and would be consistent with the extremelyhigh nitrogen fixation rates associatedTable 7.Nitrogenase activity of sola and Intercroppedgroundnut.Nitrogenase activity a(µmoles CzH4/plant per hr)Intercrop Intercrop(low (highCultivars Sole crop density) density)Chico-17200 15.2 11.8 6.8TMV-2 18.1 12.6 8.3MK-374 25.8 23.6 12.2MH-2 15.4 7.9 9.1Gangapuri 15.7 10.6 6.5CV (%) 42a. Intercrop treatment effects ere significantly different for allcultivars.Note: Groundnut end sorghum were planted in a ratio of 2:1in the Intercrop. Low density Intercrop wes obtainedby removing alternate pairs of leaves of sorghum.Plants were hervested 70 days after planting. Sorghumwas fertilized with 80 kg N/ha.119

with groundnut. The effect could be due to the Nleft in fine roots in the soil or due to exudation ofN into the soil or due to less removal of availablesoil N by groundnut when compared with maize(Table 8).Genetic Variabilityin Groundnut GermplasmLines for NodulationVarietal differences in nodulation amonggroundnut were reported by Duggar as early as1935(Duggar 1935). We found large differencesamong germplasm lines for nodulation (noduledry weight) and nitrogenase activity during the1977-78 postrainy season and the 1978 rainyseason. The data on nodule weight and nitrogenaseactivity were analyzed by the Scott-Knott procedure (Gates et al. 1978). Theclusters formed were classified into low,medium, and high nodulating and nitrogenfixing (as measured by acetylene reduction)lines (Tables 9, 10). The comparison over seasonindicated an interaction between cultivarand season for nodulation and nitrogen fixation.Similar host plant differences in nodulationand N2 (C2H 2) reduction have been documentedin North Carolina peanut fields containing nativerhizobia (Wynne et al. these Proceedings).From the variation present in the germplasmlines, it seems possible to develop genotypeswith greater nitrogen fixing ability by selectingparents that consistently have high nitrogenfixing ability over seasons. Isleib et al. (1978)from a 10 x 10 diallel study indicated significantadditive gene action for nodulation, nitrogenaseactivity and plant weight.We have also found groundnut cultivarswhich consistently nodulate on the hypocotyl,often with a subtending lateral root, whereasothers form few or no nodules in this region(Fig. 12). For example, during the 1977 rainyseason, cv NC Acc 10 formed 175 nodules perplant on the hypocotyl (23% of the total nodulesformed) whereas cv NC Acc 770 formed only 12nodules (2% of the total) in this region. Somecultivars such as MK-374, nodulate further upthe stem, beyond the crown of the plant. Wehave observed that cultivars belonging to thebotanical variety hypogaea nodulated better inthe hypocotyl region than those from fastigiataTable 8.First cropGroundnutMaize unfertilizedMaize 20 kg N/haLSD (0.01)Residual effect of groundnut andmaize on millet grain yield in an Alflsol.aYield(kg/ha)198013251456360a Groundnut and maize grown In rainy season 1977 atICRISAT Center, followed by irrigated millet, In dry winterseason 1977-78.Table 9. Symbiotic characters ingroundnut germplasm entriesdays after planting).Range4 8(85Nodule number 247-628Nodule weight0.30-0.75 g/plant-'Nitrogenase activityµ mol C2H4 plant-'h- 1 36-176µ mol C2H4/gdry wt nodule/hr 95-386and vulgaris. We are presently studying theheritability of this location difference in noduleformation.Non-Nodulating GroundnutThe host-Rhizobium interaction in legumes iswell documented. The genetic basis for nonnodulationhas been described in soybeans, redclover and peas (Williams et al. 1954; Caldwell1966; Nutman 1949; Holl 1975). Recently GorbetandBurton reported non-nodulating lines ofArachis hypogaea (L) in the progenies of a cross48 7 A - 4 - 1 - 2 X PI 262090.During the 1978 rainy season we observedthat F2 plants in the rust screening nursery weresegregating for non-nodulation. All the parentsof the crosses were found to nodulate normally.Later during the rainy season in 1979, nonnodulatinglines were found in 14 additionalcrosses (Table 11). All these crosses have a rustresistant, Valencia groundnut as one of theparents [PI 259747; NC Acc 17090, EC 76446120

Table 10. Nodulation and acetylene reduction of groundnut cultivars.Postrainy season 1977-781st sampling2nd samplingRainy sceason 1978Botanical Nodu- Nitro- Nod il-Nitro-Nodu- Nitro-Cultivar ICG No. type lation genase lation genase lation genaseAh 3277 1218 Spanish L L L L L LAh 3275 1216 Spanish L L L L L LNo. 421 3158 Valencia L L L L - -Ah 39 1161 Spanish L L M H L LAh 5144 1235 Spanish L L M M M -NC Acc 888 359 Spanish L L L L M LAh 61 1173 Spanish L L L M L MAh 3272 1213 Spanish L L L M L MNo. 3527 1524 Spanish L - L M L -Faizpur-1-5 1102 Spanish L M L L M MNo. 418 1500,2202 Spanish L L L M - -NC Acc 1337 358 Valencia L L M M M LNC Acc 516 279 Valencia L - M M L -NC Acc 945 366 Valencia L L M M M -NC Acc 699 1630 Spanish L L L M L M148-7-4-3-12-B 1573 Spanish L - L M - -No. 1780 1508 Spanish L L M L -NC Acc 738 331 Valencia L - M M M--TG 17 2976 Spanish L L L M L LNo. 3270 1489 Spanish L L L L - -NC Acc 51 263 Valencia L M L L L -TG 8 95 Valencia L L M M L LAh 42 1163 Valencia L - M L MNC Acc 2651 402 Spanish L L L M M--NC Acc 1002 380 Valencia L - M M M -NC Acc 524 283 Valencia L M M M M MGAUG 1 - Spanish L - M M L LNC Acc 2734 420 Valencia L L M M M LNC Acc 495 1623 Spanish M M L M L LSpancross 3472 Spanish M - M M M LNC Acc 1286 389 Valencia M L M M M LNC Acc 17149 475 Valencia M L M M M MAh 1069 1196 Spanish M M M M L LKadiri 71-1Virginia M M M M L LrunnerAh 6279 2983 Spanish M - M M - -NC Acc 2600 400 Virginia M L M M L MBunchPOL 2 154 Spanish M M M M L LJH 171 3375 Spanish M M M M L LNC Acc 1303 393 Spanish M L M M M MNC Acc 975 376 Valencia M M M M M MSm-5 2956 Spanish M M M M L LContinued121

Table 10. ContinuedPostrainy season 1977--781st sampling 2nd sampling Rainy season 1978Botanical Nodu- Nitro- Nodu- Nitro- Nodu- Nitro-Cultivar ICG No. type lation genase lation genase lation genaseArgentine 3150 Spanish M M M L L LTifspan 3495 Spanish M M M L L LRobut 33-1 799 Virginia M M M M MBunch"Pollachi 1 127 Spanish M L M M M MNC Acc 17113 1699 Spanish M M M M M MAh 8254 2962 Spanish M M M M M LAh 7436 1547 Spanish M M M M M -NC Acc 490 274 Valencia M M M M M MX-14-4-B-19-B 1561 Spanish H M M M M -NC Ace 2821 2405 Virginia H M H M M MNC Acc 2654 404 Valencia H M M H M -Range of nodulation and nitrogenase activity for the clusters formedNodulation (g nodule/plant)Nitrogenfixation (µ moles C2H4/plant per hr)Low Medium High Low Medium HighSeason (L (M) (H) (L) (M) (H)Postrainyseason 19781 Sampling 0.08-0.11 0.11-0.16 0.188-0.19 16-28 30-44 -2 Sampling 0.3 -0.38 0.38-0.6 0.6 -0.75 36-64 65-132 166Rainyseason 1979 0.11-0.14 0.14-0.17 - 68-92 93-117 -Table 11. Crosses In which non-nodulatlngprogenies were observed.Shantung Ku No. 203 x NC Acc 17142NC Acc 2731 x NC Acc 17090NC Acc 2731 x EC 76446 (292)NC Acc 2768 x NC Acc 17090NC-17 x NCAcc 17090Shantung Ku No. 203 x NC Acc 17090Shantung Ku No. 203 x EC 76446 (292)Shantung Ku No. 203 x PI 259747NC-17 x EC 76446 (292)NC-F1a-14 x NC Acc 17090Rs-114 x NC Acc 17090NC-17 x PI 259747NC Acc 2731 x PI 259747Shantung Ku No. 203 x PI 259747Figure 12. Differential distribution of noduleson groundnut root. Left, cv NC Acc10 has many nodules on thehypocotyl. Right, cv NC Acc 770has only few nodules.122

(292]. Interestingly some segregants formedonly a few, very large nodules, much larger thanthe parents or normally nodulating F2 plants.Acetylene reduction assays showed that theirnitrogen fixing activity on a nodule weight basiswas similar to that of normal nodules on theparents. A preliminary genetic analysis basedon segregation for nodulation vs no nodulationshowed that a pair of independent duplicategenes control nodulation and that nonnodulationis governed by recessive genes(Nigam et al. 1980)Summary1. Groundnut yield can be increased by inoculatingwith Rhizobium.2. Nodulation and nitrogen fixation increasedwith increase in the number of Rhizobiuminoculum cells per seed.3. Nodulation and nitrogen fixation decreasedwhen groundnut was intercropped with millet,maize or sorghum.4. Photosynthesis is one of the major limitingfactors in nitrogen fixation as evidenced bydiurnal variation in nitrogenase activity, reductionof nitrogenase activity on shadinggroundnuts, and reduction of nitrogenaseto different degrees when groundnut isgrown in an intercrop with variable leaf areaindex of the companion crop.5. There is genotypic variation in nodulationand nitrogen fixation.6. Non-nodulating lines observed in the F2populations of some crosses have been purifiedand advanced to Fe.AcknowledgmentsIntercropping experiments were carried out incollaboration with Drs. M. S. Reddy, M. R. Rao,C. N. Floyd and R. W. Willey of the CroppingSystem Program and experiments on nonnodulatinggroundnut were conducted in collaborationwith Drs. S. N. Nigam and R. W.Gibbons of Groundnut Improvement Program.Wethank MrA.P.Ghugal,MrH. N. Ravishankarand Mr. B. Srinivasa Rao for their excellenttechnical assistance.ReferencesALLEN, O. N. and ALLEN, E. K. 1940. Response of thepeanut to inoculation with rhizobia with special referenceto morphological development of thenodules. Botanical Gazette 102: 121-142.ARORA, S. K., SAINI, J. S., GANDHI, R. C, and SANDU, R.S. 1970. Study of chemical composition and yield ofgroundnut as affected by Rhizobium inoculation.Oleagineux 25: 279-280.BURTON, J. C. 1975. Problems in obtaining adequateinoculation of soybeans. Pages 170-179 in Worldsoybean research. Ed. L. D. Hill; lllinoisilnterstatePrinters and Publishers.BURTON, J. C. 1976. Pragmatic aspects of theRhizobium: leguminous plant association. Pages429-446 in Proceedings of the First InternationalSymposium on Nitrogen Fixation, Vol 2. Eds. W. E.Newton, and C. J. Nyman. Pullman: WashingtonState University Press, USACALDWELL, B. E. 1966. Inheritance of a strain-specificineffective nodulation in soybeans. Crop Science6: 427-428.CHESNEY, H. A. D. 1975. Fertilizer studies withgroundnuts on the brown sands of Guyana. AgronomyJournal 67: 7-10.DART, P. J. 1977. Infection and development ofleguminous nodules. Pages 367-472 in A treatiseon dinitrogen fixation. Section III: Eds. R. W. F.Hardy and W. S. Silver. Wiley-lnterscience.DUGGAR, J. F. 1935. Nodulation of peanut plants asaffected by variety, shelling of seed and disinfectionof seed. Journal of American Society of Agronomy27: 286-288FRED, E. B., BALDWIN, I. L, and MCCOY, E., 1932. Rootnodule bacteria and leguminous plants. Universityof Wisconsin Studies 52: 34.GATES, C. E., and BILBRO, J. D. 1978. Illustration of acluster analysis method for mean separation. AgronomyJournal 70: 462-465.GORBET, D. W., and BURTON, J. C. 1979. A nonnodulatingpeanut. Crop Science 19: 727-728HARPER, J. E. 1975. Contribution of dinitrogen and soilor fertilizer nitrogen to soybean (Glycine max L.Merr) production. Pages 101-107 in World soybeanresearch. Ed. L. D. Hill, Illinois. Interstate Printersand Publishers.123

HOLL, F. B. 1975. Host plant control of the inheritanceof dinitrogen fixation in the Pisum-Rhizobium symbiosis.Euphytica 24: 767-770.ISLEIB, T. G., W Y N N E , J. C, E L K A N . G. H., andSCHNEEWEIS, T. J. 1978. Quantitative genetic aspectsof nitrogen fixation in peanut. Page 71 in Proceedingsof American Peanut Research and EducationAssociation.NIGAM, S. N., ARUNACHALAM, V . . GIBBONS, R. W., BAN-DYOPADHYAY,A.,andNAMBiAR, P. T. C. 1980. Geneticsof non-nodulation in groundnut (Arachis hypogaeaL). Oleagineux (in press).NUTMAN, P. S. 1949. Nuclear and cytoplasmic inheritanceof resistance to infection by nodule bacteria inred clover. Heredity 3: 263-291.PETTIT, R. E., WEAVER, R. W.,TABER, R. A., and STICHLER,C. R. 1975. Beneficial soil organisms. Pages 26-33 inPeanut production in Texas. Ed. J. E. Miller. TexasAgricultural Experiment Station, Texas A & M University,Texas, U.S.A.SCHIFTMAN, J., and ALPER, Y. 1968. Effects ofRhizobium-inoculum placement on peanut inoculation.Experimental Agriculture 4: 203-208.SUBBARAO, N. S. 1976. Field response of legumes inIndia to inoculation and fertilizer applications. Pages255-268//) symbiotic nitrogen fixation in plants. Ed.P. S. Nutman. Cambridge: Cambridge UniversityPress.SUNDARA RAO, W. V. B. 1971. Field experiments onnitrogen fixation by nodulated legumes. Plant andSoil. Special Volume: 287-291.WILLIAMS, L. F., and LYNCH, D. L. 1954. Inheritance of anon-nodulating character in the soybean. AgronomyJournal 46: 28-29.124

Physiological Basis for IncreasedYield Potential in PeanutsD. E. McCloud, W. G. Duncan, R. L. McGraw,P. K. Sibale, K. T. Ingram, J. Dreyerand I. S. Campbell*This work is part of a concerted effort at theUniversity of Florida and in Malawi to understandthe physiological basis for yield potentialin peanuts. While some idea of the yield potentialcan be obtained from a comparison ofrecent varieties with older ones, the yield formationprocess is dynamic, and one needs toconduct a growth analysis, taking frequent harveststhroughout the season, to understandcrop growth. Simulation modeling (Duncan etal. 1978) is necessary to understand thedynamics of yield formation.Peanut Production ModelDry-matter production in plants is derived fromsolar radiation through the photosynthetic process,and temperature governs the speed ofdevelopment (Fig 1.). There are three phenophasesin our peanut production model(PNUTS): expansion, podding, and filling. Theexpansion phenophase spans from emergenceuntil canopy closure when ground coverreaches 100%. Crop growth during this phaseis exponential, and is entirely vegetative.The podding phenophase begins 2 weeks* Professor, University of Florida, Gainesville,Florida, USA (USAID contract in Lilongwe,Malawi); Professor, University of Florida, Gainesville,Florida, USA; Assistant Professor, Universityof Minnesota, St. Paul, Minnesota, USA; SeniorResearch Officer, Ministry of Agriculture andNatural Resources, Lilongwe, Malawi; PostdoctoralResearch Assistant, University of Florida,Gainesville, Florida, USA; Chief Physiologist, Departmentof Agriculture and Technical Services,Potchefstroom, South Africa and formerlyGraduate Research Assistant, University of Florida,Gainesville, Florida, USA; International Intern,ICRISAT, Hyderabad, India, respectively.after the first flowers appear and in most of theimproved cultivars this coincides with the stagewhen full ground cover is reached. Pods areadded linearly until a full pod load has been set(Fig 2). The filling phase begins when a full podload has been set, and continues until maturity.To aid in understanding growth dynamics, wehave developed a computer simulation modelfor use with a small, hand-held minicomputer(Ingram et al. 1980). Two climatological inputs— total daily solar radiation and mean dailytemperature — are used to simulate dry-matterproduction. Other factors such as moisture, soilfertility and disease control are assumedadequate for optimum yields. Five equationsare used in our peanut production model.Temperature regulates the rate of crop developmentaccording to the developmentalunits required for each particular phenophase.Development units are accumulated by theformula:(1)where TEMP is mean daily temperature in °C.Daily assimilate is calculated as:DAS = RAD.PNE.GC (2)where RAD is expressed in MJ.m- 2 .day -1photosynthetic efficiency (PNE) = 1.0, with nofactors limiting photosynthesis. GC is theground cover coefficient. The ground covercoefficient is calculated by:(3)where is the sum of the developmentalunits from emergence, EXP is the expansionexponent, and DUE is thetotal developmentalunits for the expansion phenophase. Whenpodding begins, pod dry matter is calculatedby:PDM = DAS.PLPCF.PART (4)where PL is the pod load coefficient, PCF is the125

Figure 1. Diagrammatical representation of the peanut production model.pod composition adjustment factor (0.606) whichaccounts for the greater photosynthate neededto produce pods high in oil and protein contentcompared to the vegetative component. PARTis the ratio of daily assimilate flow to podscompared to the total assimilate.Vegetative dry matter is calculated by:VDM = DAS - (PDM/PCF) (5)When a full pod load has been set, filling beginsand it continues until maturity is reached. Poddry matter is calculated by equation (4) usingthe pod load coefficient of 1.0.Our objective for the peanut productionmodel is to simulate potential vegetative andpod dry matter production where the soil fertility,moisture, and plant pests are optimum formaximum productivity.Climatological andPhysiological InputsTwo climatological inputs — daily total solarradiation and mean daily temperature are usedin our peanut production model for calculatingpotential productivity. If desired, a soil moistureloop can be added as we have done for the IBMcomputer. However, we find potential productivitya useful measure of the uncontrollableclimatic factors.Physiological parameters which are inputinto the model are: the expansion exponent,developmental units for the expansion, poddingand filling phenophases, and the partitioningand pod weight factors. Initially in eachenvironment for each cultivar a growth analysisstudy with percent ground cover estimates,counts of pod numbers, and measurements ofvegetative and pod dry weights at weekly intervalswill be necessary. From these measurements,the developmental units for eachphenophase can be determined using equation(1).During the expansion phase, the expansionexponent should be selected by trial and errorgiving the best fit for the increase in vegetativedry weight — equation (3). We used an exponentof 2.5 for the Florida data. During thepodding phase, pod load increases in a linearrelation to I DU until a full pod load has beenset.126

HypotheticalThe physiological factors are then used asinitial inputs in the PNUTS model. For weeklygrowth analysis, weekly averages are computedfor temperature and solar radiation, andthese are then entered in the hand-heldminicomputer. Calculations of the weekly datafor each of the 19 harvests in our study takeabout 20 minutes. If a printer is used, much lesstime is required.Growth Analysis — SimulationModeling in FloridaFigure 2.Actual dataHypothetical vs actual pod loadingin Sellie peanuts grown in Florida in1979.Partitioning is determined from growthanalysis measurements from the formula:where PGR is the pod growth rate fitted to thelinear portion of the pod dry weight curve, PCFis the pod composition adjustment factor andCGR is the crop growth rate from the linearportion of the vegetative dry weight curvebefore podding begins. Partitioning is the divisionof daily assimilates between reproductiveand vegetative plant parts. Partitioning shouldnot be confused with harvest index which is astatic end-of-season computation, inadequateto explain the dynamic growth process; withthe canopy senescence of legumes, harvestindex is inaccurate and useless for evaluation ofbreeding materials.The pod weight factor can be determinedfrom representative samples of mature pods.In a growth analysis simulation modelingstudy, Duncan et al. (1978) reported the resultswhich are summarized in Table 1.We found that total dry-matter productionamong the four cultivars did not change; thefour dry matter curves could be superimposed.The crop growth rates did not differ significantlyamong cultivars and 191 kg/ha per day wascomputed as the pooled cultivar mean rate.Partitioning was the major factor whichchanged among the cultivars and it brought astep-wise yield improvement. Dixie Runner, a30-year old cultivar produced 2.47 t/ha; EarlyRunner, 20 years old, produced 3.84 t/ha;Florunner, 10 years old, produced 4.64 t/ha; andEarly Bunch, the newest cultivar from theFlorida peanut breeding program, produced5.39 t/ha. Partitioning in the Florida-bred cultivarshas been increased from 40% thirty yearsago to 98% in the newest cultivar. However, nofurther increases are possible through increasedpartitioning since the upper limit hasbeen reached in the Early Bunch cultivar.Growth Analysis — SimulationModeling in MalawiThis year in Malawi we have just completed asimilar growth analysis experiment to determinethe partitioning coefficients for threewidely grown Malawi cultivars compared toFlorunner. This should aid plant breeders ingauging how much improvement is possible inthe Malawi cultivars.Mani Pintar is a very old, high-yielding introductioninto the United States from Bolivia. Thevariety was later sent to Malawi. For ManiPintar, the VDW regression produced a crop127

Table 1. Crap growth rates, pod growth ratae, and partitioning for four paanut cultlvars grown atGainesville, Florida In 1976.Crop growth rate Pod growth rate Partitioning YieldCultivar (kg/ha per day) (kg/ha per day) (%) (kg/ha)Dixie Runner 189 + 22 40.5 + 1.6 40.5 2472Early Runner 185 ± 20 74.1 + 6.0 75.7 3843Florunner 212 ± 15 95.0 ± 4.2 84.7 4642Early Bunch 191 ± 20 98.7 + 6.0 97.8 5378growth rate of 13.4 g/m 2 per day (Fig. 3) ThePDW regression was 6.6 g/m 2 per day and apartitioning coefficient of 0.81 was obtained.The dashed line represents the adjusted assimilateflow to pods. Mani Pintar produces highyields largely because of high partitioning ofassimilates to pods. It is not surprising thatMani Pintar has been in the parentage of severalhigh-yielding cultivars such as Makula Red,Apollo, and RG-1.Chalimbana (Fig. 4) had a crop growth rate of14.4 and a pod growth rate of 5.0 g/m 2 per day,which produced a partitioning coefficient of0.57. Plant breeders should be able to achieveconsiderable yield improvement in this cultivar.RG-1 (Fig. 5) had a crop growth rate of 12.3and a pod growth rate of 6.3 g/m 2 per day,which produced a partitioning coefficient of0.84, similar to Mani Pintar which was used inbreeding the RG-1 cultivar.Florunner (Fig. 6) was used as a comparisoncultivar to determine if the partitioningcoefficient differed between the environmentsin Florida and Malawi. Florunner had a cropgrowth rate of 12.3 and a pod growth rateof 5.7 g/m 2 per day which produced a partitioningcoefficient of 0.76, somewhat lower than0.85 produced in Florida.However, both the crop growth rates and thepod growth rates were lower in the Malawiexperiment than in Florida. In Malawi the cropgrowth rate was 69% and the pod growth was60% of that in Florida. In Malawi, some factorrestricted photosynthesis; quite likely the factorwas a deficiency of magnesium. This restrictionnecessitated using a PNE factor less than 1.0 inFigure 3. Vegetative dry weight, pod dryweight, and partitioning of assimilatesfor Mani Pintar grown inMalawi in 1979-80.Figure 4. Vegetative dry weight, pod dryweight, and partitioning of assimilatesfor Chalimbana grown inMalawi in 1979-80.128

Figure 5. Vegetative dry weight, pod dryweight, and partitioning of assimilatesfor RG-1 grown in Malawi in1979-80.partially alleviated the magnesium deficiency,and in our model the photosynthetic rate (PNE)after pegging had to be increased to85% of thatfor Florida (1.0) in order to produce vegetativeand pod dry weights which would match theMalawi growth analysis data.We believe this is an example of the value ofsimulation modeling. We want to know if thelow magnesium affected the photosyntheticrates and if the low crop and pod growth ratesaffected partitioning. We will be testing this inan experiment during the 1980-81 growingseason.A comparison of the actual growth analysis ofMani Pintar data with the data from the PNUTSmodel (Fig. 7) showed very high correlationbetween vegetative dry weights for the linearportion of the curve until podding began —0.998. For the linear portion of the pod dryweight curve the correlation was 0.992. Thus,the model is excellent for predictingdry weightsover these periods.Figure 6. Vegetative dry weight, pod dryweight, and partitioning of assimilatesfor Florunner grown in Malawiin 1979-80.Figure 7.Actual data vs the simulation modelfor Mani Pintar grown in Malawiduring 1979-80.the model. Soil tests showed very low magnesiumand calcium levels and a low pH, andsince no dolomitic limestone was available inMalawi, calcic limestone was applied at plantingand did not alleviate the magnesium deficiency.The appi cation of gypsum at peggingThe discrepancies between actual vegetativedry weight and the model's prediction afterpodding begins are due to the loss of leavesfrom disease and senescence. We believe thatthe difference between the model and the actualdata is a reasonabie estimate of leaf loss.129

Temperature vs Pod NumberAnother experiment which we conducted inFlorida is summarized in Table 2 (Dreyer et al.1980). This experiment was conducted to testour hypothesis that the number of pods establishedper plant should be inversely proportionalto the growth rates of the individual podsPeanuts were chosen as the test plant becausewe could vary the pod growth rates in the fieldby cooling or warming the small soil volumeoccupied by the growing pods.As predicted by the hypothesis, slowergrowth rates per pod, obtained by cooling thepod-zone soil, increased the total number ofpods established per plant. Warming the podzonedid not increase the pod growth rates andcaused no reduction in the number of pods.When harvest was delayed until maturity foreach treatment, average single pod weightswere the same for each soil temperature. Thus,slower pod growth rates produced largeryields,but a longer filling period was required.We feel that the particular method used toslow pod growth rate is incidental. The sameresults could have been attained by breedingfor slower growing pods or by chemical treatmentsto achieve the same end, as long as themethod used did not reduce mature podweight. Presumably, an increase in the finalpod weight without affecting the individual podgrowth rate would have affected a similar enhancementof yield although maturity wouldalso have been delayed. The mean pod growthrate was 8.4 g/m 2 per day across all temperaturetreatments. The higher yield for the lowest soiltemperature treatment resulted from the longerpod filling period required.Physiological Specificationsfor High YieldsOur work on the physiological basis for yieldimprovement in peanuts clearly shows thereare four aspects that promote high yields:(1) a rapid expansion phenophase, (2) a shortpodding phenophase, (3) a long fillingphenophase, and (4) a high partitioning of assimilatesto pods. Our work shows that thesefour are the physiological aspects which, underoptimum growing conditions, are most importantin promoting high peanut yields. Under SAT conditionswith restricted moisture and fertility,physiological specifications such as droughtand low fertility tolerance must be considered.In addition to these physiological specifications,there are of course the usual diseaseresistance, quality, and other factors for thebreeder to consider.A rapid expansion phenophase, thetime fromplanting to full ground cover, promotes betterweed control. When the length of the growingseason is fixed by temperature or moisture, arapid expansion phase saves time which can beused to lengthen the pod filling period therebyproducing higher yields. Flowering and poddingshould begin before full ground cover isreached. This early flowering and podding alsosaves time and helps shorten the poddingperiod.A short podding phenophase is a desirablephysiological attribute. Pods should be addedrapidly until a full pod load is set. However, if allpods were set in a single day, and if that daywere cloudy or in a drought-stress period, lessphotosynthate would be available for the podsand the plant would respond by setting fewerTable 2. Fruiting tone soil temperature, pod number, and pod growth rate for Sellle peanuts grownin Florida, USA, 1979.Soil temp. Pods harvested Single pod growth rate Mean pod growth rateCO (no./m 2 ) (mg/pod per day) (g/m 2 per day)23 1060 7.9 8.427 845 9.9 8.430 840 10.0 8.434 830 10.1 8.437 790 10.6 8.4130

pods and the final yield would be lower.Peanuts then would be more like corn which hasa very short critical period at silking when grainnumbers are irreversibly determined. Forpeanuts, the final few days of podding arecritical; however, peanuts, unlike corn, can resumepodding when conditions become morefavorable. Even under optimum conditions,peanuts have an excess of flowers and pegs, butthis does not mean an "extra" yield potential.Pod load is adjusted to the photosynthate flowto the pods during the last few days of podloading, and under optimum conditions thisload is set by solar radiation and partitioning.A long filling phenophase is anotherphysiological attribute which contributes tohigh yield in peanuts. We feel that a longerfilling period can be achieved in two ways: by alower individual pod filling rate, or by a largerseed size with the same pod filling rate. Thecombination of a lower individual pod fillingrate and a larger seed size would promote evenhigher yields, but the penalty would be a muchdelayed maturity.A high partitioning of assimilates to podspromotes high yields in peanuts. The stepwiseyield improvement in the Florida breedingprogram was largely achieved by increasedpartitioning. The latest cultivar Early Bunchpartitions all of its assimilates to pods, andduring late pod filling, the vegetative canopyshows stress effects of this assimilate drain.Selection Criteriafor the Plant BreederHow can the plant breeder utilize this physiologicalinforamtion? Some examples of selectioncriteria for the plant breed er for rapid expansionwould be: lack of dormancy, rapid germination,seedling vigor, and rapid spread.A short podding phase is more difficult toselect for, especially using individual widespacedplants. In solid stands the date at thebeginning of flowering when the first 10% of theplants are blooming, and before flowering terminatesthe date at which the last 10% of theplants remain in flower, should be recorded. Thedifference between these two dates in days canbe used as a podding index. The lower this index,the shorter the podding period.Perhaps the best index for length of fillingperiod is the days from the final 10% cut-off offlowering to maturity. The longer this period,the longer the filling period. Later maturityalone is not specific enough. What the breederneeds is an index of the actual days spent infilling. In the United States, hybrid corn breederswere at this stage 30 years ago. I recentlyasked an eminent U.S. corn breeder howbreeders had achieved higher yields during thelast 30 years. He replied that they have moreeffectively utilized the available growing seasonby selecting for earlier silking without changingthe days to maturity, which is set by frosts in thespring and fall. In physiological terms, thismeans lengthening the filling period. Forpeanuts, the breeding objective from aphysiological standpoint should be to select thenew cultivar for the expected length of theparticular growing season to which it will beadapted (which is generally set either by moistureor temperature) and to use the largestpossible proportion of the available growingseason for pod filling. This is fine-tuning of acultivar. It is difficult to select for high partitioning.Selections for yield can be made, but yieldselection often may not be specific for partitioning.Perhaps the best approach for the breederis to select the parents in crossing programs forhigh partitioning. In many SAT countries, rapidyield improvement can be made by selecting forhigher partitioning; however, selection for veryhigh partitioning can lead to reduced yieldsunder conditions of environmental stress.Plant breeders can make rapid progress byselecting for improved partitioning with cultivarswhich have a low partitioning coefficientalthough caution should be exercised for adverseconditions. Selecting for rapid expansion,short podding, or long filling periods will bemuch more difficult, time consuming, and willtake considerable innovative ingenuity. There islittle evidence in peanuts or other crop plantsthat the basic photosynthetic process can beimproved; selecting for phtosynthetic efficiencyis unlikely to be successful.ReferencesDUNCAN, W. G., MCCLOUD, D. E., MCGRAW, R. L, andBOOTE, K. J. 1978. Physiological aspects of peanutyield improvement. Crop Science 18: 1015-1020.131

DREYER, J., DUNCAN, W. G., and MCCLOUD, D. E. 1980.Fruit temperature, growth rates, and yield ofpeanuts. Submitted for publication to Crop Science.INGRAM, K. T., MCCLOUD, D. E., CAMPBELL, I. S., DUNCAN,W. G., MCGRAW, Ft. L, and SIBALE. P. K. 1980. Aneducational model to simulate peanut crop growthand development in a hand-held mini computer.Submitted for publication to Journal of AgronomicEducation.132

Groundnut in Intercropping SystemsM. S. Reddy, C. N. Floyd and R. W. Willey*In the developing world, groundnuts are commonlygrown in intercropping systems, especiallyby small farmers who use traditionalcombinations often involving up to 5-6 crops.Detailed statistics of farming practice aredifficult to obtain, but it has been estimated that95% of the groundnuts in Nigeria and 56% inUganda are grown as mixtures with other crops(Okigbo and Greenland 1976). In the NorthernGuinea Savanna Zone of Nigeria, Kassam(1976) reported that only about 16% of the totalarea under groundnut was in sole croppingwhile about 70% was in 2-4 crop mixtures. Underplantingtree crops such as coconut, oilpalm,and rubber trees with groundnuts in the earlyyears of the plantation is also a common featurein S.E. Asia (Hardwood and Price 1976) andIndia (Aiyer 1949).This paper considers the intercropping ofgroundnut only with other annual crops; itdeals mainly with the cereal intercrops (millet,maize, and sorghum), which are by far the mostimportant intercrops grown with groundnut. Italso considers briefly a further important group— the long-season annuals such as pigeonpea,cotton, castor, and cassava.Intercropping of Groundnutwith CerealsGroundnut/Pearl Millet IntercroppingThe groundnut/millet combination has beenchosen for special emphasis at ICRISAT becauseit involves two ICRISAT mandate cropsand the combination is an especially importantone on the lighter soils of the semi-arid tropics,notably in West Africa and India.A series of crop physiological experimentshas been carried out since 1978 in four different* Agronomist, Research Intern, and PrincipalAgronomist, respectively. Cropping Systems,ICRISAT.seasons at ICRISAT Center, to study the growthpatterns and the resource use in this combinationto determine how yield advantages areachieved. The first experiment, conducted duringthe rainy season of 1978, compared solecrops with a single intercrop treatment of 1 rowmillet: 3 rows groundnut. Results have beenpresented in detail elsewhere (Reddy and Willey1980a) so they are only briefly summarizedhere.Growth patterns are plotted in Figure 1. Solemillet showed a very rapid rate of growth,achieving 8134 kg/ha of dry matter in 85 days(Fig. 1b). Sole groundnut growth rate wassomewhat slower, and this crop achieved 4938kg/ha of dry matter in 105 days (Fig. 1a). Drymatter yield of each crop in intercropping isgiven in comparison with an expected yield, thisbeing the yield that would be achieved if thecrop experienced the same degree of competitionin intercropping as in sole cropping.Groundnut growth very closely followed theexpected dry matter yield of 75% of its sole cropyield, whilst millet produced approximatelytwice its expected dry matter yield of 25% of itssole crop yield. In effect, this means thatgroundnut produced about the same yield perplant in intercropping as in sole cropping, whilethe much more dominant millet approximatelydoubled its yield per plant in intercropping.The combined dry matter yield in intercroppingis given in comparison with the yield expected,if there was no yield advantage (or disadvantage)of intercropping, i.e.,of the LER = 1(LER = Land Equivalent Ratio, or the relativeland area required as sole crops to produce theyields achieved in intercropping). Figure 1cshows that with time there was an increasingdry matter yield advantage for intercropping; atfinal harvest the actual LER was 1.29, i.e., anadvantage of 29% for intercropping. Grain andpod yields closely followed this pattern and actualLERs were 0.71 for groundnut and 0.55 formillet, giving a total LER of 1.26, or an overallyield advantage of 26% for intercropping.133

Figure 1. Sole crop yields and actual and expected intercrop yields of groundnut and millet.Resource use was of particular interest in thiscombination. Considering moisture use first,the amounts of water transpired through thesole crops and the intercrop are presented inTable 1. (The amount for the intercrop could notbe apportioned between the crops.) For thecombined intercrop, an expected moisture usewas also estimated by calculating for eachcomponent the amount of moisture whichwould have been used if dry matter had beenproduced at the same efficiency as the respectivesole crops. It can beseenthatthiscaiculatedmoisture use was very similar to the actualmoisture use, thus there was no evidence thatintercropping was able to produce more drymatter per unit of water transpired through thecrop.Light interception patterns are presented inFigure 2. Sole millet showed a particularly rapiddevelopment of light interception, but the solegroundnut was rather slower. The combinedintercrop was intermediate to the two solecrops in the early stages, but by about 60 days itwas similar to both the sole crops; thereafter itdeclined because of senescence and removal ofthe millet and then senescence of thegroundnut. Light use by the individual componentsin intercropping could not be distinguished.But the estimated amount of lightenergy which would have been needed to producethe intercrop yields, assuming the samelevel of efficiency as the sole crops, was appreciablyhigher than the measured amount intercepted(Table 1). Calculation showed that theintercrop appeared to use light with 28% greaterefficiency. This agrees very closely with theLERs given earlier, suggesting that the yield advantagesof intercropping were due very largelyto more efficient use of light. In fact, during theperiod of maximum leaf area, the intercropsupported a leaf area that was approximately30% greater than the sole crops. Thusthe greater efficiency of light use may at leastpartly have been because light was more evenlydistributed over more leaves. It could also havebeen partly due to the combination of a C 4 cropin the upper canopy layers and a C 3 one in thelower canopy layers.An important feature of this first experiment,however, was that it was conducted at a relativelyhigh level of fertilization (80 kg N/ha and50 kg P20s/ha) and the season turned out to beparticularly wet with rainfall well above average.Thus it was considered that a major reasonwhy the higher intercropping yields appearedto be especially associated with increased efficiencyof light use could have been becausenutrients and water were not limiting. A mainobjective of subsequent experiments was tore-examine the relative importance of this lightfactor in situations where the below-ground resourceswere more limiting. Results have been134

Table 1.Efficiency of resource use in pearl millet/groundnut intercropping.MilletGroundnutWater useSole croppingDry matter (kg/ha) 8134.00 4938.00Water used (transpiration, cm) 15.86 19.63Water-use efficiency (kg/cm) 513.00 252.00IntercroppingDry matter (kg/ha) 4129.00 3821.00Water used at sole-crop 8.05 15.19efficiencies (cm) 23.24Expected water-use efficiency (kg/ha) 342.00Actual water used (cm) 22.79Actual water-use efficiency 349.00Light-energy conversionSole croppingDry matter (kg/ha) 8134.00 4938.00Total light intercepted (kcals/cm 2 } 14.26 19.25Efficiency of conversion (mg/kcal) 5.70 2.57IntercroppingDry matter (kg/ha) 4129.00 3821.00Energy required at sole crop 7.24 14.90conversion rate (kcals/cm 2 ) 22.14Expected conversion efficiency (mg/kcal) 3.59Actual interception (kcals/cm 2 ) 17.25Actual conversion rate (mg/kcal) 4.60Figure 2.Light interception by sole crops andan intercrop of pearl millet andgroundnut.presented in detail elsewhere (Reddy andWilley (1980b), so again they are only brieflysummarized here.During the postrainy season of 1978, an experimentwas conducted to study the effect ofno-stress and stress moisture regimes (Table2).The pattern of intercrop results in no-stress wassimilar to that reported in the previous experimentand the reproductive yield advantage was25%. Under stress the reproductive yield advantagewas rather higher at 29%. The efficiencywith which light energy was convertedinto dry matter was calculated as in the previousexperiment; in no-stress the intercrop was 2 1 %more efficient than expected, while in stress itwas only 7% more efficient. Thus the resultssuggest that when moisture is more limiting,the efficiency of light use may be a less importantfactor in determining the yield advantage ofthis particular crop combination.During the rainy season of 1979, an experimentwas carried out to study the effect of two135

Table 2. Grain or pod yields and land equivalent ratios in pearl millet/groundnut Intercroppingunder two different moisture regimes (1978 postralny season).MilletGroundnutgrain yieldsMilletpod yieldsGroundnut TotalTreatments (kg/ha) LER (kg/ha) LER LERNO STRESS(Irrigated every10 days)Sole crop 2674 - 2441 - -1 : 3 Intercrop 1220 0.46 1928 0.70 1.25STRESS(Irrigated every20 days)Sole crop 2114 - 2040 - -1 : 3 Intercrop 937 0.44 1734 0.85 1.29LSD (0.05) withina moisture regime 109 146 0.09LSD (0.05) acrossmoisture regimes 133 217 0.08CV (%) Main plots 3.26 4.95 2.57CV (%) Split plots 3.60 4.03 4.38different nitrogen levels on the millet (Table 3).The pattern of results was again similar to theprevious experiments in that at a high level ofnitrogen (Nso) the reproductive yield advantagewas 2 1 % but this increased under stress (nil N)to 32%. Dry matter yield advantages were evenhigher (Table 3). The efficiency of light energyconversion of the intercrop compared with thesole crops was calculated as in the earlier experiments.At Nso, the intercrop was only 14% moreefficient, which was a rather smaller effect thanin the previous experiments. At nil N, however,the improved light use efficiency of the intercropwas even higher, being 2 1 % . At first, thiseffect at nil N is rather surprising, as it seems tocontradict the earlier suggestion from the moistureregime experiment that when a factor otherthan light is more limiting, the efficiency of lightuse is less important. But the results may simplyindicate some essential differences betweenthe moisture stress and nitrogen stress situationswhich were created. One notable differenceof course was that the moisture stressappiied to both component crops, whereas thenitrogen differences applied only to millet Currentstudies are examining situations wherephosphate levels are also varied so that nutritionalstress also applies to the groundnut.Groundnut/Maize IntercroppingGroundnut is very commonly intercropped withmaize in Southeast Asia and Africa. Mutsaers(1978) reported that in western Cameroon, thefarmer grows groundnut as the main crop withmaize interplanted at a fairly low density. Experimentscarried out during three seasons in theYaound'e area, Cameroon, to evaluate groundnut/maizemixtures, gaveyield advantages overpure stands ranging from 6-16%. Evans (1960)obtained yield advantages ranging from 9-54%from five different experiments conducted attwo different locations in Tanzania during 1957and 1958. In Ghana, Azab (1968) studiedgroundnut/maize intercropping by varying thesowing time of each crop. He observed that themean yield of groundnuts was significantlyhigher when sown 4 weeks earlier thanmaize. The traditional practice of sowing bothcrops at the same time gave an intermediateyield. Koli (1975) reported that the yields ofgroundnuts in mixed cropping treatments were136

Table 3. Grain or pod yields and land equivalent ratios in pearl millet/groundnut Intercroppingunder two different levels of nitrogen applied to the millet (1979 rainy season).Pearl milletGroundnutgrain yields Pearl pod yieldsmilletGroundnut TotalTreatments (kg/ha) LER (kg/ha) LER LERSole groundnut - - 2998 - -Sole pearl millet(0 kg N/ha) 1968 - - -Sole pearl millet(80 kg N/ha) 2872 - - - -1:3 Intercrop(0 kg N/ha) 1063 0.54 2345 0.78 1.321:3 Intercrop(80 kg N/ha) 1436 0.50 2131 0.71 1.21LSD (0.05) 233 117 0.12CV(%) 8 4 6.71one-third to one-half the yields obtained fromsole crops, but yield of maize was not reducedto the same extent. The general observation inall reports on the maize/groundnut combinationis that groundnut yield is readily depressedby competition from the maize.A groundnut/maize experiment was conductedon an Alfisol at ICRISAT in the rainy seasonof 1978 to study whether there was anybeneficial transfer of fixed nitrogen from thelegume to the cereal. Treatments consisted ofmaize at 0, 50, 100, and 150 kg/ha of appliednitrogen, and with and without a groundnut intercrop.With no applied nitrogen, maize growthwas very poor and obviously nitrogen deficient,and there was no visual evidence of growthbeing any better if the groundnut intercrop werepresent. This observation was supportedby maize grain yields which were unaffectedby the groundnut at any level of nitrogen.The relative yield advantage of intercroppingcompared with sole cropping was44% at zero nitrogen level but this decreasedwith increase in applied nitrogen and it was zeroat the highest nitrogen level (Rao et al. 1979).Since there was no evidence that these differencesin yield advantage could be due to differencesin nitrogen transfer, it is possible thatthey occurred because intercropping was moreefficient in using soil nitrogen, an effect that wasmore evident at lower levels of applied nitrogen.This finding agrees with the general trendobserved in the groundnut/millet experimentreferred to above (Table 3) and it has importantimplications in practice because it suggests thatintercropping may be more advantageous inlow fertility situations.This groundnut/maize experiment was followedby a post rainy season crop of sorghum tostudy the residual effect of sole versus intercroppedgroundnut. The results showed that ifno nitrogen were applied to the groundnut/maize intercrop, there was a beneficial residualeffect on the following sorghum. Where nitrogenwas applied to the maize, however, thegroundnut growth was suppressed and the residualbenefit rapidly diminished (Rao et al.1979).Groundnut/Sorghum IntercroppingIn India and Africa, groundnut is very commonlyintercropped with sorghum. Some reportshave emphasized that significant yield reductionsof groundnuts have been obtainedwhen they have been intercropped with sorghum.John et al. (1943) reported that sorghumdepressed the yield of groundnut by about 50%and Bodade(1964) obtained reductions of 52%.But despite reductions in groundnut yields,there are many reports of overall benefits whenthe yields of both crops are considered.137

Bodade (1964) reported that mixed croppingof sorghum and groundnut gave higher yieldsthan sole cropping and two rows of sorghumwith eight rows of groundnut was one of thebest treatments. Lingegouda et al. (1972) reportedthat three rows of groundnut and onerow of sorghum was more profitable (Rs. 3918/-per ha) than pure sorghum (Rs. 3123/-) or puregroundnut (Rs. 2672/-). A positive benefit wasshown in almost all experimental combinationsof groundnuts with sorghum in East Africa(Evans 1960). Experiments conducted atICRISAT with this combination have given yieldadvantages as high as 38% (Rao and Willey1980) while Tarhalkar and Rao (1979) havereported yield advantages up to 57%.Groundnut Genotypesfor Groundnut/CerealIntercroppingater in intercropping because of possible interactionswith the associated cereal crops. Ithas also been emphasized that for crops growingwith a more dominant associated crop,there may be particular need for identificationand selection of genotypes within the actualintercrop situation because genotype performancein intercropping may not be very closelyrelated to genotype performance in sole cropping(Willey 1979).At ICRISAT, studies on the identification ofgroundnut genotypes for intercropping withpearl millet have been carried out since 1977. Todate, results are only available for a relativelyfew genotypes of groundnut, and these havebeen examined in combination with only a fewpearl millet genotypes (Table 4). All studieswere in simple replacement series treatmentsof 3 groundnut rows: 1 pearl millet row. Resultshave indicated that with increasing groundnutmaturity, and the associated change frombunch to runner habit, the groundnut contributionin intercropping (i.e. groundnut LER) tendsto increase (Table 4). This is probably becauseof the increasing time for compensation of thegroundnut after cereal harvest.However, this increasing groundnut con-Table 4.The affact of groundnut ganotypa and ganaral typa of millat ganotypa on groundnut LERand total LER in groundnut /pearl millat Intarcropping.Groundnut Genotypes1. Chico 2. MH2 3. TMV24. R33-1 5. MK374 6. M-13Spanish ValenciaSpanish Virginia Virginia Virginia Meansbunch dwarf bunch semi- semi- runner (GenotypesPearl millet genotypes 85 days 95 days 100 days spreading spreading 130-140 3-6)110 days 125 days daysGAM73/GAM75 g nut LER 0.51* 0.63 d 0.72 d 0.80 c 0.81 d 0.74(dwarf, late) Total LER 1.13 1.25 1.22 1.27 1.33 1.27BK560/WC-C75 g nut LER 0.48 s 0.48 a 0.61 e 0.63 6 0.80 c 0.80 e 0.71(medium/medium) Total LER 1.03 1.17 1.27 1.23 1.25 1.39 1.29PHB-14/IVSAX75 g nut LER 0.67* 0.70* 0.68* 0.74* 0.70(tall/medium) Total LER 1.09 1.18 1.01 1.28 1.14Ex-Bornu g nut LER 0.90* 0.90* 0.80 a 0.90* 0.88(all, late) Total LER 1.25 1.22 1.15 1.28 1.23Means g nut LER 0.48 0.50 0.70 0.74 0.77 0.81Total LER 1.03 1.15 1.22 1.21 1.17 1.32As in sole cropping, it seems likely thatgroundnut performance in intercropping couldbe improved by identification of suitablegenotypes. Indeed it can be argued that the potentialfor genotype improvement could be grea.Mean of 1 trial b. Maan of 2 trials c Mean of 3 trials d. Moan of 4 trials a. Mean of 5 trials138

tribution is not so clearly reflected in increasingyield advantages for the combined effect ofboth crops (i.e. total LER); although the latestmaturing groundnut M-13 (130-140 days) wasassociated with the highest mean value for totalLER, there were no real differences in total LERobservable between the three genotypes TMV2(100 days), Robut33-1 (110 days), and MK-374(125 days). There was also little difference ingroundnut or total LER for the different milletgenotypes, though the range of milletgenotypes was admittedly limited.In these initial stages of identification, simultaneousscreening of genotypes of both cropswas carried out because there appeared to bescope for selecting more suitable genotypes ofboth crops. No marked interaction betweengenotypes of the two crops has been observedso work is now concentrating on examining alarger number of genotypes of each cropagainst a standard genotype of the other crop.With the groundnuts, a more detailed study isalso being carried outtodeterminethe extenttowhich the better intercrop performance of thelonger maturing genotypes is due to greatertime for compensation after cereal harvest or tosome other characters which allow bettergrowth and production in the dominated intercropsituation. In the summer season of 1980,groundnut genotypes were grown with a standardcereal (Sorghum CSH-8); the duration ofcereal competition was examined by removingthesorghum at differenttimes, and the intensityof cereal competition was examined by meansof a treatment in which alternate pairs of sorghumleaves were removed. First resultssuggest that increased groundnut contributionwith reduced cereal duration was of the sameorder for all groundnut genotypes and bothlevels of competition. Differences in groundnutperformance were small at a given cereal duration,though there was a tendency for the bunchtypes to do less well than the late runner types.Groundnut Intercropped withLong Season Annual CropsNo growth studies have been reported for combinationsof groundnuts with any of the longseason annuals. However, it is evident from thegeneral growth patterns of the crops that considerabletemporal complementarity of growthoccurs. The groundnuts can give reasonablyefficient use of resources during the earlyperiod when the long season annuals are slowto establish; after groundnut harvest, the longseason annuals are able to make use of laterresources, especially of the residual soil moisture.Groundnut/Pigeonpea IntercroppingThis combination is particularly prevalent onred soils of the southern States of India. Acommon practice here is that if rains commenceat the normal time a groundnut/sorghum orgroundnut/millet intercrop is grown, but if rainsare delayed groundnut/pigeonpea is grown.Pigeonpea rows are usually wide-spaced up to5 m apart with up to 8-10 groundnut rows inbetween. This traditional practice helps to obtainhigh yields of the groundnut cash crop butthe overall advantage of intercropping may notbe high because pigeonpea is too sparsely distributedto make efficient use of late seasonresources and produce a worthwhile yield contribution.Most studies have examined this predominantlygroundnut situation.John et al. (1943) reported from a 3-year studythat groundnut/pigeonpea in 8:1 proportionwas 43% more profitable than sole groundnut.Similar results were reported from studies atTindivanam over a 7-year period during 1942-49 (Seshadri et al. 1956). Veeraswamy et al.(1974) and Appadurai et al. (1974) showed thatthe arrangement of 6 groundnut: 1 pigeonpeawas more economical than 8 : 1 ; groundnutgave 99% of its sole crop yield and pigeonpea37% of its sole crop yield, totaling an advantageof 36%.At the other extreme, an alternate row arrangementat ICRISAT gave an LER of 1.53comprising 95% pigeonpea and 58% groundnut(Rao and Willey 1980). This may not beideal economically because of the reducedgroundnut contribution, but it illustrates thathigher yield advantages can be obtained withhigher proportions of pigeonpea.A good compromise situation is indicated bysome studies on five Alfisol locations within IC-RISAT in 1979-80. Pigeonpea was grown in 135cm rows with five very close-spaced rows ofgroundnut between. The population of eachcrop was equivalent to its sole crop optimum.Intercrop yields averaged 82% of groundnut139

and 85% of pigeonpeas, i.e. 67% total advantage.Groundnut/Cotton IntercroppingJoshi and Joshi (1965) reported that a combinationof 2-3 rows of groundnut between cottonrows spaced 6 feet apart gave significantlyhigher monetary returns compared to eithersole crop. Varma and Kanke (1969) reported thatgrowing cotton with groundnut was much moreremunerative than growing it alone; yields ofgroundnuts were additional to the cotton yieldsusually obtained. Similar intercropping ofcotton and groundnut has been recommendedfor the northern districts of Madras by NarayanReddy (1961). In the Sudan, Anthony and Wilmott(1957) also found higher yields fromgroundnut and cotton intercropped together.Groundnut/Castor IntercroppingReddy et al. (1965) reported that growing castormixed with groundnut was better than raising apure crop of castor, and monetary returns were61.9% higher than pure castor. They also reportedthat the yield of castor was more when itwas grown mixed with groundnut compared tocastor grown mixed with greengram, cowpea,Setaria, millet or sorghum. In East Africa, Evansand Sreedharan (1962) showed that there was aclear increase in production when castorbeanand groundnuts were planted together comparedto sole cropping. Tarhalkar and Rao(1975) reported that intercropping of castor/groundnut gave monetary returns up to Rs 4394per hectare compared with Rs 3317 per hectareobtained from a pure castor crop.Groundnut/Cassava IntercroppingIntroducing an additional crop like groundnutbetween the traditionally wide-spaced cassavaplantings would increase the production efficiencyof cassava-planted land as well as conservingsoil moisture and fertility. An experimentconducted at Khon Kaen University,Thailand in 1977, produced higher yields of cassava(26 756 kg/ha) when intercropped withgroundnuts compared to sole crop of cassava(24 538 kg/ha). The experiment indicated thatpresumably intercropped groundnut increasedthe yield of cassava by supplying additional nitrogenfrom nitrogen fixation. This groundnut/cassavacombination gave around doublethe net income compared with the sole cassavaplanting. Contrary to this, the Department ofAgriculture, Tanganyika (1959) reported thatwhen early sown groundnuts were intercroppedwith late-planted cassava, the yield ofgroundnuts was not seriously affected, but theyields of cassava were reduced to less thanone-fifth of the sole crop. Potti and Thomas(1978) reported that trials conducted in the farmers'fields in Kerala, India gave an average of1263 kg/ha of groundnut in addition to the cassavayield.ConclusionsThere is good evidence that groundnut/cerealintercropping can give worthwhile yield advantagesover sole cropping. The ICRISAT studiessuggest that these advantages can be due partlyto more efficient use of light, but further researchis needed to determine the importanceof this light factor when below-ground resourcesare limiting. The more rapid earlygrowth of the cereals, and the later maturity ofgroundnut compared with the early cereals,may also be an important factor giving somecomplementarity between the crops and allowingbetter use of resources.Other ICRISAT studies have shown that thelater maturing, semi-spreading or runner typesof groundnut have given the highest groundnutyields in intercropping, but this has not alwaysresulted in improved yield benefits from thewhole system.Although there has been little detailed workon the intercropping of groundnuts with thelong season annuals, pigeonpea, cotton, castor,and cassava, there is good agronomic evidencethat these systems can give very substantialyield advantages. The general growth patternsof these crops suggest that the main factor responsiblefor these advantages is that the use ofearly resources by the groundnut complementsthe use of late resources by the longer seasoncrops.ReferencesAIYER, A. K. Y. N. 1949. Mixed cropping in India. IndianJournal of Agricultural Science 19: 439-543.140

ANTHONY, K. R. M., and WILLIMOTT, S. G. 1957. Cottoninterplanting experiments in the South-West Sudan.Empire Journal of Experimental Agriculture25: 29-36.APPADURAI, R., and SELVARAJ, K. V. 1974. A note ongroundnut — redgram mixture in lower BhawaniProject area. Madras Agricultural Journal61: 803-804.AZAB, Y. E. A. 1968. Pages 5-8 in Applied agronomicresearch on field food crops in Northern Ghana(FAO. No. TA 2596).DEPARTMENT OF AGRICULTURE, TANGANYIKA. 1959. Intercropping.Report of the Department of Agriculture,Tanganyika. 11pp.EVANS, A. C. 1960. Studies of intercropping. I. Maize orsorghum with groundnuts. East African Agriculturaland Forestry Journal 26: 1-10.EVANS, A. C, and SREEDHARAN, A. 1962. Studies ofintercropping. II. Castorbeans with groundnuts orsoyabean. East African Agricultural and ForestryJournal 28(1): 7-8.HARDWOOD, R. R., and PRICE, E. C. 1976. Multiple croppingin tropical Asia. Pages 11-40 in Multiple cropping.Society of Agronomy, Special Publication No.27, Madison, Wisconsin, USA.JOSHI, S. N., and JOSHI, H. V. 1965. Mixed cropping ofgroundnut/cotton under irrigated conditions inSaurashtra. Indian Oilseeds Journal 9(4): 244-248.JOHN, C. M., SESHADRI, C. R., and BHAVANI SHANKERRAO, M. 1943. Mixed cropping of groundnut. MadrasAgricultural Journal 31: 191-200.KASSAM,A. H. 1976.Pages41-48 in Crops of the WestAfrican Semi-Arid Tropics. ICRISAT, Hyderabad,India.KHON KAEN UNIVERSITY/FORD CROPPING SYSTEMS PROJECTANNUAL REPORT. 1977. Pages 25-39 in Intercropping ofcassava with field crops.Kou, S. E. 1975. Pure cropping and mixed cropping ofmaize and groundnuts in Ghana. Ghana Journal ofAgricultural Science 8: 23-30.LING EGO woA, B. K„ SHANTAVEERABADRAIAH, S. M., IN-AMDAR, S. S., PRITHVIRAJ, and KRISHNAMURTHY, K.1972. Studies on mixed cropping of groundnut hybridand hybrid sorghum. Indian Journal of Agronomy17(1): 27-29.MUTSAERS, J. A. 1978. Mixed cropping experimentswith maize and groundnuts. Netherlands Journal ofAgricultural Science 26: 344-353.NARAYAN REDDY, M. R. 1961. Economics of groundnutand cotton mixtures versus pure groundnut crop inthe northern track of Andhra Pradesh. Andhra AgriculturalJournal 8: 66.OKIGBO, B. N., and GREENLAND, D. J. 1976. Intercroppingsystems in tropical Africa. Pages 66-101 inMultiple cropping. American Society of AgronomySpecial publication No. 27, Madison, Wisconsin,USA.PoTTI, V. S. S., and THOMAS, A. 1.1978. Groundnut as acompanion crop in tapioca. In Proceedings of thenational symposium on intercropping of pulsecrops, IARI, New Delhi, July 17-19.RAO, M. R., AHMED, S., GUNASENA, H. P. M„ and ALCAN-TARA, A. P. 1979. Multi-locational evaluation of productivityand stability of some cereal-legume intercroppingsystems: A review of inputs trial III. InProceedings of the Final Inputs Review Meeting,held at Honolulu, Hawaii, Aug 20-24.RAO, M. R., and WILLEY, R. W. 1980. Preliminarystudies of intercropping combinations based onpigeonpea or sorghum. Experimental Agriculture16: 29-39.REDDY, G. P., RAO, S. C, and REDDY, R. 1965. Mixedcropping in castor. Indian Oilseeds Journal9(4): 310-316.REDDY, M. S., and WILLEY, R. W. 1980. Growth andresource use studies in an intercrop pearl millet/groundnut. Field Crops Research (In press).REDDY, M. S., and WILLEY, R. W. 1980. The relativeimportance of above and below ground resourceuse in determining yield advantages in pearl millet/groundnut intercropping. Paper presented at thesecond symposium on intercropping in semi-aridareas. Held at University of Dar-es-Salaam, Morogoro,Tanzania, Aug 4-7.SESHADRI, C. R., AIYADURAI, J. G., and SRINIVASALU, N.1956. Groundnut-mixed cropping experiment. MadrasAgricultural Journal 43: 496-504.TARHALKAR, P. P., and RAO, N. G. P. 1975. Changingconcepts and practices of cropping systems. IndianFarming, June 3-7.VARMA, M. P., and KANKE, M. S. S. 1969. Selection ofintercrops for cotton in India. Experimental Agriculture5: 223-230.141

VEERASWAMY, R., RATHNASWAMY, R„ and PALANIS-WAMY, G. A. 1974. Studies in mixed cropping of red -gram and groundnut under irrigation. Madras AgriculturalJournal 61: 801-802.WILLEY, R. W. 1979. Intercropping — Its importanceand research needs. I. Competition and yield advantagesand II. Research approaches. Field CropAbstracts 32: 2-10 and 73-81.142

Session 5 — Crop Nutrition and AgronomyDiscussionMicrobiologyJ. S. SainiIn a trial in the Punjab we found that whenwinter wheat was planted either aftergroundnuts, hybrid maize, or local maize wegot better wheat yields after the local maize.This was surprising. What explanation can beoffered?P. T. C. NambiarIt is difficult to generalize on this. One likelyexplanation is that in this instance, nitrogenwas not limiting. At ICRISAT we have obtaineda 30% yield increase in pearl millet when itfollowed groundnuts.N. D. DesaiWhen do nodules form and when does fixationcommence?P. T. C. NambiarInitiation varies from season to season. In therainy season they form as soon as 11 daysafter planting. In the postrainy season, theymay not form until 18 days after planting.Nitrogenase activity commences 20 days afterplanting in the rainy season.P. J. DartThere are large nitrogen reserves in the seedand therefore a shorter dose of nitrogen maynot be needed. Water also limits nodulationand the uptake of nitrate.D. J. NevillWe heard a lot about host and Rhizobiumstrain interactions. What about higher orderinteractions such as strain x host x environmentinteractions? In other words, does asuccessful combination of strain and hostbehave the same way in North Carolina as itdoes in India?P. T. C. NambiarWe are doing such trials but we have noresults yet.J. C. WynneWe are cooperating in these trials withICRISAT. We do not have results yet, but I wouldsuspect that the combinations would bespecific to sites. A lot would depend on thevariety and the photosynthetic activity of thevariety in the different environments.S. N. NigamIn one of the slides that showed analysis of severalcharacters, there was no significance fornodule number for the host cultivars. I wouldhave expected that there was a large amountof variability for nodule number, unless veryfew genotypes were in the study. Secondly,regarding the use of plant color in evaluatingfixation by different strains of Rhizobium, thedifferent botanical types of groundnuts themselvesvary in leaf color. Could we say ingeneral that the Virginia types have betternodulation than Valencia and Spanish types?J. C. WynneThe nodule varies with genotype, and ifenough genotypes are used then significantdifferences are recorded. The results shownwere limited and were not for all the experimentswe have conducted. We would not useleaf color for selection purposes. When weevaluate strains we use nitrogen-free soils andwe remove the cotyledons also. Color is then auseful parameter for comparison of strains ona single cultivar. Generally in North Carolina,we find that Virginia cultivars are the bestnodulators followed by Spanish and thenValencia botanical types.R. 0. HammonsNonnodulating lines were found by Dr. G or bet143

in Florida and now ICRISAT has isolatedmore nonnodulating types. What use will bemade of these nonnodulating lines?J. C. WynneI want to produce isogenic lines so we candetermine how much nitrogen is taken upfrom the soil and how much is fixed by theplant. Or. Elkin wants to study the nodulationprocesses.P. S. ReddyYou say that nodulation is genetically controlled;how many genes are involved?J. C. WynneDr. Nigam reported yesterday that two recessivegenes were involved in nonnodulation. Inother processes, quantitative genes are involved.M. V. R. PrasadI have a comment to make rather than aquestion. We have isolated an EMS-inducedmutant from the TMV-2 cultivar which has adifferent nodulation pattern. The parent hasmore nodules in the peripheral regions of theroot whereas the mutant has more nodules inthe deeper zones of the root.A. NarayananDr. Nambiar's results indicated yesterday thatnitrogen fixation occurs in groundnuts duringthe pod filling stages. This is in contrast tomany other legumes in which fixation ceasesduring the reproductive phase.P. T. C. NambiarWe believe there is genotypic variation in thisphenomenon as far as groundnuts are concerned.Some cultivars do continue to fixnitrogen during this stage.M. A. AliWhat are the effects of soil-applied pesticidesand herbicides on rhizobial activity and onother microbes in the soil?J. C. WynneWe found that in North Carolina some systemicinsecticides actually increased nodulationeither directly or indirectly. Some fungicidesdo decrease nodulation.P. T. C. NambiarIt depends on which chemical is used; wecannot generalize.P. J. DartIt has been found that if the herbicide affectsthe physiology of the plant then the nodulationis affected, but if the plant grows normallythen it is not affected. Not enough work hasbeen done on groundnuts but with Vicia faba,nematocides do not inhibit nodulation.D. H. SmithIs there mycorrhizal activity in groundnuts andis there any interaction between Rhizobiumand the mycorrhiza?P. J. DartGroundnut is mycorrhizal and some work hasbeen done on this in Bangalore. We hope tostart studies here soon. The big problem isthat the fungus cannot be successfully cultivatedyet. Chopping and applying the roots tothe soil may be a possibility but much morework is needed on this aspect.V. RagunathanThe method of applying Rhizobium to the seedand then drying the seed in theshadedoes notseem to be very satisfactory. Germinationseems to be affected by this method. What arethe other possibilities?P. T. C. NambiarWe are experimenting with sand as a carrier atICRISAT and this is placed below the seed atplanting. This is important when seed dressingsmay prevent direct application of inoculumto the seedcoat due to the danger ofthe seed dressing adversely affecting therhizobia.P. J. DartIn the USA, the granular inoculum is deliveredthrough a separate tube on the planter and isplaced below the seed. In Australia, soya isinoculated by a liquid inoculum again deliveredfrom a separate coulter. At ICRISAT, thefarm machinery section is experimenting withsingle machinery for delivering inoculum.Groundnuts need a large number of rhizobiato effectively nodulate them. Many of thecommercial inoculants in many countries do144

not meet the required quality and quantitystandard we know are necessary forgroundnut.PhysiologyH. M. IshagWe found that net assimilation rate (NAR) isnegatively correlated with leaf area index (LAI)from sowing to pegging and then there is asteady increase in NAR after pegging. What doyou consider are the reasons for this?D. E. McCloudI do not like the term NAR and I do not think ithas any physiological significance ingroundnuts. Leaf area increases beyond thetime that full ground cover is achieved. Thetotal canopy photosynthetic rate is more important,and I base my judgment on that.R. P. ReddyFor your model did you use the temperaturerecorded in the root zone or above groundaround the plant?D. E. McCloudWe used soil temperature around the peggingzone. We achieved this by using thermocouples.We made no attempt to controlthe actual temperature, which fluctuated duringthe season, but two of the treatments werewarmer and one was lower than ambient. Theactual figures shown were averaged for theseason.R. P. ReddyThe length of the podding period varies.Spanish and Valencia have a shorter podfilling period and they should be more efficienttranslocaters.D. E. McCloudIn our model, potential yields were looked forand we did not take into account pests, diseasesor drought. Spanish peanuts have ashort pod filling phase and have a lower yieldpotential than Virginia types, because only somuch photosynthate is available.J. GautreauYou have stated that there are two mainfactors for pod yield — good partitioning anda longer period for pod filling. I agree butthesecriteria are not valuable everywhere, particularlyfor low rainfall areas. Your criteria relateto areas with assured rainfall or where irrigationis available. The haulms are also importantin the SAT for cattle feed, so we must lookfor good foliar growth as well as good productionof pods.D. E. McCloudThank you for those comments and I agreewith them. Partitioning can go too high andyou can lose flexibility. In fact, in Florida thecultivar Early Bunch is only recommended forthe top growers who can manage their cropwell because this cultivar has a very highpartitioning rate.M. V. K. SivakumarIs it possible to put soil data into your model?D. E. McCloudYes, it could be put into our model. Dr. Ducan'sbig computer model in Florida does have thiscapacity.IntercroppingH. T. StalkerGiven the differences in crop values in bothcash and food value, do you recommend thatthe farmer should intercrop?M. S. ReddyYes, intercropping is a form of insurance andthere are socioeconomic reasons for it as well.In a dry year there is a good chance that one ofthe crops at least will survive to produce somesort of yield. Farmers are interested becausethere is a compensation effect in the total cropraised.G. D. PatilDr. Reddy uses the term intercropping, whenhe should be using the term mixed croppingas he is varying the number of rows of themain crop.M. S. ReddyI disagree. The term mixed cropping is definedas taking more than one crop within a single145

ow. Intercropping is when you grow crops indifferent row proportions. We have used areplacement series technique for cereal/groundnut intercrop experiments. It is importantto consider both crops in varying rownumbers.C. HarknessFor the peasant farmer, intercropping is veryimportant and there is strong evidence thatthe best use of the growing season is made byadopting this system. In Nigeria, for example,millet is planted on the first rains and can bereplanted if necessary. This is the early foodcrop for the farmer. When the rains are established,then groundnuts are planted in thegaps of the millet field. Later, if there are stillgaps, then other quick-maturing species, suchas Voandzeia (groundbeans), can be planted.This system is, of course, not for the largescale,mechanized farmer. More work isneeded on the pest and disease situation ofthe intercropped groundnut compared to thesole crop groundnut.146

Session 6Groundnut EntomologyChairman: W. ReedRapporteurs: D. V. R. ReddyP. Subrahmanyam

Resistance of Groundnuts to Insects and MitesW. V. Campbell and J. C. Wynne*Plants have the ability to repel attack by amyriad of pests. In some instances the level ofresistance may be low, but due to the ability ofthe plant to replace leaves or fruit, the plant willcompensate for damage by the pest and survive.Other plants may posses high resistance,even approaching immunity to a pest. Immunityto an insect pest is rare among commerciallyacceptable crops unless the concept of nonhostis considered immunity.Plants with resistance to insects and mitesoffer the most economical method of combatingpests. Unfortunately, pest-resistant cultivarsmust be competitive in the market to besuccessful. A pest management approach toinsect control, however, opens the way for useof more germplasm that offers low to moderateresistance to pest complexes. In the search forpest resistance most of the cultivars, breedinglines or species identified as resistant will haveeither low or moderate resistance levels. Lowmoderate or high resistance are relative terms.A plant cultivar with low resistance exhibits lessdamage from a pest than other cultivars grownin the area but may still suffer extensive pestdamage. In general, a groundnut plant with lowresistance may show 10-35% less insect damagethan the susceptible cultivar, a moderatelyresistant plant may show 35-65% less damage,and a plant with high resistance to an insect willexhibit greater than a 65% reduction in insectdamage compared with the local susceptiblecultivars.Mechanisms of ResistanceThey have been defined by Painter (1951) as* Professor of Entomology, and Associate Professorof Crop Science, respectively, North Carolina StateUniversity, Raleigh, North Carolina 27650, USANote: Paper Number 6617 of the Journal Series ofthe North Carolina Agricultural Research Service,Raleigh, North Carolina, 27650, USA.non-preference ( = antixenosis), antibiosis, andtolerance. Plant resistance may be due to anyone mechanism or any combination of thethreemechanisms.Non-preference is a negative response by apest to a plant as a source for food, shelter,oviposition or any combination. Those plantcharacteristics that either repel or cause theinsect to leave the host after a brief contact willcontribute to the host possessing a high level ofnon-preference resistance. Characteristics possessedby a plantthat may be mediated throughthe insects sensory system to cause a minordisruption in feeding or oviposition will result inlow resistance by non-preference mechanism.Antixenosis has been suggested as a substituteterm for non-preference by Kogan andOrtman (1978).Antibiosis is an adverse effect of the plant onthe normal metabolism of the insect. Thoseplants that cause higher mortality in any stageof insect development, shorten the life span ofthe adult, or reduce fecundity as compared withknown susceptible plants, are said to possessantibiosis as a mechanism of resistance.Tolerance is the response of the plant toinsect damage by compensation or replacementso that it can support an insect populationthat would cause extensive damageto other plants that are considered susceptible.Painter (1951) used the term pseudoresistanceto describe a transitory reaction of susceptibleplant to environmental stress. He distinguishedthree types of pseudoresistance:(1) Host evasion is a lack of synchrony betweenplant phenology and pest so that the plant is in agrowth stage that is less susceptible to pestdamage when the pest is most abundant;(2) Induced resistance is a temporary resistancebrought about by some physiologicalchange in the plant in response to soil moistureor soil fertility; (3) Escape is a lack of infestationand damage due to a low pest population orunequal pest distribution. Some insects forexample cause heavy damage on field borders149

and damage may decrease or become dilutedas the distance into the field increases.Pseu do resists nce can be inconvenient andtime consuming by causing susceptiblegermplasm to be retested. A retest shouldidentify lines that were selected as resistant butwere actually susceptible due to pseudoresistance.Nature of ResistanceThe basis of resistance may be biochemical orbiophysical (morphological). A pest-resistantcultivar may be developed without a knowledgeof the nature of the resistance. For the best useof resources to aid the farmer, resistantgermplasm needs to be identified first, then themechanisms for pest resistance can follow.Biochemical agents that may be associatedwith resistant plants have been identified formany crops and summarized by Norris andKogan (1980). This research requires the closecooperation of a natural-products chemist, anentomologist with a reliable bioassay method,and a good supply of the pest that is destructiveto the crop. The various chemicals identified asresponsible for resistance include the alkaloids,isoprenoids, aromatics, glycosides, and acetogenins.Biophysical characters that have been identifiedas associated with resistant cultivars includetoughness and thickness of leaves, stems,or roots, trichome type, and trichome number.Trichome characteristics have been most oftencited as a morphological character responsiblefor resistance of the host to pest species. It is nowonder that this character has been exploitedoften since it may be observed more readilythan internal characters such as thickness,sclerotization or lignification. Gross morphologicalcharacteristics of the plant associatedwith resistance such as plant growthhabit, plant part abnormalities, leaf surfacetexture, size and solidness of stem and shapemay be readily identified with a minimum ofspecial equipment other than hand lens ordissecting microscope.Observations of discrete differences in leaf,stem or pod thickness, solidness and internalorganization, as well as the presence and locationof lactifers will require histological preparationand staining to differentiate parenchymaand sclerenchyma. The scanning electron microscopehas added an important dimension tothe study of plant surface features that maycontibute to pest resistance or susceptibility.Methods of Evaluation for PlantResistance to PestsA number of general methods for evaluation ofgermplasm for pest resistance may be used forvarious pests with slight modification. Fieldmethods, however, will be quite different fromlaboratory or greenhouse methods for selectingpest-resistant germplasm because field testsinvolve multiple plants while laboratory testsusually are limited to individual plants or plantparts. Regardless of whether the evaluation forresistance is conducted in the field or laboratory,a knowledge of the biology, seasonal history,and damage potential of the pest as well asmethods for maintaining or rearing the testspecies is essential.Field EvaluationIf the insect pest is so destructive that it causesdeath to the plant, then individual plants thateither survive or exhibit low damage may beselected for retesting. If the experiment isplanted in a randomized block design withsingle or multiple rows, then entries may beevaluated for susceptibility to the pest by countingthe number of pests, the number of damagedplants, the number of damaged leaves,stems, or fruit, or by working outthe percentagedamage to a specific plant part.Individual plant evaluations for pest resistanceare desirable for F1 and F2 generationbreeding lines. If seed supply is abundant, it isdesirable to plant more advanced generationmaterial in three-row plots, especially if the pestunder investigation moves readily from row torow. Data then can be collected from the centralrow with the first and third rows acting asbuffers to absorb excess damage from adjacentplots.Groundnuts attacked by sucking plant pestssuch as the leafhopper or jassid and spidermites may be evaluated for resistance by countingthe number of pests per plant or number perleaf or number for 5 or 10 leaflets. Resistancerating may also be based on the number or150

percentage of leaves with leafhopper "hopperburn"or chlorosis from spider mite feeding(Campbell et al. 1976).Evaluation of groundnuts for resistance tosoil insects presents a greater challenge. Whenthe insect kills the plant, or causes it to wilt,or causes an abnormal color or size or growthpattern then plants must be dug and sampledfor damage and for the pest. Most soil insectsonly move a few inches in the soil, therefore, ahigh population of well distributed adults of thepests species is desirableforthe best resistanceratings.Natural field populations of the pest are oftennot adequate to obtain reliable evaluations forresistance without retesting excessive escapes.Trap cropping with alternate or very susceptiblehosts in or around the field will attract higherpest populations. If this technique does notprovide an adequate pest population, then alimited amount of the most importantgermplasm in the test may be planted in shortrows and covered by a walk-in cage and followedby the release of a sufficient number ofthe desired pest in the cage (Campbell, unpublished).Greenhouse EvaluationGreenhouse tests are desirable for evaluating asmall number of breeding lines or cultivarsintensively where insects or mites are availablein good supply from field sources or rearing.The entire greenhouse may be used as a largecage where a single or a complex of pests maybe released. Most often the plants are caged fora seedling evaluation test for resistance, or leafcages are used to confine a small insect orcolony on selected leaves to study the effect ofthe host plant on the feeding, survival, oroviposition of insects.Resistance to aphids may be evaluated in thegreenhouse by placing a known number ofaphids on each test plant and then determiningsurvival and rate of reproduction. A knownnumber of insect eggs or larvae of soil pestsmay be placed in the soil of each groundnutcultivar being evaluated for resistance to determineinsect damage and survival.Laboratory EvaluationInitial evaluation of large amounts of germplasmis usually not conducted in thelaboratory due to limited space, excessive timerequired to complete tests, and the need for astrong colony of rapidly reproducing pests.Laboratory evaluation for resistance is mostoften conducted on germplasm that has beenpreviously determined to be resistant in thefield or greenhouse and for which informationon the mechanisms of resistance is desired.Excised leaves or leaf discs cut with a corkborer from selected lines are often used inpreference to whole plants for space conservation.A susceptible standard must be used in atwo choice or multiple choice feeding or ovipositiontest for nonpreference evaluation. Anothertest should be conducted at the same timecalled a forced feeding or isolation test whereeach plant entry is isolated and separatelyinfested so the pest does not have a choice ofgermplasm for feeding or oviposition.Plant maturity as well as leaf age on the sameplant has a marked effect on the pest feedingand oviposition. Therefore, all plant partsevaluated for resistance should be collectedfrom plants of the same age and from leaves orfruit on the same position on the plant or sameage. Often mature leaves or mature fruit areunacceptable for food or oviposition regardlessof the plant susceptibility to the pest. Mostinsects prefer the younger, succulent leavesand fruit. There are exceptions, however, suchas stored product pests.Plastic shoe boxes, sweater boxes or refrigeratorhydrator boxes make suitable cagesfor conducting nonpreference tests. Isolationtests are often conducted in 100 or 150 mmdiameter petri dishes. Known numbers of insectsare introduced for a period of time, usually1-5 days for evaluation of feeding damage,larval development time, generation time, andreproduction.Antibiosis studies often conducted in thegreenhouse or laboratory involve isolation ofindividual insects on the plants being evaluatedfor resistance. Measurements are made of suchparameters as larval weight gain, pupal weightor survival, adult weight or survival, or length oftime for insect development. Longevity datamay be appropriate for some pests. Abnormallyhigh pest mortality, poor weight gain, slowdevelopment, or reduced fecundity are all indicativeof resistance due to an antibiosismechanism.151

Resistance of Groundnutsto Foliage Feeding InsectsT o b a c c o Thrips Frankllniellafusca Hinds.It attacks the plant as soon as it cracks theground and causes deformed leaves, smallleaves, stunted plants, and sometimes a delayof several weeks in flowering and pod formation.High populations of thrips will reduce yieldif they attack groundnuts when plants are smalland have only a few terminal leaves (Campbell,unpublished). Some very susceptible breedinglines have been killed by thrips in NorthCarolina.Field populations of thrips are alwaysadequate for evaluating cultivars and breedinglines for resistance in North Carolina. Ratingsfor resistance have been made by counting thenumber of thrips damaged leaves, or the percentageof leaves with thrips damage or thepercentage of the leaf area with thrips damage.The varieties NC-GP342 and NC-GP343 as wellas NC-6 (NC-GP343XVA 61R) have low levelresistance to thrips. Susceptible commercialcultivars exhibited two or three times morethrips damaged leaves than resistant lines(Table 1).Kinzer et al. (1972) developed a rearing methodTable 1. Differences among advanced breadinglinas in thripv damage. NorthCarolina.IdentityNo. thripsdamagedleaves aNC-GP 342 85.3Florigiant x AC 342 98.0NC-6 102.0AC 301 x NC-2 130.0NC-GP 343 x Florigiant 136.0NC-GP 343 146.7NC-GP 343 xNC-5 156.3NC-2 214.0NC-5 273.3Florigiant 285.3Florunner 296.7LSD (0.05) 58.62a. per 30 row ft.for the thrips using an artificial diet that yieldeda higher percentage of adult thrips thangroundnut foliage. This rearing method wouldbe useful for laboratory antibiosis tests andnonpreference studies.P o t a t o Leafhopper Empoascafabae Harris.In the USA the potato leafhopper flies northfrom the Gulf Coast region to infest peanuts.Leafhopper populations will vary each year butthe population pressure is sufficiently highevery year in North Carolina to obtain good fieldevaluation for pest resistance.Since the potato leafhopper causes "hopperburn,"a characteristic V-shaped yellowing onthe apical end of the leaflets, the number ofyellowed leaves, or the percent yellowed leavesor the percent leafhopper damage may becounted or visually estimated for assessingleafhopper resistance. Several North Carolinaaccessions were rated as having high resistanceto the leafhopper. They showed a 99% reductionin damage compared with NC-2 cultivar(Table 2).During the period since 1960 only a low levelof resistance to thrips has been observedamong the domestic peanutsArachis hypogaeaL. However, a number of wild species in sectionsRhizomatosae and Arachis appearednearly immunetotobacco thrips and the potatoleafhopper (Table 3). The wild species serve asan untapped reservoir for pest resistance untilthe necessary breeding techniques are developed.Fall A r m y w o r m Spodoptera frugiperda(J. E. Smith)The fall armyworm prefers monocotyledonousplants but they will infest groundnuts whenpopulations are high or suitable grasses are notavailable. Sometimes fall armyworms areattracted to groundnut fields due to excessgrass where they also feed on the groundnutfoliage. The fall armyworm is a migrating,sporadic pest of groundnuts that is more importantin the Georgia-Florida-Alabama productionarea than in the Virginia-Carolinaregion.Leuck and Skinner (1971), using laboratoryrearedfall armyworms reported adult152

Table 2.Resistance of groundnut accessions to the potato leafhopper. North Carolina.AVg. no. leaf-Avg. % leafhopper damaged hopper damage/leaves/30 row30 rowAccession Pedigree* ft. ft.10207 Recurved x (C12 x C37) 4.0 0.310247 (C12 x C37) x Recurved 10.0 1.010211 (C12 x C37) x Recurved 13.3 0.710277 (C12 x C37) x Recurved 31.7 2.015729 (C12 x A18) M 7 M 5 M 3 M 1 42.7 4.015730 (C12 x A18) M7M5M3M1 49.7 3.015745 (C12 x A18) M 7 M 5 M 1 69.0 3.315744 (C12 x A18) M 7 M 5 M 1 84.3 5.315736 (C12 x A18) M 7 M 1 92.9 9.315739 (C12 x A18) M 7 M 5 M 1 97.3 11.710272 (C12 x C37) x Recurved 142.7 10.7343 C12 x C37 157.7 15.0323 NC 2 493.0 66.7LSD (0.05) 43.0 6.1a. C12, C37 = NC Bunch x PI 121067; A18 = NC-4 x Spanish 2B; Recurved = irradiation mutant from NC-4.Table 3.Resistance of wild species of groundnuts to tobacco thrips and potato leafhopper (LH),North Carolina, 1979.Collectionname PI Collection SectionNo. thripsdamagedleaves aNo. LHdamagedleaves*A. sp 276233 GK 10596 Rhizomatosae 0 4.0A. glabrataBenth.A. macedoiKrap. etGreg, nom nudA. villosaBenth.A. stenospermaGreg, et Greg.nom nudA. batizocaeKrap. et Greg.nom nudA. monticolaKrap. et Rig.262797 GKP 9830 Rhizomatosae 0.5 0.5276203 GKP 10127 Extranervosae 0 0331196 B 22585 Arachis 0 0338280 HLK 408 Arachis 1.5 0.5298639 K9484 Arachis 0 0219824 K 7264 Arachis 18.5 0A. hypogaea NC-6 Arachis 39.0 20.0A. hypogaea Florigiant Arachis 44.0 57.0LSD (0.05) 16.17 14.31a. par 30 row ft.153

emergence was significantly reduced on SoutheastRunner 56-15 as compared with the susceptiblecultivar Starr. They reported PI 196613shortened the life cycle of the fall armyworm by2 days and caused high larval and pupal mortality.They concluded the mechanisms of resistancewere nonpreference or antibiosis.Corn Earworm Hellothis zea Bodie.The corn earworm invades groundnut fieldsusually during the peak bloom or fruit productionperiod. It feeds primarily on the foliagebut also cuts off pegs. Low to moderateresistance to the corn earworm has been observedamong the North Carolina breedinglines and in Early Bunch and NC-6 cultivars(Table 4). When the moth population is high,field screening for resistance is very successful.Evaluation for resistance may include a visualestimate of earworm defoliation or larvae maybe dislodged from plants with a wood doweland counted on the ground between rows.A laboratory experiment was conducted todetermine if low H. zea field damage observedon NC-6 cultivars was due to antibiosis. Five,4-day old larvae were isolated on NC-6, NC-2,and Florigiant. In 10 days, larvae fed youngleaves from NC-2 and Florigiant weighed approximatelythree times more than larvae fedyoung leaves from NC-6 (Table 5). This isevidence that a mechanism of corn earwormresistance in NC-6 is antibiosis.Table 4. Resistance of groundnuts to the cornearworm (CEW) (Hallothis xeaBodie), North Carolina.Entry%CEWfoliagedamageEarly Bunch 4.7NC-6 7.3Shulamit 13.0NC-5 13.3Avoca 11 15.0NC-2 18.0Florigiant 19.3LSD (0.05) 5.48CV(%) 23.25Table 6. Antibiosis as a mechanism of resistanceof NC-6 to the com earworm(CEW), North Carolina.CultivarNC 6NC 2FlorigiantLSD (0.05)Spider MiteTwospotted Spider MiteTetranychus urticae Koch.CEW avg.weight(g)0.01920.05340.06630.0208The twospotted spider mite causes extensivedamage to groundnuts grown in light, sandysoil that are under drought stress, especiallyfollowing a multiple application of foliageappliedfungicides and insecticides. Due to thehigh reproductive potential and multiple generationswithin a growing season, there alwaysexists a good possibility of a mite populationshowing resistance to a chemical miticide. Mitepopulations have developed resistance to someorganophosphorus insecticides. There is a needto search for mite resistance in the cultivated andwild species of groundnuts.Natural infestations of mites are not alwaysdependable; therefore it is desirable to maintaincolonies of mites for field distribution or forlaboratory or greenhouse experiments. Mitesmay be reared on lima bean plants in thelaboratory by inoculating the beans with mites7 days after planting. Lima beans are more suitablefor mass rearing than groundnuts due tothe large amount of foliage produced in a shorttime. Plants may be infested in the field bytransferring two or three bean leaves to thecenter of each entry. Resistance then may bebased on the mite buildup from the releasepoint and measured by counting the number ofmites on a 5 or 10 leaflet sample.Laboratory or greenhouse experimentsshould be more precise in the number of mitesreleased, for example, the release of onefemale, one pair, 100 eggs, or 50 adults. Thesmaller number would be released on excised154

leaves or leaflets and the larger number onwhole plants.Representatives of seven sections of thegenus Arachis weretested in the greenhouse inNorth Carolina for resistance to the twospottedspider mite. The highest mite resistance wasfound in the section Rhizomatosae. ResistantRhizomatosae exhibited as much as 90% lessmite damage than the most susceptible entries(Table 6). Leuck and Hammons (1968) alsoreported high resistance among the wildspecies to a closely related mite Tetranychustumidellus Prichard and Baker. They reportedthat PI 262841 and PI 263396 possessed highresistance.Soil Insectssandy soils and most destructive under droughtstress conditions. Loss of young plants mayoccur if the infestation is early or the crop isplanted late. The larvae tunnel into the stems,root, pegs and pods.Plant introductions were tested in NorthCarolina in single row, replicated plots undernatural field infestations. PI 269116, 269118, and262042 exhibited the lowest damage (Table 7)but there was no evidence of high field resistanceto the lesser cornstalk borer.Leuck and Harvey (1968) collected eggs of thelesser cornstalk borer on cheesecloth and artificiallyinfested greenhouse plots of groundnutintroduction with eggs. There was a wide rangein seedling survival but the best plant introductionshad 26-29 plants surviving from 30 seedsplanted.Lesser Cornstalk BorerElasmopalpus lignosellus (Zeller)This pest occurs throughout the peanut growingarea in the USA and is most abundant inSouthern Corn R o o t w o r mDiabrotlca undecimpunctatahowardi BarberUnlike the lesser cornstalk borer, the rootwormTable 6. Resistance of wlld spacies of groundnuts to the twospotted spldar mlte.Graanhousetast,North Carolina, (Johnson at al. 1977).Collectionname PI Collection Section% mitedamage 8A. monticola 219824 K 7264 Arachis 96.5aA. stenospermaGreg, et Greg.nom nud338279 HLK 408 Arachis 93.5abA. hypogaea Florigiant Arachis 83.7a-dA. hypogaea NC-5 Arachis 72.5cdA. villosa 331196 B 22585 Arachis 45.0fgA. sp 276233 GK 10596 Rhizomatosae 24.2h-jA. correntinaKrap. et Greg.nom nudA. glabrataBenth.A. macedoiKrap. et Greg.nom nud331194 GKP 9548 Arachis 21.0ij262797 GKP 9830 Rhizomatosae 15.7ij276203 GKP 10127 Extranervosae 15.2ijA. sp 338317 HLO 335 Rhizomatosae 9.2ja. Means with the tame letter are not significantly different at the 5% level according to Duncan's Multiple Range Test.155

Table 7. Differences among groundnuts inlesser cornstalk borer damage. NorthCarolina.IdentityNo. damagedpegs + pods"PI 269116 22.7PI 269118 23.0PI 262042 28.7NC-4 30.0PI 275744 30.7Schwartz 21 36.7PI 275743 37.3PI 269005 39.3New Mexico Valencia 44.7NC-5 50.7NC-15745 54.0NC-2 57.0Florigiant 89.0Starr 99.0NC-6 111.3Comet 125.7Florunner 129.3LSD (0.05) 44.4CV(%) 41.0a. per 3 plant sample.prefers moist, heavy, high organic matter soiland cannot tolerate dry sandy soil. The adultrootworm causes minor damage to the terminal,unopened leaves but the larvae are capableof destroying ail the pegs and pods. Severerootworm damage occurred in some areas inNorth Carolina when the rootworm developedresistance to a popular insecticide.In 1960 research was initiated to find rootwormresistant germplasm. Plant introductionsand selections from the North Carolinagermplasm collection were screened in fieldtests. Tests were established in soil with goodmoisture retention properties and generallywith an organic matter content of 1.5-3.5%.Promising lines were tested for 5 years, crossedwith commercial cultivars, and then retestedand selected for 10 more years. In 1976 acultivar with high resistance to the rootwormwas released as NC-6, a cross between theinsect resistant parent NC-GP 343 and Va 61R(Campbell et al. 1977).'The yield and acre value of NC-6 weresuperior to Florigiant in fields where the rootwormwas a problem and it competed favorablyin the market for quality and price (Wynne etal. 1977). NC-6 and other accessions with NC-343germplasm exhibit approximately 80% lessrootworm damage than Florigiant (Table 8). Thislevel of resistance is sufficiently high to eliminatethe need for chemical control of the rootwormin most North Carolina soils.Table 8. Resistance of groundnuts to thesouthern corn rootworm. NorthCarolina.No. rootwormAccessiondamagednumber Identity pegs + pods b17201 AC 343 X VA61R 10.017167 NC-6 a 13.317205 AC 343 x NC-5 18.715973 Florunner 23.017215 NC-5 X VA 61R 34.017163 NC-5 x Florigiant 40.3323 NC-2 58.7333 NC-5 69.3348 Florigiant 105.817211 NC-5 x Florigiant 108.7LSD (0.05) 24.4CV(%) 33.4a. AC 343 x Va 61Rb. 5 plant sample.Multiple Insect and MultiplePest ResistanceCultivar NC-6 is unique in that it possessesmultiple insect resistance. It was developed forhigh rootworm resistance but it also has a lowlevel of resistance to thrips, moderate resistanceto the potato leafhopper and moderateresistance to the corn earworm. NC-6 is susceptibleto the lesser cornstalk borer and does notoffer any special advantages against the twospottedspider mites.NC-6 has now been crossed with a NorthCarolina breeding line NC-3033 that has resistanceto Cylindrocladium black rot (CBR), adestructive disease in many fields in theVirginia-Carolina production areas. Some NC-6xNC-3033 progeny have multiple insect resistancethat is equivalent to NC-6 (Table 9). Selec-156

Table 9. Evaluation of breeding lines for multiple pest resistance. North Carolina.No. thrips No. LH b %damaged damaged CEW CEntry Identity a leaves/30 ft. leaves/30 ft. damage/30 ft.13 NC-6 173.3 68.7 1.38 IMC-6 x NC-3033 184.7 95.7 1.74 NC-6 x NC-3033 193.3 43.7 1.36 NC-6 x NC-3033 213.3 45.3 2.71 NC-6 x NC-3033 229.7 31.7 1.314 NC-2 334.3 414.7 9.012 Florigiant 493.7 310.0 7.3LSD (0.05) 71.86 59.27 2.62a. NC-6 has multiple Insect resistance and NC-3033 Is resistant to Cylindrocladium black rot (CBR).b. Potato leafhopper Empoasca fabae.c. Corn earworm Heliothis zee.tions are made among the progeny of NC-6xNC-3033 with multiple insect resistance andCBR resistance. The objective is the releaseof a high yielding, multiple pest resistantgroundnut. Care must be exercised to avoid therelease of a cultivar that is resistant to one pestbut very susceptible to other important pests.Although pest problems differ from countryto country, many of the insects discussed occurworldwide. Closely related species have similarhabits and similar destructive potential. Conceptsare useful and modification in techniquesmay be needed with specific local populationsand resources.ReferencesCAMPBELL, W. V., EMERY, D. A., and WYNNE, J. C. 1976.Resistance of peanuts to the potato leafhopper.Peanut Science 3: 40-43.CAMPBELL, W. V., WYNNE, J. C, EMERY, D. A., andMOZINGO, R. W. 1977. Registration of NC 6 peanuts.Crop Science 17: 346.JOHNSON, D. R., WYNNE, J. C, and CAMPBELL, W. V.1977. Resistance of wild species of Arachis to thetwospotted spider mite, Tetranychus urticae.Peanut Science 4: 9-11.KINZER, R. F., YOUNG, SHARON, and WALTON, R. R. 1972.Rearing and testing tobacco thrips in the laboratoryto discover resistance in peanuts. Journal ofEconomic Entomology 65: 782-785.KOGAN, M„ and ORTMAN, E. E. 1978. Antixenosis — anew term proposed to replace Painter's nonpreferencemodality of resistance. Entomological Societyof America Bulletin 24.LEUCK, D. B., and HAMMONS, R. O. 1968. Resistance ofwild peanut plants to the m ite Tetranychus tumidellus.Journal of Economic Entomology 61: 687-688.LEUCK, D. B., and HARVEY, J. E. 1968. Method oflaboratory screening of peanut germplasm for resistanceto the lesser cornstalk borer. Journal ofEconomic Entomology 61: 583-584.LEUCK, D. B., and SKINNER, J. L 1971. Resistance ofpeanut foliage influencing fall armyworm control.Journal of Economic Entomology 64: 148-150.NORRIS, 0. M., and MARCOS KOGAN. 1980. Biochemicaland morphological bases of resistance. Pages23-61 in Breeding plants resistant to insects. (F. G.Maxwell and P. R. Jennings, eds.). John Wiley andSons, New York.PAINTER, R. H. 1951. Insect resistance in crop plants.The Macmillan Co., New York. 520 pp.WYNNE, J. C, CAMPBELL, W. V., EMERY, D. A, andMOZINGO, R. W. 1977. NC 6, a southern com rootwormresistantpeanut variety. North Carolina AgriculturalExperiment Station Bulletin 458: 15 pp.157

Groundnut Pest Research at ICRISATP. W. A m i n and A. B. M o h a m m a d *Initially research was concentrated on thoseparticular pest problems which were of immediateconcern at the ICRISAT Center. Simultaneously,information was collected on themost important pest problems of the crop in theSemi-Arid Tropics (SAT). This paper brieflyreviews the progress made since groundnutpest research started at ICRISAT in late 1977.Identification of Pest ProblemsGroundnut Pests at ICRISATAt ICRISAT the insect fauna from groundnutswas collected from 1 0 x 1 0 meter sized plots ofthree cultivars with erect bunch (cv TMV-2),spreading bunch (cv Robut 33-1), and runner(cv M-13) growth habits replicated three timesin pesticide-free and pesticide-affected areas.Over 70 insect and other pests of groundnutswere collected.The seasonal abundance of the various insectswas also studied in plots of the groundnutcv TMV-2 raised at several locations on bothAlfisols and Vertisols on the ICRISAT farm. Thecrops were sown monthly from June throughFebruary, individual plots being sited at least400 m away from other groundnuts. Informationon the abundance of insects in relation tolocations, soil types, pesticide-free or affectedareas, seasons, and years was recorded.Termites and wlreworms were most abundantin Alfisols while earwigs and millipedeswere more abundant in Vertisols. In Vertisolsleaf miner was more prevalent in some locationsthan others. Thrips injury was more pronouncedwindward than leeward locations.Barriers across the prevailing winds affectedthrips distribution; smaller numbers of thripswere observed on the plants in the vicinity offield bunds to the leeward side. Some insects* Entomologists, Groundnut Improvement Program,ICRISAT.became more abundant in drought years;Caliothrips indicus, leaf miner, Aproaeremamodicella, and aphid Aphis craccivora weremore abu ndant in th e drought year of 1979 th anin the good rainfall year of 1978. In normalyears, insects such as thrips (Scirtothrips dorsalisand Frankliniella schultzei) were abundantin both rainy and postrainy seasons, Spodopteralitura and Aproaerema modicella in thepostrainy season, Aphis craccivora in the summerseason, and Empoasca kerri in the rainyseason. Heliothis armigera was an importantflower feeder in both rainy and postrainy seasons.(Fig. 1).Groundnut Pests in IndiaIn India insect pests are major constraints onyields, being particularly important in the statesof Andhra Pradesh, Tamil Nadu, Punjab, Rajasthan,Gujarat and Maharashtra. About two decadesago, only a few insects were regarded asimportant pests (Rai 1976) but the situation haschanged considerably. Insects like Spodopteralitura, Frankliniella schultzei, Scirtothrips dorsalisand Empoasca kerri which were not consideredimportant pests then, are now so recognized(Table 1).Insects such as leaf miner have been spreadingand considerable damage by this insect wasreported for thefirsttimefrom Gujarat and fromthe Dhuliadistrict of Maharashtra in 1978. Whitegrubs (Lachnosterna consanguinea) have compelledmany farmers to abandon groundnutcultivation in sandy soils of Gujarat, Rajasthan,Uttar Pradesh, and Punjab.Groundnut Pests in SATOn the world scene, over 300 species of insectpests have been recorded from groundnuts butonly a few are important worldwide and a fewothers in restricted regions (Table 2). Some areimportant as vectors of viral diseases (Table 3).Insects are important as quality reducers and158

FrankliniellaSchultzei perterminal leafScirtoth ripsdorsalis perterminal leafEmpoasca kerriper three terminalleavesStomopteryxsubsecivella minesper plantHefiothis armigeraand Spodoptera lituralarvae per plantFigure 7. Major pests of groundnut at ICRISAT and their seasonal distribution.Table 1.Year 1968 aMajor pasts of groundnut in India.Year 1979 b1. Aphis craccivora 1. Lachnosternaconsangumea2. Aproaerema modicella 2. Aphis craccivora{Stomopteryxsubsecivella)3. Amsacta spp 3. Aproaerema modicella[Stomopteryxsubsecivella)4. Microtermes sp and 4. Amsacta albistrigaOdontotermes sp5. Heliothis armigera6. Spodopetera litura7. Frankliniella schultzei8. Scirtothrips dorsalis9. Empoasca kerri10. Odontotermes obesus11. Pod scarifying termitesa. Rai, B. K. 1976. Pests of oilseed crops In India and theircontrol. Indian Council of Agricultural Research, NewDelhi.b. From field trips, literature, and correspondence.there are many storage pests against whichstrict quarantine is in vogue, e.g., Caryedonserratus, Trogoderma granarium. The literatureon groundnut insects from Commonwealthcountries has been reviewed by Feakin (1973),for the USA by Bass and Arant (1973), and briefreview of world pests by McDonald and Raheja(1980).Studies on the Thrips Vectorsof Bud Necrosis DiseaseThrips-borne bud necrosis disease caused bytomato spotted wilt virus is an important diseasein India (Table 4) and ICRISAT (Table 5). Ahigher incidence was observed in the rainyseason than in the postrainy season. A majorepiphytotic occurred in 1979 when the infectionlevel in unsprayed crops reached 80-95%.In the subsequent postrainy season lessthan 30% infection was recorded in unsprayedplots. Infection levels were lowest incrops sown in September and October and fromFebruary - May.159

Table 2.Major Arthropod pesta of groundnut. aRegions where seriousAsia Africa Americas* AustraliaSucking Aphis craccivora Aphis craccivorapests Empoasca kerri Empoasca dolichi Empoasca Austrasca spScirtothripsdorsalisFrankliniellaschulaeiCaliothripsindicusEmpoasca facialis fabaeEnnoethripsflavensFrankliniellafuscaParaplobia spFoliage Spodoptera Spodoptera Spodoptera Spodopterafeeders litura littoralis fungiperda lituraHeliothis Heliothis zea HeliothisarmigeraAproaeremamodicellaAmsacta sppFeltiasubterraneaAnticarsiagemmatilisarmigeraRoot feeders Lachnosterna sp HildapetruelisOdontotermes sp MicrotermesthoracalusRhopaeamagnicornisHeteronyx spPod feeders Microtermes sp Microtermes sp DiabroticaEtiella Elasmolomus undecimzinckenellasordidus punctataElasmolomus Peridontopyge Pangeassordidussp.Caryedonserratusbilineatusa. Feakin, S. D. 1973. Pest control in groundnut, PANS Manual No. 2. COPR, London.b. Mainly from Bass, M. H. and Aran!, F. S. 1973. Pages 383-428 In Peanuts-culture and uses.The epiphytotics of the disease were associatedwith an abundance of the major vectorFrankliniella schultzei. Investigations over thelast three years have given some useful information:1. The major vector, Frankliniella schultzei isa polyphagous thrips species. Populations ofthese thrips are lowest during summermonths when they survive mainly in flowersof wild plants, cultivated summer crops, andornamentals. Cassia sp, Ageratum conyzoides,Tridax sp, Tribulus sp, and Calltropissp are some of the important weeds thatharbor F. schultzei while greengram, blackgram, and cowpea are important crop hosts,and marigold and chrysanthemums are importantornamentals. The thrips migrate tothe crops which are sown early or to theweeds particularly Cassia sp and Ageratumsp that emerge soon after the first few monsoonshowers. The populations build up onthese hosts.2. Migrations to groundnuts take placethroughout the season but the large scalemigrations occur in August and January. Thethrips are carried on the prevailing winds andmainly at dusk. The disease infection is associatedwith immigrant thrips and secondaryspread is not important Crops sownearly largely escape from the disease (Fig. 2).The number of immigrant thrips is independentof the number of plants per unit area. A160

higher plant stand results in a proportionaldecrease in the percentage of infected plants.3. Early infection can lead to a total yield loss.Infection during flowering and peggingstages results in substantial reduction in thenumbers of flowers produced, the duration ofTable 3.Insect vactors of virus/mycoplasma diseases of groundnut. aDiseases Vectors RegionsRosette Aphis craccivora African continentPeanut spotted wilt* Thrips tabaci Brazil, South Africaand AustraliaBud necrosis bFrankliniella cIndiaschultzeiYellow spot Scirtothrips dorsalis c IndiaPeanut mottle Aphis craccivora USA, China, MalaysiaPeanut stunt Aphis craccivora USAWitches' broom Orosius sp Indonesia, JavaRugose leaf curl Not known AustraliaMarginal chlorosis Not known Papua New Guineaa. Feakin, S. D. 1973. Pest control in groundnut, PANSManual No. 2. pp.197 - Centre for Overseas Pest Research, London.b. Caused by tomato spotted wilt virus.c. Amin, unpublished.Table 4.Bud necrosis disease incidence on groundnut crops in India."Percent diseaseStates Region incidence YearAndhra Pradesh Hyderabad 50-60 197850-90 1979Coastal 0-5 1978Central 0-20 1979Karnataka Eastern 0-2 1978Southern 0-2 1978Maharashtra Eastern 0-5 19770-5 19780-5 1979Western 0-5 197720-50 1980Punjab 2-10 1977Uttar Pradesh Western 10-25 197840-50 19790-5 1980Tamil Nadu Western 15-20 1978Gujarat Saurashtra 0-10 19770-5 19790-5 1980North Eastern 0-5 197720-60 1980a. Estimates from field trips of Groundnut Program scientists of ICRISAT.161

Date of observationFigure 2. Effect of sowing dates on bud necrosis disease incidence, rainy season 1979.Table 5.Incidence of bud necrosis disease ongroundnut at ICRISAT Center. aPercentdiseaseYear Season incidence1977 Rainy 50-60Postrainy 45-561978 Rainy 60-80Postrainy 45-551979 Rainy 90-100Postrainy 20-301980 Rainy 80-90a. Figures for unprotected plots.the flowering period, peg length, and podgrowth. Infection in the late stages reducesyield but to a lesser extent than does earlyinfection.4. Some cultivars appear less susceptiblethan others to field infection by the disease.Robut 33-1 is one such cultivar; it has a highyield potential and is commercially acceptable(Table 6).5. Insecticides are generally not effective inreducing the disease incidence, unlessTable 6. Bud necrosis disease incidence instandard cultivars during differentseasons in unsprayed plots.Percent diseaseIncidenceSeason TMV-2 Robut 33 -1 M-13Rainy 1978 s86.8Postrainy 1978* 48.5Rainy 1979*100.0Postrainy 1979 c 34.4Rainy 1980 b 93.8a. Nonreplicated plotsb. 3 replicationsc. 4 replications33.628.250.220.535.360.637.057.127.840.8applied twice a week throughout the season.Insecticide applications during thrips immigration,requiring 3-4 sprays, is as effective as12 sprays applied at weekly intervals throughthe cropping season.Based on the above findings, a combinationof cultural and insecticidal methods was recommendedto reduce damage from the disease.This consisted of: (1) early sowing (about6 weeks before mass immigration of thrips), (2)higher plant density, (3) use of less susceptiblecultivars, and (4) use of insecticides during162

thrips immigration. When all these practices arefollowed, substantial reductions in disease areobtained (Table 7).Screening Germplasmfor Pest ResistanceFour insects which are important worldwideand also occur at ICRISAT were selected forscreening. The general screening procedure andobjectives are given in Figure 3. The insectswere thrips (Frankliniella schultzei), jassids(Empoasca kerri), and termites which causedpod scarification. Screening against aphidsAphis craccivora was done in the glasshousebecause populations of aphids were not highenough in the field, except during June and theearly part of July.ThripsFrankliniella schultzei infestation resulted in ascarring of foliage and distortion of leaf margins.An injury rating scale of 1-9 was used ininitial trials (1 = n o injury; 9 = distortion ofmargins). Promising lines were advanced andselections were made by visual scoring. Thelower susceptibility of some of these lines andwiId Arachis sp was confirmed in the laboratoryby studying the fecundity of thrips (Tables 8a,8b). Some ofthe promising lines have been sentto the USA and Brazil for further testing whereFrankliniella fusca and Enneothrips flavens areimportant thrips pests.JassidsThe major jassid pests of worldwide impor-Table 7.Effect of various cultural practices and insecticldal regimes on the incidence of budnecrosis disease.Basis forSowing Plant density insecticide* Percent diseasedate (000/ha, approx) Cultivar treatment incidenceRobut 33-1 (T) Thrips invasion*Weekly schedule28.523.9120TMV-2(S) Thrips invasion 57.2Early Weekly schedule 60.4(15June)80Robut 33-1(T)TMV-2(S)Thrips invasionWeekly scheduleThrips invasionWeekly schedule36.132.183.581.3Robut 33-KT) Thrips invasionWeekly schedule48.059.8120TMV-2(S) Thrips invasion 92.5Normal Weekly schedule 94.2(15July)80T. Cultivar with tolerance to virusS - Cultivar susceptible to virusa. Dimetheate 400 ml/hab. Based on thrips catches In suction trap.Robut 33-KT)TMV-2(S)Thrips invasionWeekly scheduleThrips invasionWeekly schedule51.149.992.894.8163

Figure 3. Basic scheme for identification and utilization of multiple pest resistanceltolerance.Table 8a. Fecundity of Franklinlella achultzaion some cultivars of groundnut.CultivarNC Acc 2243NC Acc 2232NC Acc 2214TMV-2Table 8b.SpeciesA. chacoenseA. glabrataA duranenslsA. hypogaea (cv TMV-2)No. eggs/female4.04.88.515.0Fecundity of Franklinlalla schulttmlon different Arachis species.No. eggs laid by10 females in 24 hours00444tance belong to the genus Empoasca. In Indiaand at ICRISAT, Empoasca kerri is the dominantspecies. Jassid injury results in tip yellowingand tip burn. Initial evaluations were done onthe basis of the number of leaflets showinginjury in 100 randomly collected leaflets, andsubsequent evaluations by counting thenumber of jassid nymphs on three terminalleaves of 10 plants of individual accessions.Some promising lines with resistance to jassidsare given in Table 9.Recently, it has been observed that Empoascakerri nymphs and adults cause irreversible wiltingin seedlings. Further laboratory screeningtrials are planned.AphidsIn preliminary glasshouse trials, five pottedplants of each accession were subjected to highaphid attack by placing them near aphid-infested164

Table 9. Some promising germplasm against Empoasca karri.GrowthAverage no ofCultivar habit jassid nymphs a Range* SusceptibilityNC Acc 2214 Runner 2 0-5 R" 2232 " 3 2-6 R" 2243 " 5 3-13 R" 2240 " 5 1-8 R" 2242 " 5 3-10 R" 343 " 13 9-20 MRM-13 " 19 10-43 SNC Acc 2462 Spreading bunch 15 10-19 MR" 2477 " " 14 10-17 MRRobut 33-1 " " 39 17-41 SNC Acc 2663 Erect bunch 17 12-25 MR" 2888 " " 15 9-20 MR" 406 " " 14 5-19 MR" 489 " " 15 11-18 MRTMV-2 " " 31 15-57 Sa. Nymphs were counted from three terminal leaves each from ten plants. Average for three replications.b. Number of nymphs per ten plants.B = Resistant, MR - Moderately resistant, and S = Susceptible.plants. The accessions showing more than 25aphids per plant were rejected. The same procedurewas applied to wild relatives of Arachis.One accession and several wild species thatshowed promise were tested in the laboratory.The results are shown in Table 10.TermitesAt ICRISAT, pod scarifying termites (species notidentified) occur in pesticide-free Alfisols. A onehectareplot where the termite population washigh was set aside for screening. Termite buildupwas encouraged by avoiding the use ofpesticides and deep cultivation, and by supplyingbamboo pegs for food during off seasons.The distribution of termites was studied bydistributing bamboo pegs throughout the plot.Many pegs were attacked indicating a fairlyuniform distribution of termites. The scarificationof pods was studied in pods attached toplants as well as in detached pods. TheTable 10. Number of progeny produced by Aphis cracclvora on the detached shoots of twocultivars of Arachis hypogaaa and Arachis chacoansa.TotalTotal no.no. ofCultivars/ No. of of adults nymphs Nymphs/wild species trials used produced femaleA. chacoense a 9 92 30 0.3A. hypogaea:NC Acc 2214(8) 4 54 61 1.1NC Acc 2214(7) 15 143 319 3.2TMV-2 b 10 94 1308 14.0a. Resistant checkb. Susceptible check165

technique of testing detached pods has beenfurther improved by baiting the pods with acowdung slurry which attracts termites. Suchpods are buried near the bamboo pegs thathave been attacked by termites. Some cultivarshad much less termite damage than others. Afew lines that showed very low damage for twoseasons are being further tested.ReferencesBASS, M. H., and ARANT, F. S. 1973. Peanuts — cultureand uses. Pages 383-428 American Peanut ResearchEducation Association. Stone Printing Co.,Virginia, USA.FEAKIN, S. D. (ed.) 1973. Pest control in groundnuts.PANS Manual No. 2, Centre for the Overseas PestResearch, London.MCDONALD, D., and RAHEJA, A. K. 1980. Advances inlegume science. (Summerfield and Bunting eds.)./nThe Proceedings of the International Legume Conference,Kew, England, 31 July-4 August 1978.RAI, B. K. 1976. Pests of oilseed crops in India and theircontrol. Indian Council of Agricultural Research,New Delhi.168

Session 6 — Groundnut EntomologyDiscussionM. V. R. PrasadYou have mentioned that the number ofsprays for controlling bud necrosis diseasewere reduced from 16 to 4. How did youachieve this? How it is applicable to the farmers?P. W. AminThis was done by monitoring thrips usingsuction traps and applying the insecticidalsprays during thrips migration. Earlier wewere using a fixed schedule of weekly sprays,and thus up to 16 sprays were applied. However,it is difficult for farmers to know when thethrips are invading the crop. Thus it is advisableto follow early sowing and to use lesssusceptible cultivars.S. M. MisariYou have mentioned that pegs were alsoinfested by aphids. What effect does this haveon pegs?P. W. AminUsually aphids infest groundnuts in lateAugust and on an average seem to cause 15%damage through desapping of plants andaffecting the growth.S. M. MisariWhat is the nature of damage? Are the ovariesaborted due to aphid infestation or the podformation occurs but leads to decreased shellingpercentage?P. W. AminThis has not been specifically investigated.N. D. DesaiDo you have any program for screeninggermplasm for resistance against whitegrubs? And can you suggest any good chemicalcontrol for white grubs?P. W. AminGroundnut crop at ICRISAT is not infested bywhite grubs and therefore we are not workingin this area yet. But, several scientists in Indiaare working on the control of white grubs.D. R. C. BakhetiaWe have been working on the control of whitegrubs in Punjab. We found that the applicationof granular insecticides such as isofenphosand carbofuran was very effective.P. W. AminWhite grubs are polyphagous and it may bedifficult to find sources of absolute resistance.However, it should be examined.D. R. C. BakhetiaIn the screening trials the criterion that youhave used, percent plant damage, to assessthe resistance of a cultivar may not be veryaccurate. Is it necessary to take into considerationthe different levels of damage underspecific environmental conditions?W. V. CampbellIt is important to use the extent of damage as acriterion because it shows a sum total of allfactors, e.g., insect number, cultivar, environment,etc.T. P. YadavYou rely mainly on natural infestation forscreening. Is it acceptable?P. W. AminWe do prefer screening under field conditions;however, we also do laboratory testing forlocating sources of resistance as in the case ofaphids.W. ReedAssessment of damage in the field is astraightforward and reliable criterion.167

Session 7Groundnut PathologyChairman: J. S. ChohanRapporteurs: I. S. CampbellA. B. MohammadD. J. NevillA. K. Singh

Cylindrocladium Black Rot (CBR)Disease of Peanut (Arachis hypogaea)Marvin K. Beute*Cylindrocladium black rot (CBR) of peanut[Arachis hypogaea L.) caused by Calonectriacrotalariae (Loos) Bell & Sobers (Cylindrocladiumcrotalariae [Loos] Bell & Sobers), wasfirst described as occurring in Georgia, USA in1965 (Bell and Sobers 1966). It was reported tooccur in South Carolina in 1968 (Garren et al.1972) and North Carolina and Virginia in 1970(Garren et al. 1971, Rowe et al. 1973). CBR wasfound on peanut in Japan in 1970 and wassubsequently regarded as a major disease ofpeanut in 1971 (Misonou 1973). Although CBRnow occurs in certain areas of Alabama andFlorida as well as Georgia and South Carolina,CBR is only considered a disease of seriouseconomic importance in the USA in NorthCarolina and Virginia.The effect of CBR on peanut is reported tovary from debilitative to destructive dependingon host resistance, environmental conditions,and inoculum density in soil. First symptoms ofCBR in the field ranged from chlorotic, stuntedplants to slight wilting of larger plants (Rowe etal. 1973). In newly infested fields symptomswere usually confined to one or several irregularareas within a field. In fields with a priorhistory of CBR, diseased plants were evenlydistributed, giving a ragged appearance to anentire field. Tap roots of chlorotic, stuntedplants were severely blackened and usuallysevered by decay at the junction of thehypocotyl and tap root, approximately 4-6 cmbelow the soil surface. Lateral roots on suscep-* Professor of Plant Pathology, North Carolina StateUniversity, Raleigh, North Carolina 27650, USA.Paper Number 6621 of the Journal Series of theNorth Carolina Agricultural Research Service,Raleigh, North Carolina, USA.The use of trade names in this publication does notimply endorsement by the North Carolina AgriculturalResearch Service of the products named, norcriticism of similar ones not mentioned.tible peanuts were either blackened or completelysevered 1-2 cm from the tap root.Diagnosis of CBR was aided by the abundantproduction of red perithecia which occur at thebase of infected stems under moist conditionsin fields. In areas under drought stress or infields with severely stunted plants, peritheciawere observed sparingly, if at all. Peritheciawere found on intact stems, pegs, and pods onand under the soil surface, but never on decayingplant debris in proximity to infected tissues.Extensive efforts to develop chemical controlfor CBR have not been productive (Rowe et al.1974). Resistance to CBR in peanut genotypeswas reported in 1975 (Wynne et al. 1975), butprogress in development of resistant cultivarswas initially hampered by lack of knowledgeconcerning the biology of C. crotalariae andepidemiological aspects of the disease.BiologyFungus ReproductionC crotalariae produced conidia, ascosporesand microsclerotia (ms) in culture and infectedplants (Jackson and Bell 1969). Conidia wererarely observed under field conditions but werecapable of causing necrosis of roots and pods ofpeanut (Beute and Rowe 1973). Conidia werenot considered to be important in the spread ofCBR because of their infrequent occurrence inthe field and limited viability due to a highsusceptibility to desiccation.Perithecia of C. crotalariae were reported toform abundantly on infected stems, pegs, pods,and hypocotyls of peanut at the soil line ifsufficient moisture was present (Rowe andBeute 1975). Under high moisture conditionsascospores could be detected in the field oozingfrom 2-3 week old perithecia in a cream tobright yellow, viscous droplet that clings to thetip of each perithecium. Spores discharged in171

this manner were presumably dispersed byrain-splashing.In histological studies of inoculated peanutstems, perithecia with a few nearly mature asciwere observed after 13 days and fully matureasci containing mature ascospores were commonlyobserved 2-3 weeks after inoculation.Ascospores were forcibly ejected from a singleperithecium for 2-3 weeks after maturity, priorto being exuded in a viscous ooze. Developmentand discharge of ascospores seemed tobe more closely related to water relations of thefungus than to temperature. Viability of ascosporeswas similar to conidia, i.e., they wereextremely sensitive to desiccation. The mostlikely role of ascospores in CBR epidemiologywas suggested to be short-distance, within-fieldspread of the disease.C. crotalariae was shown to producemicrosclerotia (average size = 53 x 88 µm)abundantly in decaying peanut tissue. Microsclerotia(ms) first appeared in infected roots55 days after inoculation in the field and numbersincreased rapidly after 90 days (Rowe et al.1974); Microsclerotia formed within CBR-infectedpeanut roots were shown to be effectivelong term survival propagules. As disintegrationof root tissues progresses, the propagulesare released into the soil, and spread locallyduring tillage and aqueous runoff (Krigsvold etal. 1977). Aerial dissemination of ms of C.crotalariae in windblown plant parts was observed.Root fragments containing ms werefound in debris expelled from peanut combinesoperating in infested fields in North Carolina.Fragments large enough to carry microsclerotiawere trapped 225 m downwind from combineson relatively calm days. Although it was consideredunlikely that airborne ms could explainthe apparent rapid spread of CBR across thesoutheastern United States, once the fungushas become established in a locality, airbornems could be effective in regional dispersal.Infection ProcessEarly stages of pathogenesis of peanut by C.crotalariae involved the formation of infectioncushions on the epidermis, followed by completehyphal colonization of the cortex(Johnston and Beute 1975). Collapse of theepidermal cells beneath infection cushions andnecrosis of surrounding cortical cells appearedto be a prerequisite for fungal invasion,suggesting the possible involvement of phytotoxins.Natural periderm formation appeared toeffectively limit C. crotalariae growth to thecortex under certain circumstances and plantswith only cortical decay were capable of recovery.A histological study on the nature of resistanceto CBR in peanut germplasm suggestedthe involvement of efficient formation of additionaleffective periderms in the resistancemechanism(s). Susceptible peanut cultivarssustained more breachments of the originalperiderm per length of taproot tissue than didresistant lines. Susceptible cultivars were alsoless efficient in formation of additional(walling-off) periderms than resistant lines, andthe additional periderms were ultimately lesseffective. Resistant lines were observed toinitiate phellogen in the pith and essentiallyslough an entire quadrant of infected taproot.Emerging fibrous roots disrupted the protectiveperiderm cylinder of the peanut taproot andprovided favorable infection courts of the fungus.Primary branch roots of resistantgenotypes were capable of periderm formationwhen infected by C. crotalariae. No peridermwas observed in fibrous roots of susceptiblecultivars. Microsclerotia were found only in thecortex of necrotic taproot and fibrous roots.Host RengeAll legumes tested to date appear to be hosts forC crotalariae (Mesonou 1973). A partial list ofsusceptible hosts included peanut, clover, alfalfa,Crotalaria, soybean, lupine, bean, andpea. Considerable variability in susceptibilitywas reported to exist between host species, e.g.soybean was much more resistant to C.crotalariae than was peanut. Certain nonleguminouscrops (tobacco and cotton) normallyincluded in peanut rotations in NorthCarolina have also been shown to be susceptibleto C. crotalariae when grown in fumigatedsoil in greenhouse tests (Rowe and Beute 1973),but no increase in inoculum occurred underfield conditions (Phipps and Beute 1979). Cornand small grains appeared highly resistant to C.crotalariae and should be useful as rotationalcrops in infested fields to minimize inoculumincrease (Phipps and Beute 1979; Rowe andBeute 1973).172

Inoculum QuantificationTechniquesIsolation ProcedureDevelopment of a semi-selective isolationmedium was essential for the study of theecology of soilborne pathogens. Repeated attemptsto quantify ms from peanut soil usingprocedure and medium reported for quantitativeisolation of other Cylindrocladium specieswere unsuccessful. Phipps et al. (1976) developedthe following medium for use with theelutriation procedure described below:Basal constituents of the isolation mediumincluded glucose, 15 g; yeast extract, 0.5 g;KNOa, 0.5 g; KH2PO4,1.0g;MgSC

esulted in infested, dry soil. Biopsied tissuesfrom plants indicated that more root infectionby C crotalariae occurred in infested, wet soil atall temperatures. In experiments usingnaturally-infested field soil (1.1 to 2.0 ms/g soil)disease severity was similar to that observed inartificially infested soil. Root rot was mostsevere in wet soil at 25°C. At each temperature,root rot was less severe in dry soil. It wasobserved in North Carolina that high rainfallearly in the growing season was necessary forsevere root rot since most peanut field soils arewell drained and sandy in texture. A subsequentperiod of moisture stress was thought to enhancethe expression of above groundsymptoms due to the absence or limitednumber of functional roots after infection androot rot.The survival of C. crotalariae ms in soil did notappear to be affected by moisture or temperatureduring the growing season (Phipps andBeute 1979). Incubation of soil samples in Virginiaat temperatures simulating winter conditions(6°C), however, decreased germinabilityof C. crotalariae ms (Roth et al. 1979). Incubationof naturally-infested soil under field conditionsfrom October to February (1978) indicated that asimilar low-temperature-induced phenomenonexists in nature. When soil samples were transferredto 26°C for 4 weeks, the low temperatureeffect was partially reversed.Population DynamicsMicrosclerotia were considered to be primarysurvival propagules for C. crotalariae in fieldsoil. Development of semi-selective media withutilization of wet sieving and/or elutriationtechniques for extraction of ms from soil providedthe opportunity for enumeration of populationsof C. crotalariae in soil over time andcropping sequence. Fallow soil, nonhost rotationalcrops and CBR-resistant peanutgermplasm were compared with susceptiblepeanut cultivars for effect on ms populations infield plots.Only slight reductions in ms densities weredetected in fallow soil and soil planted tononhost crops each year over two years testing(Phipps and Beute 1979). Incorporation of cropresidues (both host and nonhost) in soil afterharvest did not change ms densities after 5months. After one growing season, populationsof ms at harvest were 9.6, 5.2, and 1.6 timespreplant densities in soils planted to the CBRsusceptiblecultivar Florigiant, CBR-resistantArgentine and NC 3033, respectively. Microsclerotiadensities increased 3.7 times in soilplanted to soybean.Disease severity in the field was shown toreflect sensitivity of susceptible and resistantpeanut cultivars to inoculum densities of C.crotalariae ms in soil (Phipps and Beute 1977).CBR-susceptible cultivars were severely diseasedin soils having 0.5 ms/g soil or greaterinoculum densities if the environment wereconducive for infection. Resistant cultivars,however, grew and survived in soils having ashigh as 1000 ms/g soil. Resistant cultivars didsustain moderate to severe root rot and extensiveroot infection when inoculum densitieswere greater than 50 ms/g soil.Nematode InteractionsAlthough a precise relationship had been describedbetween inoculum density and diseaseseverity for both CBR susceptible and resistantpeanuts, response of peanut genotypes in infestedfields was frequently different from thatpredicted on the basis of ms densities.Nematode populations were shown to be amajor factor in modification of the diseaseincidence x inoculum density relationship.Sequential inoculation with nematodes andC. crotalariae increased CBR severity on bothCBR-susceptible (Florigiant) and CBR-resistant(NC 3033) peanuts in greenhouse tests. The ED 50values (microsclerotia/cm 3 soil to give 50%diseased plants) for Florigiant and NC 3033were decreased from 0.35 and 17.5, respectively,in fungus-only soil to 0.05 and 1.6, respectively,in soil containing Meloidogynehap/a (Northern root knot nematode) and thefungus. Two populations of root knot nematodeM. arenaria (Race 2) which do not reproduce onpeanut, also enhanced CBR on NC 3033 ingreenhouse tests. Correlations between populationsof M. hapla and C. crotalariae with CBRseverity weresignificant in field tests conductedfrom 1976-1978. In greenhouse tests the EDeovalues for Florigiant were decreased from 0.42in fungus-alone soil to 0.05 in soil containingMacroposthonia ornata (ring nematode). M.174

ornata reproduced on NC 3033 in similar testsbut did not enhance CBR severity on NC 3033. Inmicroplot tests in the field where M. ornata wasused in combination with C. crotalariae on bothcultivars, more diseased plants occurred withM. ornata + C. crotalariae than with eitherpathogen alone on Florigiant but not on NC3033, although the nematode reproduction factorwas higher on NC 3033 than on Florigiant.Fungal GeneticsEvaluation of peanut germplasm in field plotsover several years indicated that somegenotypes did not perform consistently at differentlocations (Wynne et al. 1975). Extremevariability in CBR severity under field conditionsand the prevalence of the sexual stage(perithecium) of C. crotalariae suggested thepossibility of physiological specialization in thefungus (Rowe and Beute 1975). All isolates ofthe fungus tested prior to 1974, regardless ofdiverse geographic origins, elicited the samegeneral pattern of host response on six peanutvarieties chosen to represent a range of CBRresistance. A wide range of virulence amongisolates did appear to be inherent in the fungus.This variability was not related to linear growthrate in culture nor was it correlated with geopraphicdistribution of the pathogen.A subsequent test was initiated to re-evaluatethe variability in virulence of C. crotalariaeisolates by using CBR resistant and susceptiblepeanut genotypes as host differentials to determinethe effect of resistant host plant selectionon degree of differential interactions betweenhost and pathogen isolates (Hadley et al.1979). The mean virulence of isolates of C.crotalariae from susceptible peanut cultivarsdid notdifferfrom that of isolates from resistantpeanuts when selection pressure was appliedonly for one growing season. Differences werenoted, however, among isolates from resistantpeanuts when ranked for virulence. Isolatesfrom the resistant peanuts showed the highestlevel of virulence on resistant peanut, but wereno more virulent on the susceptible peanut thanisolates originating from susceptible peanuts.According to a pathogen virulence model, isolatesoriginated from susceptible peanut hadabout eight times more general virulence thanspecific virulence. In only one cropping cycle ofCBR-resistant peanuts, specific virulence increasedfourfold in the previously nonselectedpathogen populations. It was suggested that apotential exists for change in fitness in C.crotalariae, even though corresponding resistancein the host appears to be quantitativelyinherited.A later experiment indicated that informationfor individual isolates may not be representativeof phenomenon in naturally occurringheterogenous fungus populations. Diseasereadings in the field for composites of isolates(chosen as specific for susceptible peanuts orspecific for resistant peanuts) suggested that aninteraction and/or recombination may be occurringamong composited isolates of C.crotalariae during the growing season.ReferencesBELL, D. K. 1967. Effects of soil temperature and plantage on the severity of Cylindrocladium rot of peanut.Plant Disease Reporter 51: 986-988.BELL, D. K., and SOBERS, E. K. 1966. A peg, pod, androot necrosis of peanuts caused by a species ofCalonectria. Phytopathology 56: 1361-1364.BEUTE, M. K., and ROWE, R. C. 1973. Studies on thebiology and control of Cylindrocladium black rot(CBR) of peanut. Journal of American Peanut Researchand Education Association 5: 197.BYRD, D. W., Jr., BARKER, K. R., FERRIS, H., NUSBAUM,C. J, GRIFFIN, W. E., SMALL,R. H., and STONE, C. A 1976.Two semi-automatic elutriators for extractingnematodes and certain fungi from soil. Journal ofNeonatology 8: 206-212.GARREN, K. H., BEUTE, M. K., and PORTER, E. M. 1972.The Cylindrocladium black rot of peanut in Virginiaand North Carolina. Journal of the American PeanutResearch and Education Association 4: 66-71.GARREN, K. H., PORTER, D. M„ and ALLISON, A. H. 1971.Cylindrocladium black rot of peanuts in Virginia.Plant Disease Reporter 55: 419-421.GRIFFIN, G. J. 1977. Improved selective medium forisolating Cylindrocladium crotalariae microsclerotlafrom naturally infested soils. Canadian Journal ofMicrobiology 23: 680-683.175

HADLEY, B. A., BEUTE, M. K., and LEONARD, K. J. 1979.Variability of Cylindrocladium crotalariae responseto resistant host plant selection pressure in peanut.Phytopathology 69: 1112-1114.JACKSON, C. R., and BELL, D. K. 1969. Diseases ofpeanut (groundnut) caused by fungi. University ofGeorgia Agricultural Experiment Station ResearchBulletin 56. 137 pp.JOHNSTON, S. A., and BEUTE, M. K. 1975. Histopathologyof Cylindrocladium black rot of peanut.Phytopathology 65: 649-653.KRIQSVOLD, D. T., and GRIFFIN, G. J. 1975. Quantitativeisolation of Cylindrocladium crotalariae microsclerotiafrom naturally-infested peanut and soybeanfield soils. Plant Disease Reporter 59: 543-546.KRIGSVOLD, D. T., GARREN, K. H., and GRIFFIN, G. J.,1977. Importance of peanut field cultivation andsoybean cropping in the spread of Cylindrocladiumcrotalariae within and among peanut fields. PlantDisease Reporter 61: 495-499.MISONOU, T. 1973. New black root rot disease in soybeansand peanuts caused by Calonectrlacrotalariae. Shokubutsu Boeki 27(2): 35-40.PHIPPS, P. M., and BEUTE, M. K. 1977. Influence of soiltemperature and moisture on the severity of Cylindrocladiumblack rot in peanut. Phytopathology67: 1104-1107.PHIPPS, P. M., and BEUTE, M. K. 1977. Sensitivity ofsusceptible and resistant peanut cultivars to inoculumdensities of Cylindrocladium crotalariaemicrosclerotia in soil. Plant Disease Reporter61: 300-303.PHIPPS, P. M., and BEUTE, M. K. 1979. Populationdynamics of Cylindrocladium crotalariae microsclerotiain naturally-infested soil. Phytopathology69: 240-243.PHIPPS, P. M., BEUTE, M. K., and BARKER, K. R. 1976. Anelutriation method for quantitative isolation ofCylindrocladium crotalariae microsclerotia fromPeanut field soil. Phytopathology 66: 1255-1259.ROTH, D. A., GRIFFIN, G. J., and GRAHAM, P. J. 1979. Lowtemperature induces decreased germinability ofCylindrocladium microsclerotia. Canadian Journalof Microbiology 25: 157-162.ROWE, R. C, and BEUTE, M. K. 1973. Susceptibility ofPeanut rotation crops (tobacco, cotton and corn) toCylindrocladium crotalariae. Plant Disease Reporter57: 1035-1039.ROWE, R. C, and BEUTE, M. K. 1975. Variability in virulenceof Cylindrocladium crotalariae isolates onPeanut. Phytopathology 65: 422-425.ROWE, R. C, and BEUTE, M. K. 1975. Ascospore formationand discharge by Calonectria crotalariae.Phytopathology 65: 393-398.ROWE, R. C, BEUTE, M. K., and WELLS, J. C. 1973.Cylindrocladium black rot of peanuts in NorthCarolina, 1972. Plant Disease Reporter57: 387-389.ROWE, R. C, BEUTE, M. K., WELLS, J. C, and WYNNE,J. C. 1974. Incidence and control of Cylindrocladiumblack rot of peanuts in North Carolina during 1973.Plant Disease Reporter 58: 348-352.ROWE, R. C, JOHNSTON, S. A., and BEUTE, M. K. 1974.Formation and dispersal of Cylindrocladiumcrotalariae microsclerotia in infected peanut roots.Phytopathology 64: 1294-1297.WYNNE, J. C, ROWE, R. C, and BEUTE, M. K. 1975.Resistance of peanut genotypes to Cylindrocladiumcrotalariae. Peanut Science 2: 54-56.176

Sclerotinia Blight of Groundnut — A Diseaseof Major Importance in the USAD. Morris Porter*A disease of the groundnut {Arachis hypogaeaL.) caused by a Sclerotinia sp was reported firstin Argentina in 1922 (Marchionatto 1922). In1933, Sclerotinia spp were reported attackinggroundnuts in China (Chu 1933) and in 1948 S.minor Jagger was the causal agent of a seriousgroundnut disease in Australia (Anon. 1948). Aroot and pod rot disease of groundnuts causedby S. minor and S. sclerotiorum (Lib.) de Barywas reported again in Argentina in 1960 (Frezzi1960). A wilt of peanut caused by S. miyabeanaHanzawa was reported in Taiwan in 1972 (Janand Wu 1972). Sclerotinia was observed first onpeanuts in the United States in 1971 (Porter andBeute 1974) and has since become widespreadin Virginia, North Carolina and Oklahoma. Infact, it is nowthe most serious disease problemin Virginia (Powell etal. 1976; Porter etal. 1977).Sclerotinia blight has not been observed inGeorgia, Florida, Texas or Alabama wheregroundnuts are grown commercially.SymptomsThe first symptom of Sclerotinia blight is usuallythe sudden wilting of a lateral branch of agroundnut plant (Porter and Beute 1974). Infectionof the main branch usually occurs by* Plant Pathologist, AR, SEA, U.S. Department ofAgriculture, Suffolk, Virginia 23437, USA.Cooperative investigations of Agricultural Research,Science and Education Administration,U.S. Department of Agriculture, and Research Division,Virginia Polytechnic Institute and State University,(VPI & SU). Contribution No. 414, Departmentof Plant Pathology and Plant Physiology, VPI& SU, Blacksburg, USA.This paper reports the results of research only.Mention of a pesticide in this paper does notconstitute a recommendation by the USDA nordoes it imply registration under FIFRA.growth of the fungus into the main branch froman infected lateral branch. The foliage on infectedbranches becomes chlorotic, turns darkbrown and withers, followed by death anddefoliation of that branch. These symptomsresult in a blight of the foliage characteristic ofSclerotinia disease (Fig.1-A). Once infection hasbeen initiated and environmental conditionsconducive to disease development persist,white, fluffy mycelium (Fig. 1-B) will develop onthe diseased tissue.The infection process appears to be bothintra- and inter-cellular with enzymatic activityconcentrating in the middle lamella, resulting intissue shredding. Shredding of the branch tissueis a characteristic sign of Sclerotinia blight(Fig. 1-C). Shredding of the peg tissue alsooccurs and results in severe pod shed (Fig. 1-D).Branch lesions are initially light tan and elongatedalong the axis of the branch (Fig. 2-D). Aslesions develop and age, they become dry anddark brown with a distinct demarcation zoneseparating infected and healthy tissue. Black,irregularly shaped sclerotia (0.02-3.0 mm) areproduced abundantly on the outside of allinfected groundnut plant parts including thebranches (Figs. 2-B, 2-D), pegs, and shells, andon the inside of branches, tap roots and underthe epidermal layers of the pods (Fig. 2-B) and inthe pod, both on the pod interface and on theseed (Porter and Beute 1974).Causal OrganismSpeciation of Sclerotinia usually is based in parton host range and size of sclerotia. Sclerotiniaspp including both small and large sclerotiumproducingisolates, attack a wide host range ofcrops (Abawi and Grogan 1979). The impracticalityof separating Sclerotinia species based onsclerotia! size was demonstrated by Purdy(1955) who showed thatthe small sclerotial type177

(S. minor), the intermediate sclerotial type (S.trifoliorum Eriks.) and the large sclerotial type(S. sclerotiorum) often produced sclerotia ofintermingling sizes among groups. Purdy,therefore, synonymized several species of S.sclerotiorum.In Virginia, the species of Sclerotiniapathogenic to groundnuts produced smallsclerotia ranging in size from 0.02-3.0 mmwhich were similar to those described by Jagger(1920). Both small and large sclerotiumproducingisolates of Sclerotinia were found ingroundnut fields where Sclerotinia was prevalentin Oklahoma (Wadsworth 1979). Apotheciaof S. minor and S. sclerotiorum have beenobserved in Oklahoma but not in Virginia andNorth Carolina. To resolve the taxonomic positionof the genus Sclerotinia, Kohn (1979) usedseveral taxonomic characters including the developmentof a free, discreet sclerotium, absenceof functional conidia, production of ascosporesand orientation of the cells in theoutermost layer of the apothecium to delineatethree species of Sclerotinia :-S. sclerotiorum, S.minor and S. trifoliorum. Using a neotypespecimen obtained from a diseased groundnutshowing symptoms of Sclerotinia blight in afield in Virginia in 1974, Kohn identified thecausal organism as S. minor.Disease Cycleand EpidemiologyInfection of groundnuts by S. minor is myceliogenic,that is, it originates from mycelia ofgerminating soil-borne sclerotia (Beute et al.1975; Wadsworth 1979). Sclerotinia minor usuallyinvades groundnut tissue includingbranches, leaflets and pegs at points of soilcontact. In Oklahoma, Wadsworth (1979) founda few infection sites some distance from soilcontact points and suggested the possibility ofascospore involvement in disease development.Under moist conditions defoliated groundnutleaflets or senescing leaflets still attached to theplant, but in contact with the soil, are easilycolonized by mycelia from germinatingsclerotia of S. minor. This food base enhancesdisease development but is not a necessaryprerequisite for infection since infection sitescommonly appear on branches in contact withthe soil but without the presence of such foodbases. For some diseases caused by Sclerotiniaspp a source of nutrition is a prerequisite forpenetration and infection of host tissue (Purdy1958). Volatile stimulants from remoistenedleaves greatly influenced the germination ofsclerotia of 5. minor over a wide pH range, withoptimum germination occurring at pH 6.5 (Hauet al. 1980).The incidence and severity of Sclerotiniablight can be detected by aerial infrared photography(Fig. 1-E). Sclerotinia blight ofgroundnut, characterized by a unique spectralsignature, can be detected on infrared imagerytaken at altitudes of about 20 000 meters, butlower altitudes (3500 meters) provided betterresolution for detailed study (Powell et al. 1976).The severity of Sclerotinia blight as detected ininfrared imagery can be correlated with actualpod losses in the field (Porter et al. 1977). Areason infrared photographs that were interpretedas slightly, moderately or severely damaged byS. minor, had groundnut pod losses due to thedisease which were 2, 5, and 7 times greater,respectively, than nondiseased areas. Inseverely damaged fields, groundnut losses dueto S. minor often exceed 50% of expected yield.Infection by most Sclerotinia species is generallydependent upon low temperatures (10-25°C) and high soil moisture (Abawi and Grogan1979). The severity of Sclerotinia blight ofgroundnuts in Virginia can be correlated withtemperature (D. M. Porter, unpublished data).The number of days the mean temperaturedropped to 21°C and below during July, Augustand September in Virginia was 23,13,26,12,18and 21, respectively, in 1974 through 1979.Sclerotinia blight was more severe in yearshaving the greater number of cool days. It wasmost severe in 1974 and 1976 and almost nil in1975. The disease was much widely spread in1976 than in 1974. Disease losses were minimalin 1977, but were severe in 1978 and 1979.Patterns of disease severity during each yearwere verified with infrared photography (Cobbet al. 1977).Mechanically injured groundnut foliage isvery susceptible to colonization by S. minor(Porter and Powell 1978). Groundnut plants,injured by tractor tires during pesticide application,were colonized by S. minor at twice thefrequency of noninjured plants. At one locationwhere Sclerotinia blight was severe, 152% in-178

Figure /. A, groundnut field exhibiting typical symptoms of Sclerotinia blight; B. characteristicwhite, fluffy mycelium growing on infected groundnuts; C. typical shreddingof plant tissue following colonization by S. minor; D, groundnut pods remaining insoil following harvest of plants severely infected with S. minor; and E, infraredphotograph showing distribution of symptoms of S. minor in a groundnut field(red color = healthy plants and gray color represents diseased areas).

crease in disease was noted in plants injured bytractor tires. Pod yield losses can also be correlatedwith plant injury. At two locations whereSclerotinia was severe, yields averaged 1736kg/ha in injured rows and 2658 kg/ha in noninjuredrows. Aerial infrared photographs readilyshow Sclerotinia blight in row middlesinjured by tractor tires (Fig. 2-A).From studies on the ecology and the survivalof sclerotia of S. minor it was found thatsclerotia are produced abundantly on infectedgroundnuts. Sclerotial populations, recoveredby sieving (Fig. 2-E), were 10 times greater insoil from severely infected areas of the fieldthan from slightly infected areas (Porter et al.1977). Sclerotia of S. minor can be observed ongroundnut debris 6 months following harvest(Fig. 2-B). At time of seeding, sclerotial countsmade from the top 2.5 cm of soil may be lessthan one sclerotia per 100 g soil (D. M. Porter,unpublished data). Immediately after harvestand following a severe infection by S. minor,sclerotial counts may exceed 50 sclerotia per100 g soil from the top 2.5 cm soil layer.Sclerotia can be recovered from thetop 20 cmof soil from fields having histories of Sclerotiniablight. Sclerotia of S. minor can survive in thesoil for several years. In a field having a historyof Sclerotinia blight, but planted to a nonhostcropforthreegrowing seasons, sclerotial populationsdeclined only slightly and sclerotia germinatedreadily.Many genera of fungi can be isolated fromsclerotia of S. minor. However, the mycoflora ofsurface-sterilized sclerotia is usually dominatedby species of Trichoderma which can be readilyobserved on the sclerotia in groundnut pods leftin the field following harvest.Sclerotinia minor can be transmitted by seed,but at a low frequency (D. M. Porter, unpublisheddata). Pods obtained from groundnutplants exhibiting severe symptoms ofSclerotinia blight were shelled, disinfected forthree minutes and plated on several media.After incubation for 14 days, S. minor grew fromless than 1% of the seed.Soybean {Glycine max L Merr.) plants aresusceptible to Sclerotinia spp. Both S. minorand S. sclerotiorum were isolated from diseasedsoybean plants growing in close proximityto groundnut fields (Phipps and Porter 1977).In greenhouse inoculation tests, both specieswere pathogenic to groundnuts. However, S.sclerotiorum has not been observed in Virginiabut has been observed in Oklahoma(Wadsworth 1979).ControlDifferences in susceptibility of 36 groundnutcultivars, breeding lines and plant introductionsto S. minor ranged from slight to severe (Porteret al. 1975). Florigiant, a cultivar currentlyplanted on over 90% of the groundnut acreagein Virginia and North Carolina, was the mosttolerant to S. minor of any cultivar tested. ANorth Carolina breeding line, 17165, and PI343392 were more tolerant than any of the otherlines tested. In a 3-year study under severedisease pressure in Virginia, PI 371521 and abreeding line, Virginia 71—347, were not immuneto S. minor but exhibited significantlyfewer symptoms of this disease than othercultivars, breeding lines and plant introductionsscreened (Coffelt and Porter 1980).Botran (2, 6-dichloro-4-nitroaniline) providedpartial control of Sclerotinia blight ingroundnuts in Virginia and North Carolina(Beute et al. 1975). Benomyl (methyl1-[butylcarbamoyl]-2-benzimidazolecarbamate),applied at high rates (4.48 and 6.62 kga.i./ha) provided some control of Sclerotiniablight (Porter 1977). Procymidone (3-[3,5-dichlorophenyl]-1, 5-dimethyl-3-azabicyclo[3.1.0]hexane-2,4-dione), a Dupontexperimental fungicide (DPX 4424) not registeredfor use on groundnuts and recently withdrawnfrom testing by the company, providedalmost complete control of Sclerotinia blight(Porter 1980b). Pod yields in plots treated withprocymidone (0.56 kg a.i./ha x four applicationsapplied directly to the groundnut foliageas a broadcast spray) averaged 4904 kg/hacompared to 2603 kg/ha in the untreated plots(Fig. 2-C). Fungicides closely related to procymidonesuch as Ridomil (methyl D, L-N-[2,6-dimethylphenyl]-N-[2-methoxyacetyl]-alaninate)and Rovral (1-isopropyl-carbamoyl-3[3-5dichlorophenyl] hydantoin) were not effectiveagainst Sclerotinia blight (Phipps 1980). The useof metham (sodium N-methyldithiocarbamate)applied in irrigation water for control ofSclerotinia blight was recently demonstrated(Krikun et al. 1980).Sclerotinia blight of groundnuts can be sup-181

pressed with dinitrophenol herbicides (Porterand Rud 1980). Oinoseb (2-sec-butyl-4,6-dinitrophenol) and naptalam (sodium N-1-naphthylphthalamate) + dinoseb applied broadcastat 0.84 kg/ha significantly reduced theseverity of Sclerotinia blight and increasedgroundnut yields. Crop value was increased byabout 18% in herbicide-treated plots.Plant nutrients such as zinc and coppersulfates applied to the groundnut foliage significantlysuppressed the development ofSclerotinia blight (Hallock and Porter 1979).These same nutrients applied to the soil had noeffect on disease suppression. Several otherplant nutrients, including N, K, Ca, Mg, P, Mn,Fe, B, S and CI, had little or no effect on disease.Some fungicides currently recommended asstandard production practices to controlleaf spot (Cercospora arachidicola Hori and Cercosporidiumpersonatum [Berk, and Curt.]Deighton) of groundnut enhance the severity ofSclerotinia blight. In fungicide screening testsconducted in Virginia in 1974, the severity ofSclerotinia blight was significantly greater inplots treated with chlorothalonil (tetrachloroisophthalonitrile)than in nontreatedplots (Beute et al. 1975). In later studies,chlorothalonil applied at rates recommendedfor leaf spot control not only increased theseverity of Sclerotinia blight but also significantlyreduced pod yield (Porter 1977). At otherfield locations, captafol (cis-N-[{1,1,2,2,-tetrachloroethyl} thio] 4-cyclohexene-1,2-dicarboximide), as well as chlorothalonil,enhanced the severity of Sclerotinia blightand significantly decreased pod yield (Porter1980a).At harvest, two and four times more plantsweredead in plots treated with chlorothalonil orcaptafol, respectively, than in untreated controlplots. Pod yields averaged about 500 kg/hagreater in untreated plots than in chlorothalonil,or captafol treated plots. Sclerotinia blight wassignificantly greater in all breeding lines, plantintroductions and cultivars treated withchlorothalonil than plants treated with benomyl(Coffelt and Porter 1980). Both fungicides wereused at rates recommended for leaf spotcontrol. The reason(s) for enhancementof Sclerotinia blight following usage ofchlorothalonil and captafol is not known. Thesoil microflora from plots treated withchlorothalonil and captafol was not differentfrom that obtained from nontreated plots(Lankow et al. 1980). In greenhouse-grownplants, inoculation with chlorothalonil-treatedinoculum enhanced the virulence of S. minor(M. K. Beute, personal communication). Oxalicacid production was over 2.5 times greater inmedium amended with chlorothalonil and captafolthan in similar nonamended media. Theincreased production of oxalic acid by S. minorfollowing application of either chlorothalonil orcaptafol may partially explain the enhancementof Sclerotinia blight under field conditionswhere these fungicides are utilized.ReferencesABAWI.G. S., and GROGAN.R.G. 1979. Epidemiology ofdiseases caused by Sclerotinia. Phytopathology69: 899-904.ANONYMOUS. 1948. Plant diseases. Notes contributedby the biological branch. Agricultural Gazette ofNew South Wales 59: 527-530.BEUTE, M. K., PORTER, D. M., and HADLEY, B. A. 1975.Sclerotinia blight of peanut in North Carolina andVirginia and its chemical control. Plant DiseaseReporter 59(9): 697-701.CHU, V. M. 1933. Notes on the presence of Sclerotiniamiyabeana in China, with special reference to thecomparison of this fungus with Sclerotiniaarachidis. 1932 Yearbook of the Bureau of Entomology,Hankow, China. (Review of Applied Mycology13: 615-616. 1934).COBB, P. R., POWELL, N. L, and PORTER, D. M. 1977.Survey of Sclerotinia sclerotiorum blight diseaselosses in peanut fields by remote sensing. Proceedingsof the American Peanut Research and EducationAssociation 9(1): 94.COFFELT, T. A., and PORTER, D. M. 1980. Screeningpeanuts iArachis hypogaea L.) for resistance toSclerotinia blight. Proceedings of the AmericanPeanut Research and Education Society 12.FREZZI, M. J. 1960. Enfermedades del mani el laprovincia de Cordoba (Argentina). Revista de InvestigacionesAgricolas 14: 113-155.HALLOCK, D. L, and PORTER, D. M. 1979. Nutrienteffects on Sclerotinia blight disease in peanuts.Proceedings of the American Peanut Research andEducation Society 11: 62.182

Figure 2. A. infrared photograph showing relationship of mechanical injury and subsequentcolonization of injured groundnut foliage by S. minor (note alternating bands ofred and gray representing healthy and diseased tissue, respectively); B. overwinteringof sclerotia of S. minor on groundnut debris; C. control of Sclerotiniablight of groundnut with experimental fungicide; D, typical stem lesions on groundnutscaused by S. minor; and E. sclerotia of S. minor on sieve.

HAU, F. C, BEUTE, M. K., and PORTER, D. M. 1980. Effectof soil pH and the presence of remoistened peanutleaves in germination oiSclerotinia minor sclerotia.Proceedings of the American Peanut Research andEducational Society 12: 32.JAGGER, I. C. 1920. Sclerotinia minor, n. sp, the causeof a decay of lettuce, celery, and other crops. Journalof Agricultural Research 20: 331-334.J A N , C. J., and Wu, L. C. 1972. Studies on peanut wilt inTaiwan. Memoirs of the College of Agriculture,National Taiwan University 13: 1-23.KOHN, L. M. 1979. A monographic revision of thegenus Sclerotinia. Mycotaxon 9: 365-444.KRIKUN, J., PAPAVIZAS, G. C, and FRANK, Z. 1980.Application of metham through sprinkler irrigationfor control of soilborne pathogens of peanuts. Proceedingsof the American Peanut Research andEducation Society 12: 42.LANKOW, R. K., PORTER, D. M, and GOUERT, J. R. 1980.The effect of fungicides on peanut field soil microflora.Proceedings of the American Peanut Researchand Education Society 12: 33.MARCHIONATTO, J. B. 1922. Peanut wilt in Argentina.Revista de la Facultad de Agronomia, UniversidadNacional de La Plata 3: 65-67.PHIPPS, P. M. 1980. Control of Sclerotinia blight inVirginia, Isle of Wight. Fungicide and nematicidetests 35: 212.PHIPPS, P. M., and PORTER, D. M. 1977. Sclerotiniablight of soybean in Virginia. Phytopathology69: 1042. (Abstr.)PORTER, D. M. 1977. The effect of chlorothalonil andbenomyl on the severity of Sclerotinia sclerotiorumblight of peanuts. Plant Disease Reporter61(12): 995-998.PORTER, D. M. 1980a. Increased severity of Sclerotiniablight in peanuts treated with captafol andchlorothalonil. Plant Disease 64: 394-395.PORTER, D. M. 1980b. Control of Sclerotinia blight ofpeanut with procymidone. Plant Disease 64.PORTER, D. M., and BEUTE, M. K. 1974. Sclerotiniablight of peanuts. Phytopathology 64(2): 263-264.PORTER, D. M., BEUTE, M. K., and WYNNE, J. C. 1975.Resistance of peanut germplasm to Sclerotiniasclerotiorum. Peanut Science 2(2): 78-80.PORTER, D. M., POWELL, N. L, and COBB, P. R. 1977.Severity of Sclerotinia minor blight of peanuts asdetected by infrared aerial photography. PeanutScience 4(2): 75-77.PORTER, D. M., and POWELL, N. L. 1978. Sclerotiniablight development of peanut vines injured bytractor tires. Peanut Science 5(2): 87-90.PORTER, D. M., and RUD, O. E. Suppression ofSclerotinia blight of peanuts with dinitrophenolherbicides. Phytopathology 70: (In press).POWELL, N. L, PORTER, D. M., and PETTRY, D. E. 1976.Use of aerial photography to detect diseases inpeanut fields. I. Sclerotinia blight. Peanut Science3(2): 21-24.PUROY, L. H. 1955. A broader concept of the speciesSclerotinia sclerotiorum based on variability.Phytopathology 45: 421-247.PURDY, L. H. 1958. Some factors affecting penetrationand infection by Sclerotinia sclerotiorum.Phytopathology 48: 605-609.WADSWORTH, D. F. 1979. Sclerotinia blight of peanutsin Oklahoma and occurrence of the sexual stage ofthe pathogen. Peanut Science 6: 77-79.185

Groundnut Foliar Disease in the United StatesD. H. Smith*Fungal DiseasesAlthough several groundnut foliar diseaseshave been reported in the United States, earlyand late leaf spot are the most widely distributedfoliardiseasesofgroundnuts. Theearly and lateleaf spot pathogens are seen primarily in theirimperfect states, i.e., as Cercosporaarachidicola Hori, and Cercosporidium personatum(Berk. & Curt.) Deighton. The perfectstates of both pathogens have been reported inthe United States, but there is no convincingevidence that ascospores are an importantsource of initial inoculum.Since 1976, there has been a gradual shiftfrom a predominantly early leaf spot populationto a substantial amount of late leaf spot in thesoutheastern United States (Smith and Littrell1980). A totally satisfactory explanation for thischange is not available, but some plausible explanationsare worthy of consideration.First, the groundnut crop has been harvestedlater in recent years, and this may have contributedto an increased inoculum potential of C.personatum. Second, the use of highly effectivefungicides for early leaf spot may have alteredthe leaf surface microflora, thereby providing acompetitive advantage for the late leaf spotfungus. Third, the extensive cultivation of onesusceptible cultivar (Florunner) in Alabama,Florida, and Georgia may have favored a shiftfrom early to late leaf spot. Other possible contributingfactors include nutrient status of thecrop, drought stress, previous crop sequence,increased use of irrigation in groundnut production,and unsatisfactory fungicide applicationschedules and methods of application.The shift in the relative abundance of earlyand late leaf spot is not a new phenomenon.During a 5-year period in the late 1920's and* Associate Professor, Texas A&M University, TexasAgricultural Experiment Station, Plant Disease ResearchStation, Yoakum, Texas 77995, USA.early 1930's in Georgia, Woodruff (1933) reportedthat early leaf spot contributed to severedefoliation during only two of five years. A fewyears later, again in Georgia, Jenkins (1938)reported that early leaf spot reached epidemicproportions in August and early September,whereas late leaf spot was most destructivefrom September through harvest. Late leaf spotwas of minor importance in Georgia from1967-1976 (Smith and Littrell 1980). In 1947,Miller (1953) collected groundnut leaves fromten southern states, and he reported that82% of the lesions were caused by C. arachidicola.During the 1979 growing season,the incidence of early and late leaf spot wasmonitored in a small-plot field test in Georgia.Late leaf spot was not observed until the secondweek in July, but by the end of the season morethan 99% of the lesions were those of C. personatum(Smith and Littrell 1980).Groundnut rust, caused by Puccinia arachidisSpegazzini, occurs annually in the groundnutproducing areas of southern Texas. Groundnutrust has been observed in all the groundnutproducing states, but the onset of rust is usuallylate in the season. Therefore, with the exceptionof southern Texas, rust does not usually contributeto groundnut crop losses.Only the uredial state of P. arachidis has beenobserved in United States, and the fungus doesnot survive during the intercrop period. Airborneuredospores are introduced annuallyfrom outside of the United States (Van Arsdel1972). Harrison (1972) observed groundnut rustin southern Texas during the first week of Julyin 1971. This is probably the earliest thatgroundnut rust has ever been observed in theUnited States. During 1971, rust reachedepidemic proportions in southern Texas (Harrison1972). During the same growing season,Thompson and Smith (1972) reported rust in 24groundnut producing counties in Georgia.Web blotch, caused by Phoma arachidicola,Marasas, Pauer & Boerema was first reportedin Texas during the 1972 growing season (Pettit186

et al. 1973). However, the fungus was presentin groundnut hay which was producedin Florida during the 1971 crop year(Smith, unpublished). Since then, web blotchhas been observed in several states, butepidemics of web blotch have been limited toTexas and Oklahoma. During recent years theincidence of web blotch has been diminishing inthe United States. We believe this is at leastpartially associated with the decreasing amountof highly susceptible Spanish type cultivars andan increasing amount of Florunner, a cultivarwith moderate resistance to web blotch (Smithet al. 1979). Both the perfect and the imperfectstates of the web blotch fungus have beenreported in the United States (Philley 1975).Leptosphaerulina crassiasca (Sechet)Jackson & Bell is a ubiquitous fungus in thegroundnut producing areas of the UnitedStates, but it is usually a minor foliar pathogen.In contrast with the early and late leaf spot fungi,only the perfect state of L crassiasca is knownto plant pathologists. L. crassiasca producestwo distinct symptoms, i.e., pepper spots andwedge-shaped leaf scorch symptoms. Frequently,leaf scorch symptoms are accompaniedby early or late leafspot lesions at or nearthe midvein in the scorched portion of the leaf,indicating that L crassiasca may be only asecondary invader of the leaflet. Smith andCrosby (1973) studied the aerobiology of Leptosphaerulinacrassiasca. They reported thatlarge numbers of L crassiasca ascospores weretrapped within 1-4 hours after sunrise, when airtemperature was rising and foliage was dryingon days without rain. On days with rain, concentrationsof L. crassiasca ascospores increasedrapidly with the onset of rainfall.Mercer (1977) reported L trifolii as a foliarpathogen of groundnuts in Malawi, but we areunaware of any reports of L trifolii as agroundnut foliar pathogen in the United States.Phyllosticta leaf spot, a minor foliar disease ofgroundnuts, has been reported in Georgia(Jackson and Bell 1969), and we have observeda low incidence of this leafspot disease in Texaseach year. Jackson and Bell observed the diseaseearly in the growing season, but we haveobserved it throughout most of the growingseason. We have frequently been able to findPhyllosticta sp in groundnut fields infested withjohnsongrass. On the basis of similarsymptoms on johnsongrass, we think that thisgrass may be a host for the Phyllosticta sp thatinvades groundnut foliage. However, cross inoculationstudies have not been conducted.Several other minor fungal pathogens ofgroundnut foliage have been reported in theUnited States. Smith (1972) reported that Cristulariellapyramidalis caused a leaf spot diseaseof groundnuts in Georgia. Littrell (1974a) reportedthat a foliar blight of groundnuts inGeorgia was caused by Rhizoctonia solani.Jackson and Bell (1969) found that a species ofColletotrichum, closely related to C. dematium,was consistently associated with leaf scorchsymptoms, but their attempts to produce leafscorch symptoms with this Colletotrichum spwere not successful. Jackson and Bell (1969)reported that Phomopsis sp was usually associatedwith L crassiasca, Cercospora spp orColletotrichum cf dematium in marginal necroticleaflet lesions. We have isolated Alternariaspp from leaf scorch lesions, but inoculationshave been unsuccessful (Smith, unpublished).Virus DiseasesGroundnut mottle is the most widely distributedgroundnut virus in the United States.Kuhn (1965) published the first report ongroundnut mottle in the United States. Demskiet al. (1975) reported that groundnut mottlevirus occurred in all the major groundnut producingstates, i.e., Georgia, Florida, Alabama,Texas, Oklahoma, New Mexico, North Carolina,and Virginia.In Georgia the incidence of peanut mottlevirus varied from 1 to 79% (Paguio andKuhn 1974). Paguio and Kuhn conducted agroundnut mottle virus survey in 1973, and theyreported a crop loss greater than 12 dollarsper acre in 46% of the fields surveyed;moreover, the estimate of the Georgiagroundnut crop loss attributed to groundnutmottle virus was more than 11 milliondollars in 1973. Demski et al. (1975) reported alow incidence of groundnut mottle virus inTexas and Oklahoma, and they suggested thatthe appropriate aphid vectors may be absent inthese groundnut producing areas.Miller and Troutman (1966) observedgroundnut stunt in Virginia in 1964, and Cooper(1966) observed the disease during the sameyear. Epidemics of groundnut stunt developed187

in North Carolina and Virginia in 1965 and 1966(Cooper 1966; Hebert 1967; Miller and Troutman1966). Since then, groundnut stunt hasbeen a minor disease of groundnuts in theUnited States. Groundnut stunt has also beenreported in Alabama and Georgia (Rogers andMixon 1972; Kuhn 1971). In 1967, Choopanya(1968) found groundnut stunt virus in whiteclover throughout most of South Carolina.However, Choopanya did not find the disease inSouth Carolina groundnut fields.Spotted wilt of groundnuts was reported inTexas by Halliwell and Philley (1974). Since theirreport, this author has observed a few infectedplants in Texas each year, but there has been notendency for the disease to increase in Texas,and spotted wilt has not been reported in othergroundnut producing states.Physiological DisordersVarious types of foliar symptoms are occasionallyobserved on groundnuts in the UnitedStates. In Texas and Oklahoma a symptomdescribed as atmospheric scorch (Home 1974)is probably caused either totally or partially byozone. The first evidence of ozone injury is aslight burn on the adaxial leaf surface, and thisprogresses to a dark brown scorched area. Cellsof the upper epidermis are usually most affected,but injury sometimes proceeds rapidlywhen secondary organisms invade the damagedtissue. Spanish market type peanuts aregenerally more susceptible than runner markettypes. Davis and Smith (1976) compared thereaction of ten groundnut cultivars to ozoneunder controlled conditions. Severity ratingsranged from O to 83.5, with Valencia A being mostsusceptible to ozone damage in contrast with aseverity rating of 0.5 for Florunner.Variegated leaves resulting from a geneticabnormality are occasionally observed. Thereseems to be a slightly higher incidence of this inSpanish market types, but we have also observedthis variegated symptom on Florunner.Various kinds of foliar symptoms induced bypesticides have been observed. Sometimesthese symptoms closely resemble Cercosporaleaf spot. In questionable instances we incubateleaves on moist filter paper to induce sporulation.The absence of sporulation providescircumstantial evidence that the symptomis associated with phytotoxicity instead ofCercospora leaf spot.Managementof Fungal Diseasesof Groundnut FoliageSeveral crop management practices reduce theamount of inititial inoculum. Burial of cropresidue with a moldboard plow is especiallyimportant when crop rotation is not part of thecrop management system. Crop rotation iseffective for reducing the inoculum potential ofboth soil-borne fungal and nematode pathogens.In addition, when groundnuts are plantedon land that has not been planted to peanuts forone or more years, the onset and rate of diseaseprogress for early and late leaf spot are delayedas contrasted with disease progress in a programof continuous groundnut culture.In the groundnut producing area of southernTexas, growers can avoid the impact ofgroundnut rust epidemics by plantinggroundnuts in early March. Since rust has neverbeen observed prior to the first week in July insouthern Texas, a crop planted in early March isusually exposed to rust for less than a monthprior to harvest. Therefore, crop losses attributableto rust are avoided by early planting. Inaddition, fewer fungicide applications are requiredfor management of early and lateleaf spot when groundnuts are planted in earlyMarch.In southern Texas the groundnut plantingseason ranges from early March to mid-July.Because inoculum concentration increases asthe season progresses, foliar diseases are partiallymanaged by planting successively latergroundnut crops in fields that are not adjacentto previously planted groundnut fields and notlocated in the direction of prevailing winds. Thedirection of prevailing wind is extremely relevantto the development of rust epidemics,because uredospores are well adapted to longdistance dispersal.FungicidesManagement of foliar diseases with fungicidesis a routine crop management practice in theUnited States. Prior to 1971, dust formulationsof copper, sulfur, and copper plus sulfur were188

outinely used for suppression of foliar diseases.However, after the introduction of benomyl,chlorothalonil, and fentin hydroxidethere was a rapid transition from dusting tospraying.Chlorothalonil is the most widely used fungicidefor management of groundnut foliardiseases in the United States. It is effectiveagainst early leaf spot, late leaf spot, rust, andweb blotch. Benomyl, captafol, copper ammoniumcarbonate, copper hydroxide, fentinhydroxide, mancozeb, maneb, and sulfur arecurrently registered for use in managing one ormore foliar diseases of groundnuts in theUnited States.Thefirstfungicideapplication is usually madewithin 30-40 days after planting, with subsequentapplications at intervals of 10-14 daysuntil 14-21 days prior to the anticipated date ofharvest. Fungicides are currently applied withvarious kinds of tractor propelled sprayers,fixed-wing aircraft, and sprinkler irrigation systems.Fungicide ToleranceBenomyl-tolerant strains of C. arachidicola andC. personatum developed in the southeasternUnited States after three years of extensive useof benomyl for control of groundnut foliardiseases (Clark et al. 1974; Littrell 1974b).Groundnut crop losses were probably avertedby changing to the use of protectant fungicidesin 1974.Smith et al. (1978) reported benomyl-tolerantstrains of C. arachidicola and C. personatum atone research station in Texas. They attributedthe development of tolerant strains to the annualevaluation of benomyl-alone foliar spraysin small plot field tests since 1967 and thesubsequent selection pressure for the developmentof benomyl-tolerant strains of C.arachidicola and C. personatum. There are noreports of the benomyl-tolerant strains of C.arachidicola and C. personatum strains in Texasgrower fields. A plausible explanation for thisfact is that Texas growers have not extensivelyused benomyl alone because of its ineffectivenessagainst rust and web blotch.Smith and Searcy (1975) tested 57 isolates ofC. arachidicola from 11 states and 5 foreigncountries for benomyl tolerance. All isolateswere collected prior to the use of benomyl, andno tolerant strains were found. In addition, wehave monitored a groundnut field where nofungicides are used and no benomyl-tolerantstrains of C. arachidicola have been isolated(Smith, unpublished). On the basis of the previouscircumstantial evidence, it appears that theincidence of benomyl-tolerant strains of C.arachidicola is probably very low or absentprior to the intensive use of benomyl.Some effects of fungicides on nontarget organismshave been reported. Backman et al.(1975) observed a consistently higher level ofSclerotium rolfsii Sacc. when Florunner foliagewas sprayed with benomyl. Porter (1980) reportedthat foliar sprays of captafol andchlorothalonil increased the severity ofSclerotinia blight on VA 72 R groundnuts.Campbell (1978) reported that foliar sprays ofeither fentin hydroxide or copper ammoniumcarbonate suppressed populations of the twospottedspider mite. Backman et al. (1977)reported that Guazatine Triacetate, a fungicidewith efficacy against Cercospora leaf spot, repelledlepidopterous larvae.Research on resistance to early and lateleaf spot has been accelerated in recent years(Abdou et al. 1974; Sowell et al. 1976; Hassanand Beute, 1977; Sharief et al. 1978; Kornegayet al. 1980). Sources of rust resistance havebeen reported (Bromfield and Cevario 1970;Hammons 1977; Subrahmanyam et al. 1980).Smith et al. (1979) reported some sources ofweb blotch resistance. Porter et al. (1971)evaluated breeding lines and cultivarsfor resistanceto pepper spot and leaf scorch under fieldconditions. However, in spite of the increasedemphasis on resistance to fungal diseases ofpeanut foliage, there are currently no agronomicallyacceptable cultivars with adequate resistanceto eliminate the use of fungicides formanagement of the principal foliar diseases ofgroundnuts.Management of Virus Diseasesof Groundnuts in the UnitedStatesThere is no satisfactory control measure forgroundnut mottle virus. Since the symptomsare frequently inconspicuous, growers areoften unaware of this disease in their fields.Kuhn et al. (1968) found no immunity to PMV189

when they screened 37 peanut cultivars and 428plant introductions in the greenhouse. Screeningwas done by mechanical inoculatinggroundnut plants and then subinoculatingPhaseolus vulgaris Topcrop' a local lesion host.In a 1978 report, Kuhn et al. indicated that PI261945 and PI 261946 were tolerant, becauseinfection did not reduce pod yield.The production of groundnut mottle virusfreeseed is a potential control measure. Demskiet al. (1975) reported a low incidence ofgroundnut mottle in Texas and Oklahoma, andthey suggested that these may be good locationsfor groundnut mottle virus-free seed production,probably because of the absence orpaucity of aphid vectors in that area.Kuhn and Demski (1975) discussed the possibilityof controlling groundnut mottle by insecticidalcontrol of aphid vectors. However, theywere doubtful about the practicality of thisstrategy because the groundnut mottle virus istransmitted in a stylet borne fashion. The virusis acquired with one probe into an infectedepidermal cell. Therefore, the virus can betransmitted immediately and only for a shortperiod of time. It is also probable that the firstaphids arrive from outside of the groundnut fieldand thus cannot be easily eliminated prior toacquiring the virus from infected groundnutplants that originated from infected seed.Tolin et al. (1970) reported that the incidenceof groundnut stunt was reduced whengroundnut fields were isolated from whiteclover. Culp and Troutman (1968) rated severalhundred A hypogaea cultivars, breeding lines,and introductions for their reaction togroundnut stunt. No immunity was reported,but symptoms were less severe on severalentries. Because of the low incidence ofgroundnut stunt in the United States there is noactive interest in the development of controlmeasures.Since spotted wilt is a minor groundnut diseasein only one groundnut producing state, noefforts have been made to develop controlmeasures. The possibility of disease resistanceis being considered by Ghanekar et al. (1979) atICRISAT.Future Research PrioritiesBecause of the increasing costs of purchasingand applying fungicides for management offoliar diseases in the United States, there is aneed for new cultivars with multiple foliar diseaseresistant, high yielding, good quality, andearly maturing traits. Rapid techniques forscreening large numbers of genotypes forresistance should be developed.Additional information on the epidemiologyof individual foliar pathogens and interactionsamong foliar pathogens will be useful in thedevelopment of new foliar disease managementstrategies. A thorough study of the ecologyof the non-pathogenic microflora of thegroundnut leaf surface may shed new light onour knowledge of the epidemiology of foliarpathogens.There seems to be a growing sense ofoptimism that new groundnut cultivars withmultiple pest resistance can be developed. Theattainment of this objective will be a majorachievement in the area of groundnut cropimprovement.ReferencesABDOU, Y. A. M., GREGORY, W. C, and COOPER, W. E.1974. Sources and nature of resistance to Cercosporaarachidicola Hori and Cercosporidium personatum(B. & C.) Deighton in Arachis species.Peanut Science 1:6-11.BACKMAN, P. A., RODRIGUEZ-KABANA, R., and WILLIAMS,J. C. 1975. The effect of peanut leaf spot fungicideson the non-target organism, Sclerotium rolfsiiPhytopathology 65: 773-776.BACKMAN, P. A., RODRIGUEZ-KABANA, R., HAMMOND,J. M., CLARK, E. M., LYLE, J. A., IVEY, H. W., and STAR-LING, J. -G. 1977. Peanut leaf spot research inAlabama. Auburn University Bulletin 489. 38 pp.BROMFIELD, K. R., and CEVARIO, S. J. 1970. Greenhousescreening of peanut (Arachis hypogaea) for resistanceto peanut rust (fuccinia arachidis). Plant DiseaseReporter 54: 381-383.CAMPBELL, W. V. 1978. Effect of pesticide interactionson the twospotted spider mite on peanuts. PeanutScience 5: 83-86.CHOOPANYA, DUANGCHI. 1968. Distribution of peanutstunt virus in white clover in South Carolina and itsrelationship to peanut culture. Plant Disease Reporter52: 926-928.190

CLARK, E., BACKMAN, P. A., and RODRIGUEZ-KABANA, R.1974. Cercospora and Cercosporidium tolerance tobenomyl and related fungicides in Alabama peanutfields. Phytopathology 64: 1476-1477.COOPER, W. E. 1966. A destructive disease of peanut.Plant Disease Reporter 50: 136.CULP, T. W., and TROUTMAN, J. L. 1968. Varietal reactionof peanuts, Arachis hypogaea, to stunt virus.Plant Disease Reporter 52: 914-918.DAVIS, D. D., and SMITH, D. H. 1976. Susceptibility ofpeanut varieties to ozone. Proceedings of theAmerican Peanut Research and Education Association8: 93. (Abs.).DEMSKI, J. W., SMITH, D. H„ and KUHN, C. W. 1975.Incidence and distribution of peanut mottle virus inpeanut in the United States. Peanut Science 2:91-93.GHANEKAR, A. M., REDDY, D. V. R., IIZUKA, N., A M I N .P. W., and GIBBONS, R. W. 1979. Bud necrosis ofgroundnut {Arachis hypogaea) in India caused bytomato spotted wilt virus. Annals of Applied Biology93: 173-179.HALUWELL, R. S., and PHILLEY, G. L. 1974. Spotted wiltof peanut in Texas. Plant Disease Reporter 58:23-25.HAMMONS, R. O. 1977. Groundnut rust in the UnitedStates and the Caribbean. PANS 23: 300-304.HARRISON, A. L. 1972. Observations on the developmentand spread of peanut rust in South Texas in1971. Plant Disease Reporter 56: 873-874.HASSAN, H. N., and BEUTE, M. K. 1977. Evaluation ofresistance to Cercospora leafspot in peanutgermplasm potentially useful in a breeding program.Peanut Science 4: 78-83.HEBERT, T. T. 1967. Epidemiology of the peanut stuntvirus in North Carolina. Phytopathology 52: 1513-1516.HORNE, C. W. 1974. Peanut disease atlas. Texas AgriculturalExtension Service, Texas A&M University,Texas, USA. MP-1170. 15 pp.JACKSON, C. R., and BELL, D. K. 1969. Diseases ofpeanut (groundnut) caused by fungi. University ofGeorgia College of Agriculture, Experiment StationResearch Bulletin 56. 137 pp.JENKINS, W. A. 1938. Two fungi causing leaf spot ofpeanut. Journal of Agricultural Science 56: 317-332.KORNEGAY, JULIA L, BEUTE, M. K., and WYNNE, J. C.1980. Inheritance of resistance to Cercosporaarachidicola and Cercosporidium personatum in sixVirginia-type peanut lines. Peanut Science 7: 4 - 9 .KUHN, C. W. 1965. Symptomatology, host range, andeffect on yield of a seed transmitted peanut virus.Phytopathology 55: 880-884.KUHN, C. W. 1971. Peanut stunt virus in Georgia. PlantDisease Reporter. 55: 453.KUHN, C. W., and DEMSKI, J. W. 1975. The relationshipof peanut mottle virus to peanut production. Universityof Georgia Agricultural Experiment StationResearch Report 213. 19 pp.KUHN, C. W., GROVERSOWELL, Jr., CHALKLEY, J. H., andSTUBBS, H. F. 1968. Screening for immunity topeanut mottle virus. Plant Disease Reporter 52:467-468.KUHN, C. W., PAGUIO, 0. R., and ADAMS, D. B. 1978.Tolerance in peanuts to peanut mottle virus. PlantDisease Reporter 62: 365-368.LITTRELL, R. H. 1974a. Rhizoctonia foliar blight ofpeanuts. Journal of the American Peanut Researchand Education Association 6: 62 (Abs.).LITTRELL, R. H. 1974b. Tolerance in Cercosporaarachidicola to benomyl and related fungicides.Phytopathology 64: 1377-1378.MERCER, P. C. 1977. Pests and diseases of groundnutsin Malawi. I. Virus and foliar diseases. Oleagineux32: 433-448.MILLER, L. I. 1953. Studies on the parasitism of Cercosporaarachidicola Hori and Cercospora personate(B. & C). Ell. & Ev. Ph.D. thesis. University ofMinnesota, St. Paul, USA. 120 pp.MILLER, L. I., and TROUTMAN, J. L. 1966. Stunt diseaseof peanuts in Virginia. Plant Disease Reporter 50:139-143.PAGUIO, 0. R., and K UHN, C. W. 1974. Survey for peanutmottle virus in peanut in Georgia. Plant Disease Reporter58: 107-110.PETTIT, R. E., RUTH ATABER., and HARRISON, A. L. 1973.Ascochyta web blotch of peanuts. Phytopathology63: 447. (Abs.).PHILLEY, G. L. 1975. Peanut web blotch: growth,pathogenesis and hosts of the causal agent, Mycosphaerellaargentinensis. Ph.D. thesis. Texas A&MCollege Station, Texas, USA. 116 pp.191

PORTER, D. M. 1980. Increased severity of Sclarotiniablight in peanuts treated with captafol andchlorothalonil. Plant Disease 64: 394-395.PORTER, D. M., GARREN, K. H„ MOZINGO, R. W., and VANSCHAIK, P. H. 1971. Susceptibility of peanuts toLeptosphaerulina crassiasca under field conditions.Plant Disease Reporter 55: 530-532.ROGERS, K. M., and MIXON, A. C. 1972. Peanut stuntvirus in Alabama. Plant Disease Reporter 56: 415.SHARIFF, Y., RAWLINGS, J. O., and G REGORY, W. C. 1978.Estimates of leaf spot resistance in three interspecifichybrids of Arachis. Euphytica 27: 7 4 1 -751.SMITH, D. H. 1972. Arachis hypogaea: a new host ofCristulariella pyramidalis. Plant Disease Reporter56: 796-797.SMITH, D. H., and CROSBY, F. L. 1973. Aerobiology oftwo peanut leaf spot fungi. Phytopathology63: 703-707.SMITH, D. H., and LITTRELL, R. H. 1980. Management ofpeanutfoliar diseases with fungicides. Plant Disease64: 356-361.SMITH, D. H., and SEARCY, J. W. 1975. Absence ofbenomyl tolerance in a collection of Cercosporaarachidicola isolates. Proceedings of the AmericanPhytopathological Society 2: 141. (Abs.).SMITH, D. H., MCGEE, R. E., and VESELY, L. K. 1978.Isolation of benomyl-tolerant strains of Cercosporaarachidicola and Cercosporidium personatum atone location in Texas. Proceedings of the AmericanPeanut Research and Education Association 10-67.(Abs.).SMITH, O. D., SMITH, D. H., and SIMPSON, C. E. 1979.Web blotch resistance in Arachis hypogaea. PeanutScience 6: 99-101.S O W E U , G., SMITH, D. H., and HAMMONS, R. 0. 1976.Resistance of peanut plant introductions to Cercosporaarachidicola. Plant Disease Reporter50: 494-498.SUBRAHMANYAM, P., GIBBONS, R. W., NIGAM, S. N., andRAO, V. R. 1980. Screening methods and furthersources of resistance to peanut rust. Peanut Science7: 10-12.THOMPSON, S. S., and SMITH, D. H. 1972. Distributionand significance of peanut rust in Georgia in 1971.Plant Disease Reporter 56: 290-293.TOLIN, S. A., ISAKSON, 0. W., and TROUTMAN, J. L. 1970.Association of white clover and aphids with peanutstunt virus in Virginia. Plant Disease Reporter54: 935-938.V A N ARSDEL, E. P., and HARRISON, A. L. 1972. Possibleorigin of peanut rust epidemics in Texas.Phytopathology 62: 794. (Abs.).WOOOROOF, N. C. 1933. Two leaf spots of the peanut{Arachis hypogaea L). Phytopathology 23: 627-640.192

Research on Fungal Diseases of Groundnutat ICRISATP. Subrahmanyam, V. K. Mehan,D. J. Nevill and D. McDonald*Many fungal diseases of groundnut are known(Jackson and Bell 1969; Garren and Jackson1973) and many fungi are reported to beclosely associated with groundnut fruits andseeds. Some of the diseases are of restricteddistribution but most are of common occurrencethroughout the Semi-Arid Tropics (SAT).At ICRISAT the main concern is with thosewidespread diseases that cause economicallyimportant losses in yield, and in this paperinvestigations carried out during the past 4years on important foliar and soilborne diseasesare briefly reviewed.Foliar DiseasesRust (Puccinia arachidis Speg.)Previously unimportant outside the Americas(Bromfield 1971), rust is now of economic importancein almost all groundnut growing areasof the world (Hammons 1977; Subrahmanyamet al. 1979). Yield losses from rust may besubstantial and damage is particularly severewhere the crop is attacked by both rust and thelonger established Mycosphaerella leaf spots.Investigations were carried out on the biologyof the rust fungus so as to determine whatfactors were likely to influence perpetuationand spread of the disease. Biological data werealso needed for development of methods forscreening germplasm for resistance to the disease.A wide range of crop and weed species werechecked for possible collateral hosts of rust butnone was found outside the genus Arachis.The uredial stage only of the rust has beenfound although constant examination wasmade of many germplasm lines and some wild* Pathologists, International intern, and PrincipalPlant Pathologist, respectively, Groundnut ImprovementProgram, ICRISAT.Arachis species at ICRISAT. Groundnut plantsfrom various parts of India have also beenexamined at every opportunity. Attempts toinduce teliospore formation by modification ofenvironmental factors were not successful. Itwas concluded that uredosporeswerethe main,if not the only, means of rust carry-over anddissemination in India.Laboratory experiments showed thaturedospores could be stored for long periods atlow temperature without loss of viability butthat at high temperatures, they rapidly lostviability. For instance, when stored at 40°C theylost viability within 5 days. Uredospores onexposed crop debris lost all viability within 4weeks under postharvest conditions atICRISAT. Pods and seeds from rust affectedcrops are commonly surface-contaminated withuredospores. Tests on uredospores taken fromsurface-contaminated seeds stored at roomtemperature showed viability to decrease froman original 95% to zero after 45 days. Implicationsfor disease carry-over and for plantquarantine are obvious. Rust is particularlysevere in South India where groundnuts aregrown in some areas at all times of the year.Light was found to inhibit uredospore germinationand germ-tube elongation, indicatingthat field inoculation might be more successfulif carried out in the evening rather than throughthe day.The presence of liquid water on the leafsurface was found to be necessary for uredosporegermination and infection.Preliminary rust resistance screening of theICRISAT germplasm collection (now over 8000entries) was carried out in the rainy seasons of1977, 1978 and 1979 under natural diseasepressure in the field. Infector rows and checkplots of the highly susceptible cv TMV-2 werearranged systematically throughout the trials.Entries which were rated between 1 and 5 on a9-point disease scale (where 1 = no rust, and9 = 50-100% offoliagedestroyed by rust) were193

selected for advanced field screening. This wasdone either in the rainy season as described orin the postrainy season w h e n artificial inoculationwith uredospores and overhead irrigationto maintain high humidity were required toensure good development of rust. Genotypesfound to show g o o d resistance to rust atICRISAT are listed in Table 1 together w i t h theirTable 1. Genotypes resistant to rust atICRISAT.GenotypeRust Score aNC Acc 170902.0PI 414332 2.0PI 405132 2.5PI 341879 2.5PI 393646 2.5NC Acc 17133-RF 3.0EC 76446 (292) 3.0PI 259747 3.0PI 350680 3.0PI 390593 3.0PI 381622 3.0PI 393643 3.0PI 407454 3.0PI 315608 3.0PI 215696 3.0PI 393641 3.0PI 314817 3.0PI 393517 3.0PI 414331 3.0PI 393527-B 3.0NC Acc 927 3.3PI 390595 3.5PI 393531 3.5NC Acc 17127 3.8PI 393526 4.0NC Acc 17129 4.0NC Acc 17132 4.0NC Acc 17135 4.0NC Acc 17124 4.0PI 298115 4.0PI 393516 4.5NC Acc 17142 5.0Krap Str 16 5.0TMV-2 b 9.0Robut 33-1* 9.0a. Rust score on 9-polnt disease scale.b. Standard susceptible cultivars.mean rust scores on the 9-point scale. Scoresfor t w o susceptible cultivars are included forcomparison.Wild Arachis species being g r o w n in the fieldin close juxtaposition w i t h severely rust affectedgroundnuts were examined at intervalsthrough the season for evidence of rust infection.Those species w h i c h showed no developmentof rust are listed in Table 2. Although rustdid not develop on Arachis stenocarpa, somenecrotic lesions were formed that may haveresulted f r o m arrested invasion by the pathogen.Using artificial inoculation, potted plants androoted detached leaves were used in screeningtrials in glasshouse and laboratory, respectively.The methods were effective in separatinggenotypes w i t h large differences in resistance,e.g., highly resistant as opposed to susceptible,but were not suitable for showing any intermediatereactions.In studies on components of resistance, it wasfound that neither size nor frequency of stomatawas correlated with resistance. Infection frequencywas lower in resistant than in susceptiblegenotypes and the incubation period waslonger. Irrespective of whether genotypes wereimmune, resistant, or susceptible, uredosporesgerminated on the leaf surface and germ-tubesentered the leaf via stomata. In i m m u n egenotypes, the germ-tubes died without furtherdevelopment. Differences in resistance weremanifest by differences in rate and degree ofdevelopment of the rust mycelium in the substomatalcavities and in invasion of leaf tissues.Table 2.Wild Arachis spp on which no rustdeveloped in the field despite heavydisease inoculum.Species PI Number Section SourceA. duranensis 219823 Arachis ArgentinaA. correntina 331194 Arachis ArgentinaA. cardenasii 262141 Arachis BoliviaA. chacoense 276235 Arachis ParaguayA. chacoense XA. cardenasii - F 1 hybrid USAA. pusilla 338448 Triseminalae BrazilA. sp 9667 262848 Rhizomatosae BrazilA. sp 10596 276233 Rhizomatosae Paraguay194

Mycosphaerella or "Carcospora"Leaf Spots (Early Leaf Spot -Cercospora arachldlcola Hori;Late Leaf Spot — Cercosporidiumpersonatum [Berk, and Curt.]Deighton)The Mycosphaerella leaf spots are probably themost important diseases of groundnuts on aworldwide scale. Both are commonly presentand their relative importance is determined bycrop and environmental factors. At ICRISAT, thedisease incited by C. personatum is of regularoccurrence and reaches high levels on rainyseason groundnuts but that incited by C.arachidicola is much less common and rarelyreaches levels high enough to permit fieldresistance screening.Field screening for resistance to the leaf spotswas carried out simultaneously with the rustscreening and a similar 9-point disease scalewas used. Entries rated between 1 and 5 wereselected for advanced field screening. All fieldscreening utilized natural inoculum. The diseasesdeveloped more rapidly and screeningwas more effective in the rainy season thanin the irrigated postrainy season crops.Genotypes found to have resistance to C. personatumat ICRISAT are listed in Table 3.Genotypes with field resistance to C. personatumwere further tested for resistance inglasshouse screening trials. Good correlationswere found between field and glasshouse testsin respect of defoliation, lesion size and sporulationindex. Laboratory screening in whichrooted detached leaves were inoculated with C.personatum also proved useful. The lattermethod was also useful in the study of resistancemechanisms.Both high resistance and immunity have beenfound among wild Arachis species (Table 4).The ICRISAT Groundnut Cytogeneticists haveproduced hybrids between some of the resistantwild species and the cultivated groundnut,and by backcrossing have obtained near tetraploidmaterial which is being tested at all stagesfor resistance to leaf spots and to rust.With leaf spots as with rust, germination ofspores and entry into the leaf via stomata didnot appear to be in any way inhibited in resistantgenotypes. Resistance was again manifestin the postentry phase.Table 3. Genotypes resistant to C. parsonatumat ICRISAT.GenotypeLeaf spot score*EC 76446 (292) 3.2NC Acc 17133-RF 3.3PI 259747 3.3PI 350680 3.3NC Acc 927 4.0NC Acc 17127 4.3Krap Str 16 4.3RMP-91 4.7NC Acc 17090 4.8NC Acc 17130 4.8NC Acc 17129 4.8NCAcc 17132 4.8NCAcc 17135 4.8NC Acc 17124 4.8RMP-12 5.0TMV-2 b 9.0«. Leaf spot score on 9-polnt disease scale.b. Standard susceptible cultlvar.Table 4. Wild Arachls spp — reaction to Carcospora arachidicola and Cercosporidium paraonatum.Reaction toSpecies PI Number C. arachidicola C. personatumA. chacoenseA. cardenasiiA. sp 10596A. stenosperma276325262141276233338280Highly resistantSusceptibleImmuneHighly resistantHighly resistantImmuneImmuneHighly resistant195

Yield Losses f r o m Rust and Leaf S p o t sa n d M u l t i p l e ResistanceRust and leaf spots normally occur together andit is difficult to allocate individual responsibilityfor the resulting damage to the crop. In the 1979rainy season we attempted to estimate yieldlosses by applying fungicides to susceptibleand disease resistant genotypes; Daconil tocontrol leaf spots and rust, Bavistin to controlonly leaf spots, and Calixin to control only rust.Loss estimates are shown in Table 5. Losseswere less in the resistant than in the susceptiblegenotypes.Comparison of Tables 1 and 3 will show thatsome of the genotypes resistant to rust are alsoresistant to C. personatum leaf spot. Also, somenew sources of resistance to both diseases haverecently been found in Federal Experiment ResearchStation — Puerto Rico (FESR) breedinglines (Table 6). These lines originated from anatural hybrid selected for resistance to rust inPuerto Rico by USDA scientists.Some of the resistant genotypes can outyieldestablished Indian cultivars when grown withoutprotective fungicide treatment at ICRISAT.Further work is required of breeders to incorporatehigher yields and better agronomic charactersinto the resistant materials.Other Foliar DiseasesSome preliminary investigations have beenmade on what are at present regarded as minorfoliar pathogens. These include diseases incitedby Leptosphaerulina crassiasca (Sechet)Table 5. Yield losses from rust and leaf spotsat ICRISAT.Mean percentage loss of podyield fromGenotype Leaf spots RustRobut 33-1 aPI 259747EC 76446 (292)NC Acc 1709059301018a. Standard auscaptlble cultivar.52231214Leaf spotsand rust70373029Table 6. Genotypes resistant to rust and laafspot — FESR lines tested at ICRISAT.Mean disease scores(9-point scale)Genotype Rust Leaf spotFESR 5-P2-B1 2.0 3.0FESR 5-P17-B1 2.0 3.0FESR 7-P13-B1 2.0 3.0FESR 9-P3-B1 2.0 3.0FESR 9-P4-B1 2.0 4.3FESR 9-P7-B1 2.7 3.3FESR 9-P7-B2 2.7 4.3FESR 9-P8-B2 2.0 3.0FESR 9-P12-B1 2.0 2.7FESR 11-P11-B2 2.3 2.7FESR 12-P4-B1 2.0 2.0FESR 12-P5-B1 2.0 2.7FESR 12-P6-B1 2.7 3.7FESR 12-P14-B1 2.0 3.3FESR 13-P12-B1 2.0 2.7TMV-2 a 9.0 9.0a. Standard susceptible cultivar.Jackson and Bell, Alternaria alternata (Fr.) Keissler,and Myrothecium roridum Tode ex. Fr.Soilborne DiseasesSeed and Seedling RotsSeed rots and seedling diseases of groundnutare of common occurrence in the SAT and maycause serious losses in yield. The diseases maydevelop from fungi already established in theseeds before sowing, or may result from directinvasion of seeds or seedlings by soil fungi.Many species of fungi have been reported tocause seed rots and several are known to causediseases of seedlings. Some fungi causing diseasesat ICRISAT are listed in Table 7.Two important diseases of groundnut seedlingsare Crown Rot which is caused by Aspergillusniger van Tiegh and Aflaroot which iscaused by toxigenic strains of Aspergillusflavus Link, ex Fr. Initial screening of theICRISAT germplasm collection has indicated196

Table 7. Fungi associated with seed andseedling diseases at ICRISAT.Aspergillus flavus Link, ex Fr.Aspergillus niger van Tiegh.Botryodiplodia theobromae Pat.Fusariurn sppMacrophomina phaseolina (Tassi) Goid.Penicillium sppRhizoctonia solani KuehnSclerotium rolfsii Sacc.that some genotypes may possess resistance tothese diseases.Pod RotPod rot diseases are widespread in the SAT andare known to cause severe damage in a numberof countries (Abdou and Khadr 1974; Frank1972; Mercer 1977; Porter et al. 1975). Highlevels of pod rot were observed in the 1978-79postrainy season crop at ICRISAT and screeningof germplasm for resistance was initiated.Some 2000 genotypes have now been screenedunder natural field disease conditions. Standardlocal cultivars had 20-25% of pods rottedwhile disease levels in germplasm lines rangedfrom 4 to 72%. Genotypes with pod rot scores of10% or lower were selected for advancedscreening in disease sick plots.The etiology of the disease is still beinginvestigated. Fungi commonly isolated fromrotted pods at ICRISAT are listed in Table 8.Table 8.Dominant speciesFungi Isolated from rotted pods aICRISAT.Fusarium solani (Mart.) Sacc.Fusarium oxysporum SchlechtSubdominant Macrophomina phaseolinaspecies(Tassi) Goid. Rhizoctoniasolani KuehnAssociate speciesAspergillus flavus Link, ex Fr.Aspergillus niger van Tiegh.Fusarium acuminatum Ell. & Ev.Fusarium equiseti (Corda) Sacc.Fusarium fusaroides(Frag. & Cif.) BoothGliocladium roseum Bain.Trichoderma viride Pers. ex Fr.The Aflatoxin ProblemContamination of groundnuts with afIatoxins isa serious problem in many parts of the SAT. Theubiquitous Aspergillus flavus which producesthese toxic and carcinogenic substances mayinvade groundnut seeds before harvest, duringpostharvest drying, and during storage if theseeds are wetted. From the continued appearanceof reports of aflatoxin contamination ofproduce it would appear that SAT farmers havenot adopted the crop handling and storagemethods designed to reduce aflatoxin contaminationin groundnuts. It has therefore becomenecessary to investigate the possibilities ofgenetic resistance in the hope of developingcultivars with pods or seeds which A. flavuscannot invade, or which if invaded, do notsupport aflatoxin production.Workers in the USA (Mixon and Rogers 1973;Bartz et al. 1978) have shown some genotypesto have high levels of resistance to A flavusinvasion and colonization of dry seeds. This dryseed resistance is dependent upon the testabeing entire and undamaged. The test is asimple one. Mature undamaged seeds thathave been dried and stored for several weeksare placed in a petri dish and hydrated to20-25% water content. A suspension of A.flavus spores is added to them, and they areincubated for about 8 days. The percentage ofseeds which are colonized by the fungus indicatesthe degree of dry seed resistance possessed.The ICRISAT germplasm collection is nowbeing screened. The reactions of threegenotypes reported resistant in the USA andsome Indian cultivars are given in Table 9.Table 9. Dry seed resistance to A. flavus colonization.GenotypePercentage of seeds colonizedby A. flavus anddisease testingResistant lines from USAUF 715137.0 ResistantPI 337394 F 9.1PI 337409 9.2Indian cultivarsJunagadh 11 11.6TMV-235.0 SusceptibleOG 43-4-196.0 Highly susceptible197

There is no evidence th at the genotypes so farfound with dry seed resistance have any specialdegree of resistance to invasion of pods orseeds before harvest or during postharvestdrying. Investigations have started into possibleresistance during these phases, and particularattention is being given to genotypes whichhave shown resistance to pod rots.Some early research (Tulpule 1967; Kulkarniet al. 1967) indicated that certain cultivars hadresistance to the production of aflatoxin. However,these findings were not confirmed byfurther research (Doupnik etal. 1969; Aujla et al.1978), although there were indications thatslight differences might exist between cultivarsin their ability to support aflatoxin production.In dry seed resistance testing at ICRISAT,toxigenic strains of A. flavus are used andgenotypes are being checked for possible differencesin efficiency, as substrates for anatoxinsproduction.Other S o i l b o m e DiseasesA number of soilbome diseases occur regularlyat ICRISAT but at low incidence. These includewilt and root rot caused by species of Fusarium;a black root rot caused by Macrophominaphaseolina (Tassi) Goid; a root rot caused byRhizoctonia solani Kuehn; and stem rot causedby Sclerotium rolfsii Sacc. Disease sick plots arebeing established to allow screening of thegermplasm collection for possible resistance tothese diseases.ReferencesABDOU, Y. A, and KHADR, A. S. 1974. Systemic controlof seedling and pod rot disease of peanut (Arachishypogaea L). Plant Disease Reporter 58: 176-179.AUJLA, S. S., CHOH AN, J. S., and M EHAN, V. K. 1978. Thescreening of peanut varieties for the accumulationof aflatoxin and their relative reaction to thetoxigenic isolate of Aspergillus flavus Link ex Fries.Punjab Agricultural University Journal of Research15: 400-403.BARTZ, J. A., NORDEN, A. J., LAPRADE, J. C, andDEMUYNK, T. J. 1978. Seed tolerance In peanuts[Arachis hypogaea L.) to members of the Aspergillusflavus group of fungi. Peanut Science 5: 53-56.DOUPNIK, B. 1969. Aflatoxins produced on peanutvarieties previously reported to inhibit production.Phytopathology 59: 1554.FRANK, Z. R. 1972. Notes on soil management inrelation to Pythium rot of peanut pods. Plant DiseaseReporter 56: 600-601.GARREN, K. H., and JACKSON, C. R. 1973. Peanutdiseases. Pages 429-494 in Peanuts-culture anduses. American Peanut Research and EducationAssociation, Inc. Stillwater, Oklahoma 74074, USA.HAMMONS, R. O. 1977. Groundnut rust in the UnitedStates and the Caribbean. Pest Articles and NewsSummaries 23: 300-304.JACKSON, C. R., and BELL, D. K. 1969. Diseases ofpeanut (groundnut) caused by fungi. University ofGeorgia, College of Agriculture Experiment StationResearch Bulletin 56.KULKARNI, L. G., SHARIEF, Y., and SARMA, V. S. 1967.Asiriya Mwitunde' groundnut gives good results atHyderabad. Indian Farming 17: 11-12.MERCER, P. C. 1977. A pod rot of peanuts in Malawi.Plant Disease Reporter 61: 51-55.MIXON, A. C, and ROGERS, K. M. 1973. Peanut accessionsresistant to seed infection by Aspergillusflavus. Agronomy Journal 65: 560-562.PORTER, D. M., GARREN, K. H., and VAN SCHAIK, P. H.1975. Pod breakdown resistance in peanuts. PeanutScience 2: 15-18.RAO, K. S., and TULPULE, P. G. 1967. Varietal differencesof groundnut in the production of aflatoxin. Nature214: 738-739.SUBRAHMANYAM, P., REDDY, D. V. R., GlBBONS, R. W.,RAO, V. R., and GARREN, K. H. 1979. Current distributionof groundnut rust in India. Pest Articles andNews Summaries 25: 25-29.198

Studies of Resistance to Foliar PathogensD. J. Nevill*The training program at ICRISAT gives peoplethe opportunity to work for between 6 monthsand 2 years in research programs of theInstitute. In the groundnut program, there arethree postdoctoral fellows who have come fromJapan, UK and USA; there are three researchscholars working for M.Sc. degrees, fromBenin, Ghana and India; finally, this year,there have been in-service trainees from thePeople's Republic of China, Sudan and Tanzania.This great diversity of workers has threemajor roles in the program: to gain experience;to familiarize staff members with newtechniques; and to carry out basic researchwhich may be outside the usual work ofICRISAT scientists. Since these last two rolesare particulary important for postdoctoral fellows,they will be emphasized in this paper.Research WorkGroundnut rust, Puccinia arachidis Speg. andthe two leaf spot fungi, Cercospora arachidicolaHori and Cercospondium personatum (Berk. &Curt.) Deighton, are extremely importantpathogens of groundnuts. In the USA, the leafspot fungi have been successfully controlled byfungicides (Backman et al. 1977); however thisapproach may not be feasible in less developedcountries. The use of disease resistant varietiesis an alternative method of control, but in thepast it was thought that there was no usefulvariation in leaf spot resistance within thecultivated species (Abdou et al. 1974;Hammons 1973). However, recent work hasdemonstrated that such variation does exist(Sowell et al. 1976; Hassan and Beute 1977;Melouk and Banks 1978; Nevill 1979; Subrahmanyamet al. 1980). In this paper, studies* International Intern, Groundnut ImprovementProgram, ICRISAT.into the nature and utilization of this resistancewill be described.Resistance to groundnut rust exists withi n thecultivated species (Mazzani and Hinojosa 1961;McVey 1965; Cook 1972), and at ICRISAT furtherstudies have been carried out to investigatescreening methods and the nature of the resistanceresponse. These will also be describedhere.The Potential of Disease ResistanceDuring the last two rainy seasons, the responseof 20 groundnut varieties to chemical diseasecontrol has been studied. Three fungicides havebeen used that control rust and leaf spot separatelyor together. Both diseases appear tocause similar yield losses (Table 1). Reductionin pod yield varied from 20 to 70% and if thislevel of resistance could be incorporated into ahigh yielding variety, such as Robut 33-1, thenyields of 4 t/ha could be achieved without theuse of fungicides.It must be stressed that these results provideonly an indication of the potential of diseaseresistance, si nee the effects of the chemicals ongroundnut development and on the supposedlyuncontrolled fungus are not known. This experimentis in progress, and from the results,Table 1. The response of four varieties tochemical disease control.Percentage yield losscaused by PotentialyieldVariety Rust Leaf spot Both (t/ha -1 )Robut 33- 1 27 38 70 4.8NC Acc 17090 14 17 30 3.4EC 76446 (292) 15 13 23 2.2PI 259747 10 18 37 2.0199

multiple point models of disease developmentwill be derived which should improve crop lossassessment methods.Laboratory Studiesof Leaf Spot ResistanceIn the laboratory, a simple detached leaftechnique is being used to study disease reactionsin detail. Groundnut leaves have abscissionlayers at the base of the leaflets and thepetiole. Excision through the pulvinus stimulatesrooting without the application of hormonesor specific nutrients if humid, moistconditions are maintained. Healthy leaves havesurvived for more than 3 months when culturedin moist sterile sand.To use this technique in screening testsleaves were placed in plastic seed trays with thecut pulvinus buried in a layer of wet sand. Theadaxial surfaces of the leaves were inoculatedwith an aqueous spore suspension and whenthe leaves were dry, the trays were placed intransparent plastic bags for incubation. Thismethod has been found to provide a screeningtechnique for which little equipment orresources are required, but which reducesenviornmental variability and avoids theconfounding effects of multiple infection.Use of this techniqu e has demonstrated largevarietal differences in the expression of C.personatum symptoms, particularly in haloformation. Components of resistance to thisfungus, when estimated in the laboratory weresignificantly correlated with field scores of resistancebased on a 0-9 scale. The characters— lesion diameter, incubation period, lesionnumber and defoliation — explained 54% ofthe variation in the field score when they wereincluded in a multiple regression analysis.This model has been able to rank 90% ofvarieties in a similar order to the field method. Abetter fit of the model would be achieved ifmore characters, such as latent period andsporulation, were included, but these are moredifficult to measure on a large number ofvarieties. Other reasons for the unexplainedvariation are inadequacies in the assumptionsof the regression model and imprecision in theestimates of the field scores.For a small number of varieties, a completestudy of components of the C. personatum andC. arachidicola disease reactions has been conducted.Resistance was associated with reducedsporulation, longer latent periods andless defoliation, but the success of spores inproducing lesions did not differ between varieties.Sporulation from resistant varieties wasone-quarter to one-sixth that from susceptiblevarieties (Fig. 1) and latent periods were increasedby 80%. These components havebeen integrated by means of a computer simulationmodel (Fig. 2). Using this technique,values of defoliation, leaf damage and sporeproduction are estimated for each day of asimulated growing season. The model predictsthat defoliation caused by the leaf spot pathogenscan be eliminated by use of the resistancelevels that exist within A. hypogaea. The computerprogram is being refined to improve therealism of the model.Figure 1.LABORATORYFigure 2.Days from inoculationDaily spore productionarachidicola lesions.SYSTEM CONSTRAINTSOnsetEnvironmentfrom C.PREDICTEDFIELD DATADiagrammatic representation of thesimulation model.200

Laboratory Studies of Rust ResistanceThe detached leaf technique has also been usedto study rust resistance. In this case it was foundthat most of the resistance components whichwere estimated in the laboratory were notcorrelated with a field score (0-9 scale). Onlyone character, i.e., numbers of lesions, gave asignificant regression and only 19% of thevariation in the field score was explained. It wastherefore concluded that only the most resistantand susceptible varieties could be separatedreliably by this technique. It is likely that thephysiology of interaction between P. arachidisand its host is extensively altered after excisionof the leaves.Some basic histological studies are beingcarried out to investigate the nature of rustresistance in the cultivated species. Events duringpenetration and early mycelial developmentare being studied using leaf clearing and stainingmethods. The mortality of developing rustinfections has been estimated using an approachsimilar to the life-table analysis ofhuman populations and some results areshown in Fig. 3.The percentage survival of two populations ofuredospores on leaves of a resistant and asusceptible variety declined during infection.Despite the occurrence of the highest mortalityduring penetration, resistance was expressedlater, during colony development. Similarly, instudies of immune wild species, P. arachidiswas able to penetrate through stomata, but inthis case development ceased after the formationof a single hypha out of the substomatalvesicle.There appear to be differences betweenspecies in the different sections of the genus intheir ability to penetrate (Table 2). These effectsare still being studied, since it may be possibleto introduce new types of resistance into thecultivated species, particularly from sectionRhizomatosae of the genus.The Genetic Controlof Leaf Spot ResistanceThe genetic control of leaf spot resistance isbeing studied in both field and laboratory experiments.Parents were selected using detachedleaf tests in April 1979 and F2 progenies werescreened as detached leaves during the postrainyseason of 1979-80. Thus, by using thistechnique, three generations have been grownand one generation has been tested within oneyear. If field tests of the selected F3 progeniesare successful, the technique should be a usefultool in rapid cycle backcross and recurrentselection breeding methods.In the F2 progenies, a great range of diseasereactions was observed and all components ofresistance were inherited in a quantitativemanner. Defoliation was controlled by geneswith additive action, but for other components,dominance effects were important and resistancewas recessive (Fig. 4). From the numbersFigure 3.Days after germinationMortality of P. arachidis during theinfection process (AP, Appressoriumformation; SSV, substomatalvesicle formation; EH, theproduction of an elongating hypha).Table 2. Percentage survival of groundnutrust during the Infection of threeArachis species.State of the infection process*Species GT AP SSV EH CFA. hypogaea(cv TMV-2)A. chacoenseA. glabrata10010010057503935351030 3030 08 0a. GT, germ tube formation (assumed value); AP, appressoriumformation over a stoma; SSV, the production of asub-stomatal vesicle; EH, the production of an elongatinghypha; CF, colony formation.201

ReferencesABDOU, Y. A. M., GREGORY, W. C, and COOPER, W. E.1974. Sources and nature of resistance to Cercosporaarachidicola Hori and Cercosporidium personatum(B&C) Deighton in Arachis species. PeanutScience 1: 6-11.BACKMAN, P. A., RODRIGUEZ-KABANA, P.., HAMMOND,J. M., CLARK, E. M., LYLE, J. A., IVEY, H. W., andSTARLING, J. G. 1977. Peanut leaf spot research inAlabama 1970-76. Bulletin 489, Agricultural ExperimentStation, Auburn, Alabama, U.S.A.Figure 4.Lesion diameter (mm)The frequency distribution of an F2population derived from crossingRobut 33-1 and Krapovickas Strain16.COOK, M. 1972. Screening of peanut for resistance topeanut rust in the greenhouse and field. PlantDisease Reporter 56: 382-386.HAMMONS, R. O. 1973. Genetics of Arachis hypogaea.Chapter 4 in Peanuts culture and uses. AmericanPeanut Research and Education Society.of resistant segregates, it is likely that genes at 3or 4 loci are controlling the disease reaction.The results of these tests are being confirmed infield trials this season.Furthergenetical studies which involve dialleland line x tester crossing systems, are beingconducted in the field. The results of this season'strials should provide a good deal ofknowledge about the genetics of leaf spot andrust resistance and also the relationship of thisresistance to plant yield.ConclusionDuring this project, a number of new techniqueshave been developed and demonstrated. Inparticular, tests of detached leaves have beenused to study disease reactions of F2 progeniesand computer modelling has been employed toinvestigate the relationship between field andlaboratory results. Fundamental studies of thenature of resistance have been initiated andhave provided a necessary basis for the moreapplied aspects of ICRISAT research. Thisbriefly demonstrates the ways in which a postdoctoralfellowship can contribute to thegroundnut research program.HASSAN, H. N., and BEUTE, M. K. 1977. Evaluation ofresistance to Cercospora leaf spot in peanut potentiallyuseful in a breeding program. Peanut Science4: 78-83.MCVEY, D. V. 1965. Inoculation and development ofrust on peanuts grown in the glasshouse. PlantDisease Reporter 49: 191-193.MAZZANI, B., and HINOJOSA, S. 1961. Differencias varietalesde susceptibilidad a la roya del mani enVenezuela. Agronomie Tropicale 11: 41-45.MELOUK, H. A., and BANKS, D. J. 1978. A method ofscreening peanut genotypes for resistance to Cercosporaleafspot. Peanut Science 5: 112-114.NEVILL, D. J. 1979. An investigation of disease reactionto Cercosporidium personatum in Arachishypogaea. Tropical Grain Legume Bulletin 15:18-22.SUBRAHMANYAM, P., McDONALD, D., GIBBONS, R. W.,NIGAM, S. N., and NEVILL, D. J. 1980. Resistance toboth rust and late leaf spot in some cultivars ofArachis hypogaea. Proceedings of the AmericanPeanut Research and Education Society 12 (inpress).202

International Aspectsof Groundnut Virus ResearchD. V. R. Reddy*Several virus diseases of groundnut occur in theSemi-Arid Tropics (RAT) (Chohan 1974; Feakin1973; lizuka et al. 1979; McDonald and Raheja1980) and some are economically important(Gibbons 1977; lizuka et al. 1979). Peanut mottlevirus (PMV) is the most widespread (Reddy et al.1978) and can cause considerable yield losses(Kuhn and Demski 1975). Other economicallyimportant virus diseases have more restricteddistributions. For instance, groundnut rosette isimportant in Africa, south of the Sahara (Gibbons1977; Gillier 1978; Rossel 1977; Yayock etal. 1976); peanut clump (PCV) in West Africa(Trochain 1931; Bouhot 1967; Germani et al.1975) and in India (Reddy et al. 1979); budnecrosis (caused by tomato spotted wilt virus-TSWV) in India (Ghanekar et al. 1979); andwitches' broom (a disease associated withmycoplasma-like organisms) in Southeast Asia(lizuka, personal communication).Applied research on plant virus diseases differsfrom that on fungal and bacterial diseasesbecause of the special nature of viruses. Someimportant prerequisites to the eventual controlof virus diseases are characterization of thecausal virus and elucidation of its mode oftransmission. Precise virus characterization involvescomplicated techniques which are constantlybeing improved as a result of rapidtechnological advances and increasing interestin the mode of replication of plant viruses.For effective management of plant virus diseasesit is essential that their ecology is understood.The distribution of each disease shouldbe ascertained and yield losses assessed. Highpriority should be given to screening for hostplant resistance and production of resistantcultivars and this depends on close cooperationwith scientists in other disciplines. To enablethese aims to be achieved it is necessary that* Principal Virologist, Groundnut ImprovementProgram, ICRISATsimple and effective techniques should be developedfor the detection and identification ofviruses.Problems of Virus Researchin the Semi-Arid Tropics (SAT)Most reports on the occurrence of groundnutvirus diseases in the SAT have been basedlargely upon visual symptoms. However, it iswell known that external symptoms can begreatly influenced by such factors as genotype,plant age, environment, and strain of viruspresent. On the basis of symptoms alone itappears that bud necrosis in India (Ghanekar etal. 1979) has been described under six differentnames; each being regarded as a new diseaseby the authors. Again, on the basis of externalsymptoms, rosette has been reported fromIndia, the Philippines, Indonesia, Australia,Russia and Argentina (Rossel 1977).For most areas of the SAT, data on theincidence and distribution of groundnut virusdiseases are either incomplete or lacking.Causal viruses, with very few exceptions (Bock1973; Germani et al. 1975; Dubern and Dollet1978 and 1979) have not been fully characterized.This is true even for groundnut rosettevirus which has been under investigation inAfrica for almost half a century. Reports onlimited characterization of this virus (Okusanyaand Watson 1966; Hull and Adams 1968) are yetto be confirmed.Losses due to diseases have been reliablyassessed for only few groundnut virus diseases,including those which have been characterized.Methods for screening groundnutgermplasm for resistance to viruses (and totheir vectors) have been developed for only afew diseases, and only in the case of groundnutrosette has there been successful developmentof resistant cultivars (Gibbons 1977; Gillier1978; Harkness 1977).203

The most important objectives of the ICRISATprogram are to characterize the economicallyimportant virus diseases in the SAT and topresent reliable data on their distribution andinterrelationships with similar viruses occurringin other countries.In order to provide a basis for the control ofvirus diseases, research should be pursuedinto: (1) screening for disease resistance inArachis hypogaea and in wild Arachis sp; (2) theeffect of cultural practices (including date ofsowing, spacing and intercropping) on the incidenceand spread of disease; and (3) avoidingsources of infection.Diagnosis of Groundnut VirusDiseasesVarious steps involved in the diagnosis of plantvirus diseases (Bos 1976) are given in Table 1.Table 1. Steps in the diagnosis of plant virusdiseases*1.2.3.4.5.6.7.8.9.10.11.12.13.Assessment of economic importance (incidence,distribution, and yield losses).Transmission by grafting, sap inoculation, insects,nematodes, etc.Inoculation to a series of test plants (preferably bymechanical sap inoculation) and back inoculationto a parallel range of test plantsto check possiblemultiple infection and host range.Identification of a host which consistently producescharacteristic symptoms, especially locallesions (diagnostic host).Identification of a systemically infected hostwhich supports high virus concentration (forpurification of viruses).Determination of biological properties using locallesion, assay (TIP, LIV and DEP).Examination under electron microscope (leaf dip,thin sections).Testing by serological methods.Development of methods to purify the virus.Determination of physico-chemical propertiesand electron microscopy of purified virus.Production of antiserum.Testing of serological relationships with similarviruses occurring elsewhere.Fulfillment of Koch's postulates, especially usingpurified virus... Modified from Bos (1976).Although it will eventually be necessary todiagnose virus diseases of minor importance,characterization of economically importantgroundnut virus diseases (bud necrosis, clumpand peanut mottle) has to receive top priority.Sap InoculationIn initial stages, sap transmission of virusespresent in crude groundnut leaf extracts couldbe achieved by adding reducing agents such as2-mercaptoethanol to extracting buffers. In addition,maintenance of low temperaturethroughout the inoculation process, determinationof optimum ionic strength and pH of phosphatebuffer, and the selection of only younginfected leaflets showing certain characteristicsymptoms, have facilitated mechanical sap inoculationof all groundnut viruses isolated sofar in India.Diagnostic HostsA large number of hosts commonly used in thediagnosis of virus diseases have been securedand are being maintained. From these, diagnostichosts have been selected for each of thevirus diseases characterized at ICRISAT.SerologyIf virus antisera are available, serologicaltechniques (Ball 1974; van Regenmortel 1978)offer effective means of diagnosis. They arerapid and can easily be standardized for thedetection of specific viruses. Conventionalserological techniques such as tube precipitin,micro-precipitin and precipitin ring tests havebeen used but have serious limitations for workwith groundnut viruses. For instance, they werenot successful when used for detection ofTSWV in groundnuts because of limitationssuch as low virus concentration in plant extractsand lack of high titred antisera.Three other serological techniques that havebeen used at ICRISAT with considerable successare Ouchterlony's agar gel doublediffusion(AGD); passive haemagglutination(PHA); and enzyme-linked immunosorbentassay (ELISA).In the AGD test, antigen and antibody areallowed to diffuse into agar. A positive reactionresults in the appearance of a thin white band204

where antigen and antibody meet. The test iseasy to perform and requires no specializedequipment (Ball 1974). It can be used to testseveral samples at the same time. By using theslight modification of incorporating 3,5-diiodosalycilic acid into the agar for dissociatinglong rod-shaped viruses, the test has beensuccessfully employed to detect PMV andCowpea mild mottle virus (CMMV) (Table 2).The PHA test (Ball 1974), one of the mostsensitive serological techniques, has been simplifiedand modified to prevent non-specificagglutination (Rajeswari et al„ in press).Glutaraldehyde-fixed red blood cells, aftertreatment with tannic acid, are coated withantiserum. Antibody sensitized red blood cellsare then added to various dilutions of testsolutions. The test is performed in lucite platescontaining 'U'-shaped wells and in a positivereaction red cells agglutinate, forming a smoothmat with a serrated margin on the bottom of thewell. In a negative reaction, red cells form adiscrete red ring at the periphery of the well.The PHA test is extremely sensitive, easy tooperate, does not need specialized equipmentor reagents, and requires much less antiserathan the AGD test. The PHA technique can beused to detect viruses in crude plant extracts.The test has been successful in the detection ofTSWV antigens in infected groundnut plantsand in the thrips vector. The test has also beensuccessfully used for the detection of othereconomically important virus diseases in India(Table 2).Both AGD and PHA techniques were tried fordetection of viruses in seeds but without success.The ELISA technique was acquired andsuccessfully adopted for detection of PMV inseed (Reddy et al., in preparation). The ELISAtest is by far the most sensitive and specificTable 2.Characterization of important viral dlseases of groundnut in India.Name of the viruscharacterization TSWV PCV PMV CMMV1. SerologyGel diffusionHaemagglutinationELISA?+++#+++++*2. Electron microscopyPlant materialPurified virus+**+++#+3. TransmissionMechanicalVectorSeed++++?+++ ?+4. Physicochemical propertiesSedimentation coefficientM.W. of proteinM.W. of nucleic acid#«##+*+++*++5. Host range + + + +6. Biological propertiesTIPLIV++++++++7. SymptomsGroundnutDiagnostic host+++++++++ = Positive result, - - Negative result. *= Not performed, ? > > Data Inconclusive205

serological technique now available for detectionof plant viruses (Clark and Adams 1977;Voller et al. 1976). The procedure is simple andrapid. The y-globulins extracted from antisera,are absorbed to welts of a special microtiterplate. Test samples, including crude plant extracts,purified viruses and extracts from seed,are added to the wells. If the test samplecontains specific viral antigens, theseare boundtothe y-globulins coated on the inner surface ofthe well. Thetest samples are washed away andenzyme-conjugated y-globulins are added tothe wells. The labelled antibodies bind to theviral antigen already bound to the y-globulinscoated on the plastic surface. Finally, a substratefor the enzyme, which was used earlierfor conjugating '/-globulins is added to the well.The color change in the substrate is proportionalto the amount of enzyme present, whichin turn is proportional to the viral antigenconcentration.The two major limitations of ELISA are theneed for high titered antisera and specializedreagents and plates for performing the test.Using the ELISA technique, it has been possibleto screen nearly 1000 kernels for presence ofPMV in two days. It would take nearly onemonth to field plant seed and score visually forPMV symptoms. A small portion of the cotyledonis adequate for detecting the virus. Inaddition, PMV could be detected in crude plantextracts d iluted to 1:10000.Experiments are under way to employ ELISAfor the detection of other groundnut virusesand especially for monitoring field collectedviruliferous vector populations.Electron MicroscopyElectron microscopy is an essential techniquefor the detection and identification of plantviruses. An electron microscope has recentlybeen installed at ICRISAT and facilities areavailable for fixation, embedding and thin sectioningof plant material. Purified preparationsof PCV, PMV and CMMV have been examined.Tomato spotted wilt virus and PMV could belocalized in thin sections of infected plant material.PurificationPurification of plant viruses is essential toproduce antisera, for determining physicochemicalproperties and for electron microscopy.Purification of viruses requires expensivelaboratory equipment such as a refrigeratedsuperspeed centrifuge, an ultracentrifuge, aspectrophotometer and a gradient scanner. Inaddition, expertise is required for virus purification.However, with the aid of a refrigeratedsuperspeed centrifuge it would be possible topartially purify viruses and prepare electronmicroscope grids for examination at ICRISAT.Several physicochemical techniques arenow available for separating virus particlesfrom the normal constituents of their host cell,and the art of purification is to exploit thesetechniques so as to produce highly infectivevirus preparations as free as possible from hostmaterial. Groundnut tissue contains an excessof tannins which normally interfere in viruspurification. At least one more suitable host hasbeen discovered for each one of the groundnutviruses characterized at ICRISAT for use in viruspurification. Various buffers, with specific ionicstrength and pH values, have been used successfullyto stabilize viruses in the initial purificationsteps which involve extraction from theleaves, clarification with organic solvent, precipitationwith polyethylene glycol (PEG) andsubsequent resuspension of PEG precipitates.Further purification has been achieved in rateand quasi-equiiibrium zonal density gradientcentrifugation in sucrose solutions.Purification techniques specific for PMV, PCVand CMMV have been developed to obtain highvirus yields and high specific infectivity with nodetectable impurities (Table 3). Tomato spottedwilt virus is known to be one of the most difficultviruses to purify, but a purification methoddeveloped at ICRISAT should soon be available.Physicochemical PropertiesSpecialized skills and experience, and specialequipment, are required to characterize virusesby physico-chemical methods. Thesetechniques usually complement the results ofelectron microscopy and serology but are indispensablein determining relationshipsamong similar viruses and in distinguishingstrains. Molecular weight determination of viralproteins and nucleic acids employing polyacrylamidegel electrophoresis (Adesnik 1971;Maizel 1971; Reddy and Black 1973; Reddy and206

Table 3. Virus purification methods davalopad at ICRISAT Center.To obtain: High virus yields For: Peanut mottle virusNo detectable impuritiesCowpea mild mottle virusHigh specific infectivityPeanut green mosaic virusPeanut clump virusTomato spotted wilt virusMacLeod 1976) has now become an indispensabletool for rapid characterization of viruses.Chemical characterization has been successfullyemployed at ICRISAT to distinguish themorphologically identical PMV and peanutgreen mosaic virus (both belong to the potatovirus Y group) and the morphologically similarCMMV which belongs to the Carla Virus group)(Table 2).GeneralThe important criteria employed in the characterizationof groundnut viruses are given inTable 4. A series of occasional papers, describingdetails of all the steps involved in each ofthe techniques employed for the diagnosis ofgroundnut viruses at ICRISAT, is under preparation.Table 4.Diagnosis of virus diseases.Identification depends onSerologyElectron microscopyTransmissionPhysicochemical propertiesHost rangeSymptomatologyManagement of Virus DiseasesWith the exception of PCV and CMMV thevectors of all groundnut viruses, characterizedat ICRISAT, have been identified (Table 5).Studies on various factors contributing to themultiplication and spread of vectors have providedus with ways and means of managing thediseases. For instance, cultural practices (dateof sowing, and plant spacing) have been successfullyemployed to reduce losses from budnecrosis (TSWV). In addition, identification ofTable 5.Vectors of virus diseases identifiedat ICRISAT Center.1. Bud necrosis : Scirtothrips dorsalis(Tomato spotted Frankliniella schultzeiwilt virus)2. Peanut mottle : Aphis craccivoraMyzus persicae3. Peanut clump : Nematodes (?)4. Yellow spot (Tomato : Scirtothrips dorsalisspotted wilt virus?)5. Peanut green mosaic : Aphis gossypiiMyzus persicaevectors and virus-vector relationship have beenhelpful, in the diagnosis of TSWV and PMV.Large scale methods for screening germplasmhave been developed and sources of resistancehave been identified for some viruses.Groundnut Virus Researchin the SATThe techniques described for detection, identificationand purification of viruses requireelaborate and expensive equipment (Table 6)and availability of highly trained scientific andtechnical staff. The virus laboratory at ICRISATand a relatively small number of otherlaboratories in the SAT are so equipped. Itwould not be practical to set up suchlaboratories in all areas of the SAT whereresearch on groundnut viruses is considereddesirable. However, the absence of a fullyequipped and staffed virus laboratory does notmeanthat useful research ongroundnutvirusescannot be undertaken.Groundnut virologists from ICRISAT, or fromother institutions where specialized virus researchis being undertaken, could visit differentareas of the SAT and in collaboration with207

Table 6. Requirements for virology research.1. Maintenance and transmission*Glass or screenhouse*AutoclaveII. Serology*Clinical centrifuge*Hot water bathSpecial chemicals, platesIII. Production of antisera*Animal house*RabbitsIV. Diagnosis*Diagnostic hostsChemical characterizationElectrophoresis apparatus•SpectrophotometerV. Purification•Ref. superspeed centrifugeUltracentrifugeGradient scannerVI. Electron microscopyFixing and embeddingElectron microscopeVacuum coating deviceUltra microtome* Essentialnational scientists carry out surveys to determinethe occurrence and distribution of importantgroundnut virus diseases. The basictechnology for such work could readily beprepared at ICRISAT and taken to the surveyareas. This would include a supply of seed ofdiagnostic hosts, antisera for use with PHA andELISA techniques and fixatives to prepare tissuesfor eventual electron microscopy.Antisera can be stored for long periods at lowtemperature without considerable loss of theirtiters. Gluteraldehyde-fixed red blood cells canbe held at room temperatures for at least aweek, without impairing their suitability forsensitization; and if kept at low temperaturesthey are suitable for use in the PHA test after 3months of storage.If it were desired to test seeds or plant tissuesfor the presence of PMV, the ELISA techniquecould be employed. At ICRISAT, y-globulinsand enzyme labelled y-globulins could be preparedand taken to the laboratory where testswere to be done. These preparations can bekept at room temperature for 10 days withoutdamage and stored at low temperature for overa year.Where no electron microscope facility isavailable locally, it would be possible to fix andembed plant tissues for later sectioning andexamination at ICRISAT. Where no facilities forfixation and embedding exist, it would besufficient to infiltrate portions of plant tissueswith gluteraldehyde; this process being carriedout at reduced atmosphere pressure. Suchmaterials could be shipped to ICRISAT, oranother laboratory with electron microscopyfacilities.Problems could arise where an importantvirus disease was of relatively restricted distributionand where no fully equipped viruslaboratory was available to carry out viruspurification and production of antisera.Irrespective of the presence of a similar diseasein India, it would not be possible for suchwork to be carried out at the ICRISAT Centerbecause of plant quarantine laws prohibitingthe importation of live viruses. This problemcould be solved if virus laboratories in technicallyadvanced countries where groundnuts arenot grown could cooperate in purification andantisera production. A number of suchlaboratories have already shown interest insuch cooperation.Cooperation is also envisaged between viruslaboratories in the exchange of antisera, seed ofdiagnostic hosts, and other materials useful invirus identification. Every effort should be madeto expedite publication of research findings andin particular to make available data on newtechniques.An important part of the work of ICRISAT isthe collection, recording and dissemination ofresearch data and the provision of specializedtraining and opportunities for cooperative research.As already mentioned, papers are beingprepared on the various techniques used in thegroundnut virus research laboratory. Trainingcan be given on these techniques and on otherrelevant techniques in the associated fields ofentomology (identification and control of virusvectors), plant breeding (screening ofgermplasm and production of resistant cultivars)and cytogenetics (utilization of wildArachis species as sou rces of resistance to virusdiseases). It can also be arranged for virologiststo make visits of varying duration to ICRISAT todiscuss collaborative projects, acquire exper-208

tise in specific techniques, or to process theirown research materials.ReferencesADESNIK, M. 1971. Polyacrylamide gel electrophoresisof viral RNA. Pages 126-175/W Methods in virology(K. Maramorosch and H. Koprowski eds.) Vol. 5.Academic Press, New York.BALL, E. M. 1974. Serological tests for the identificationof plant viruses. American PhytopathologicalSociety. St. Paul, USA. 1-30 pp.BOCK, K. R. 1973. Peanut mottle virus in East Africa.Annals of Applied Biology 74: 171-179.Bos, L. 1976. Research on plant virus diseases in developingcountries: Possible ways for improvement.FAO Plant Protection Bulletin 24: 109-118.BOUHOT, D. 1967. Observations sur quelques affectionsdes plantes cultivees au Senegal. AgronomieTropicale Nogent 22: 888-890.CHOHAN, J. S. 1974. Recent advances in diseases ofgroundnut in India. Pages 171-184 in CurrentTrends in Plant Pathology, (eds. S. P. Raychaudhuriand J. P. Verma). Lucknow University, India.CLARK, M. F., and ADAMS, A. N. 1977. Characteristics ofthe microplate method of enzyme linked immunosorbentassay for the detection of plant viruses.Journal of General Virology 34: 475-483.DUBERN, J., and DOLLET, M. 1978. Observation d'unenouvelle maladie a virus en Cote - d'lvoire: lamaladie des taches ocetlees de I'arachide.Oleagineux 33: 175-177.DUBERN, J., and DOLLET, M. 1979. Groundnut crinkle, anew virus disease observed in Ivory Coast.Phytopathologische Zeitschrift 95: 279-283.FEAKIN, S. D. 1973. Pest control in groundnuts. Pages81-89 in PANS Manual No. 2. Centre for OverseasPest Research, London, UK.GERMANI, G.,THOUVENEL, J. C, and DHERY, M. 1975. Lerabougrissement de I'arachide. Une maladie a virusau Senegal et en Haute-Volta. Oleagineux30: 259-266.GHANEKAR, A. M., REODY, D. V. R., IIZUKA, N., AMIN,P. W., and GIBBONS, R. W. 1979. Bud necrosis ofgroundnut (Arachis hypogaea) in India caused bytomato spotted wilt virus. Annals of Applied Biology93: 173-179.GIBBONS, R. W. 1977. Groundnut rosette virus. Pages19-21 in Diseases, pests, and weeds in tropicalcrops. Edited by J. Kranz, H. Schumtterer, and W.Koch. Verlag Paul Parey, Berlin.GILLIER, P. 1978. Nouvelles limites des culturesd'arachides resistantes a la secheresse et a larosette. Oleagineux 33: 25-28.HARKNESS, C. 1977. The breeding and selection ofgroundnut varieties for resistance to rosette virusdisease in Nigeria. Report submitted to the AfricanGroundnut Council.HULL, R., and ADAMS, A. N. 1968. Groundnut rosettevirus and its assistor virus. Annals of Applied Biology62: 139-145.IIZUKA, N., REDDY, D. V. R., and GHANEKAR, A. M. 1979.Identification of some viral diseases of groundnut inIndia. Paper presented at the Legumes in Tropicssymposium, Malaysia.KUHN, C. W., and DEMSKI, J. W. 1975. The relationshipof peanut mottle virus to peanut production. ResearchReport. Agricultural Experiment Station,University of Georgia, USA.M AIZEL, J. V. 1971. Polyacrylamide gel electrophoresisof viral proteins. Pages 179-246 in Methods in Virology(K. Maramorosch and H. Koprowski eds). Vol.5. Academic Press. New York.MCDONALD, D., and RAHEJA, A. K. 1980. Pests, diseases,resistance and crop protection ingroundnuts. In Advances in legume science (eds.Summerfield and Bunting). Vol. 1. Proceedings ofthe International Legume Conference, Kew, England.OKUSANYA, B. A. M., and WATSON, M. A. 1966. Hostrange and some properties of groundnut rosettevirus. Annals of Applied Biology 58: 377-387.RAJESHWARI, R., REDDY, D. V. R., and IIZUKA, N. 1981.Improvements in the passive haemagglutinationtechnique for serological detection of plant viruses.Phytopathology (In press).REDDY, D. V. R., and BLACK, L. M. 1973. Electrophoreticseparation of all components of the doublestrandedRNA of wound tumor virus. Virology54: 557-562.REDDY, D. V. R., and MACLEOD, R. 1976. Polypeptidecomponents of wound tumor virus. Virology70: 274-282.REDDY, D. V. R., IIZUKA, N„ GHANEKAR, A. M., MURTHY,V. K., KUHN, C. W., GIBBONS, R. W., and CHOHAN, J. S.209

1978. The occurrence of peanut mottle virus In India.Plant Disease Reporter 62: 978-982.REDDY, D. V. R., llZUKA, N., SUBRAHMANYAM, P.,RAJESHWARI, R., and MCDONALD, D. 1979. A soilbornedisease of peanut in India. Proceedings ofAmerican Peanut Research and Education Society11: 49.REDDY, D. V. R., LISTER, R. M., and RAJESHWARI, R.Detection of peanut mottle virus in peanuts employingenzyme linked immunosorbent assay (In preparation).ROSSEL, H. W. 1977. Some observations and experimentson groundnut rosette virus and its control inNigeria. Miscellaneous paper 71. Institute of AgriculturalResearch, Samaru, Nigeria.TROCHAIN, J. 1931. La "Lepre de I'Arachlde. Revue DeBotanique Appliquee Et Agriculture Tropicale11: 330-334.VANREGENMORTEL, M. H. V. 1978. Application of plantvirus serology. Annual Review of Phytopathology16: 57-81.VOLLER, A. M., BIDWELL, D. E., and BARTLETT, A. 1976.Enzyme immunoassays in diagnostic medicine. Bulletinof World Health Organization 53: 55-65.YAYOCK, J. Y., ROSSELL, H. W., and HARKNESS, C. 1976.A review of the 1975 groundnut rosette epidemic inNigeria. Paper presented at the African GroundnutCouncil Symposium.210

Groundnut Virus Research at ICRISATA. M. Ghanekar*Several virus diseases of groundnut have beenreported in India based on symptoms, hostrange and biological properties. These propertiesare now regarded as inadequate to identifya virus. Characterization should be based onserology, electron microscopy, transmissionand physico-chemical properties.Three economically important virus diseases(bud necrosis, clump and peanut mottle) andseveral virus diseases of minor importance inIndia have now been fully characterized.Bud Necrosis DiseaseBud necrosis disease caused by tomato spottedwilt virus (TSWV) has been recognized as oneof the most important virus diseases ofgroundnuts in India (Chohan 1974; Ghanekar etal. 1979). The disease has also been reported ongroundnuts in several other countries includingBrazil, USA, S. Africa and Australia (Costa 1941;Halliwell and Philley 1974; Klesser 1966; Helmset al. 1961). A clear account of the diseasesymptoms was given by Reddy et al. (1968).The causal virus was characterized at ICRISAT(Ghanekar et al. 1979) and the thrips vectorchiefly responsible for transmitting the diseasewas identified (Amin et al. 1978). Bud necrosishas been shown to cause yield losses of up to50% and occurs in all the major groundnutgrowing areas of India. The incidence rangesfrom 5 to 80% in different parts of the country(Chohan 1972; Ghanekar et al. 1979).S y m p t o m s o n G r o u n d n u tThe typical disease symptoms on groundnutinclude chlorotic rings, terminal bud necrosis,severe stunting, proliferation of axillary shoots* Plant Pathologist, Groundnut Improvement Program,ICRISAT.with deformed leaves and production of discoloredand shrivelled kernels.Diagnostic HostsThe virus produces chlorotic and necrotic locallesions on Vigna unguiculata (cowpea cv C-152)and necrotic local lesions onPetuniahybrida (cvCoral Satin) which do not become systemic.Host RangeThe virus was found to have extremely widenatural and experimental host ranges. Vignaradiata (cv Hy-45), Vigna mungo (cv UPU-1),Phaseolus vulgaris (cv Local), Vicia faba,Lycopersicon esculentum (cv Pusa Ruby) andPisum sativum were all susceptible to infectionby TSWV. In addition a number of weedscommonly encountered in groundnut fieldswere also susceptible.Biological PropertiesThe virus has a thermal inactivation point at46°C and the longevity in vitro is approximately5 hours at 25°C. These properties indicated thatbud necrosis could be related to tomato spottedwilt virus.Electron MicroscopyThin sections of groundnut leaves under theelectron microscope showed membrane boundvirus particles 70-90 nm in diameter and wereassociated with the endoplasmic reticulum.These particles resemble those of TSWV.SerologyAntisera for TSWV obtained from the USA andS. Africa when used in haemagglutination testsclearly revealed the presence of viral antigens incrude bud necrosis infected groundnut extracts.211

TransmissionThe virus was mechanically sap transmissiblefrom plant extracts prepared in 0.05M potassiumphosphate buffer (pH 7.0) containing0.02M 2-mercaptoethanol added as an antioxidant.It was consistently transmitted byFrankliniella schultzei (Trybom) and to a lesserextent by Scirtothrips dorsalis Hood. Thevirus was not transmissible through seed ofgroundnut (Ghanekar et al. 1979).C o n t r o lExperiments on effects of date of sowing, plantspacing and intercropping with pearl millet ondisease incidence are giving promising results.Early planting at the onset of the rainy seasondecreased disease incidence and reducedlosses from bud necrosis disease. Planting athigh density also reduced disease incidence(Table 1).Experiments on the effect of intercroppingwith pearl millet were started recently andpreliminary observations show a lower diseaseincidence in the intercropped situation whencompared with the sole crop.Screening for Disease ResistanceSo far nearly 7000 germplasm lines of Arachishypogaea have been screened under highnatural disease incidence in the field and noneshowed any marked resistance to the virus.However, the cultivars Robut 33-1 and NC Acc2575 consistently showed lower than averageincidence of the disease under field conditions.Several wild Arachis species have beenscreened under high natural disease incidencein the field, and also by mechanical sap inoculationin the screenhouse. So far Arachischacoense, A. glabrata, Arachis sp (PI 262848)and Arachis pusilla have not become infected inthesetests, butthese results need confirmation.Cultural PracticesAs sources of resistance are still being sought,efforts are being concentrated on the developmentof cultural practices to control the disease.Peanut (Groundnut)Clump VirusA disease of groundnuts resulting in severelystunted plants with small, dark green leaveswas observed in 1977 in crops grown in thesandy soils of Punjab and Gujarat. Most of theinfected plantsfailed to produce pods, and evenin cases of late infection, losses of up to60% were recorded. A sap transmissiblevirus which reproduced the disease symptomswas isolated and is being characterized.Symptoms on GroundnutInfected plants are severely stunted with smalldark green leaves. The young quadrifoliateleaves show mosaic mottling and chloroticrings. Roots become dark colored and theouter layers peel off easily.Table 1. Effect of plant spacing on the incidence of bud necrosis disease (TSWV).Postrainy seasonPostrainy seasonInterrow andIntrarow plantspacing1978--79Disease Yield1979--80Disease Yield(cm) (%) (kg/ha) (%) (kg/ha)37.5 x 5.0 10 3493 7 215337.5 x 15.0 23 2855 16 152475.0 x 5.0 20 2289 9 157075.0 x 15.0 40 1745 18 917150.0 x 5.0 23 1270 11 740150.0 x 15.0 43 777 21 409212

Diagnostic HostsPhaseolus vulgaris (cv Local), on which thevirus produces veinal necrosis, and Canavaliaensiformis, on which discrete necrotic lesionswith chlorotic centers are produced, have beenidentified as diagnostic hosts.Host RangeThe virus has an extremely wide host rangeand several weeds commonly occurring ingroundnut fields are also infected by the virus.Biological PropertiesThe thermal inactivation point of the virus isbetween 60° and 65°C and longevity in vitro is2-3 days at room temperature.means of mechanical inoculations and grafting.The following observations suggested thatthe virus was soilborne and possibly transmittedby nematodes: (1) the disease was restrictedto sandy soils; (2) infected plants couldbe obtained by sowing healthy seeds in soilsamples collected from depths of 12-28 cm ininfected fields; (3) the disease occurred inpatches in the field and reappeared in the samepositions in succeeding years; (4) air-driedsoil could not reproduce the disease; and(5) nematocide applications to infested soils reducedthe incidence and spread of the disease.Nematodes isolated from infested soils, andinoculated onto healthy plants grown insterilized soil produced the disease in somerecent tests. These results need to beconfirmed.PurificationNicotiana hybrid (N. clevelandii x N. glutinosa)consistently gives high virus concentrations. Amethod to purify the virus from crude Nicotianahybrid leaf extracts has been successfully devised.Polyethylene glycol precipitates ofchloroform treated infected leaf extracts aresubjected to density gradient centrifugation insucrose solutions. Virus obtained from thegradients can be inoculated onto healthygroundnut plants and diagnostic hosts where itproduces typical symptoms.Electron MicroscopyPurified virus preparations, and leaf dips ofinfected leaves of groundnut and Nicotianahybrid, revealed the presence of rod-shapedvirus particles of 200-500 nm in length, and23-25 nm in width, with a central hollow core.SerologyAntisera were obtained of strains of the soilbornetobacco rattle and pea early browingviruses which have particle morphology similarto the clump virus. These were tested againstcrude plant extracts and purified extracts ofclump virus but there was no positive reaction.TransmissionThe virus was successfully transmitted byRelationship w i t h Similar VirusesReported on GroundnutsBased only on symptoms, Sundararaman(1927) described a similar disease in India,which he named clump.The symptoms observed also resemble thoseof clump disease reported from West Africa(Germani et al. 1975). In both cases the diseasewas soilborne and application of Nemagonreduced the disease (Germani et al. 1973).Both diseases are caused by viruses withsimilar particle structure (Germani et al. 1975;Thouvenel et al. 1976). However, both viruseshave to be tested serologically before the relationshipbetween them can be confirmed.ControlNematocide and Fungicide TreatmentsIn collaboration with the Oilseeds Sectionof Punjab Agricultural University, the nematocidesNemagon, Carbofuran, Temik anda mixture of the fungicides Bavistin and Blitox,were tested for their effect in controlling thedisease. Untreated plots served as controls. Thechemicals were applied to the soil 1 weekbefore planting and the susceptible cultivarM-13 was used. Nemagon and Temik were themost effective in reducing the disease incidenceand increasing the yield when compared withuntreated plots.213

Screening f o r Disease ResistanceScreening was carried out in infected soilsof the Punjab where the disease had beenrecurring for three consecutive years. Theplots selected had shown up to 98% incidenceof the disease in the previous season. A susceptiblecultivar M-13 was sown after every 10test cultivars. Eight cultivars (M 884-75, C 334-AB-13, NC Acc 17847, NC Acc 17866, NC Acc17732, NC Acc 17740, NC Acc 17840, and EC21887) showed no disease symptoms.Another ten cultivars showed a very lowincidence of visibly diseased plants. These cultivarswill be retested under field and laboratoryconditions before any conclusions on theirpossible resistance or tolerance can be drawn.Peanut (Groundnut)Mottle VirusPeanut mottle virus (PMV) is widespread andhas been positively identified in the USA (Kuhn1965), E. Africa (Bock 1973), Australia(Behncken 1970), Europe (Schmidt et al. 1966),Japan (Inouye 1969), the Philippines (Benignoet al. 1977), South America (Herold et al. 1969),West Malaysia (Geh et al. 1973) and India(Reddy et al. 1978). The disease also appears tobe present in China (Gibbons, personal communication).The disease can cause up to 30%loss in yield (Kuhn et al. 1975).S y m p t o m s o n G r o u n d n u tNewly formed leaves show mild mottling andvein clearing, whereas older leaves show upwardcurling and interveinal depression withoccasional dark green islands. Infected plantsare not severely stunted and older plants seldomshow typical disease symptoms.Diagnostic HostThe virus produces reddish brown necroticlesions on inoculated leaves of Phaseolus vulgaris(cv Topcrop) which was found to be agood diagnostic host for the virus.Host RangeThe virus has a narrow host range and infectsmostly legumes.Biological PropertiesThe virus has a thermal inactivation point between55° and 60°C and longevity in vitro is 48hours at 25°C.Purification a n d A n t i s e r u mProductionThe virus has been successfully purifiedemploying a method developed at ICRISAT(lizuka et al. in preparation). An antiserum hasbeen produced by injecting purified virus preparationsinto rabbits.Electron MicroscopyPurified virus preparations and sections of infectedleaves, when observed under the electronmicroscope, reveal the presence of long,flexuous, rod-shaped particles of 700 nm inlength.SerologyAn antiserum obtained from the USA, and oneproduced at ICRISAT, were reacted with PMVusing agar gel diffusion, haemagglutinationand Enzyme Linked Immuno Sorbant Assay(ELISA) tests. Positive results were obtained inall tests for PMV.TransmissionThe virus is seed transmitted in a rangefrom 0.1 to 3.5% depending on the groundnutcultivars.Aphis craccivora and Myzus persicae transmitthe virus in a stylet-borne (non-persistent)manner.ControlScreening for Disease ResistanceThe natural incidence of PMV is not highenough for meaningful screening of cultivarsfor resistance in the field. It was thereforenecessary to reproduce the disease on a largescale underfield conditions. A spray inoculationtechnique has been developed in which inoculumis mixed with celite and sprayedthrough fine nozzles at 50 PSI. About 1000214

plants can be inoculated in one hour and about80% of the plants become infected.An earlier report indicated that no immunityhad been found to peanut mottle virus (Kuhn1968) in groundnut cultivars from differentparts of the world. However, tolerance of somecultivars to PMV where there is no reduction inyield even though plants became infected, wasreported (Kuhn et al. 1978). Using the inoculationtechnique described, about 200 cultivarshave been screened sofarand yield losses havebeen estimated. None of the cultivars testedshowed immunity or tolerance to PMV.Screening Cultivarswhich do not Transmitthe Virus Through the SeedDiseased plants with infected seeds are theprimary sources of inoculum. The secondaryspread is by aphids which acquire the virusfrom plants infected through seeds. It would bedesirable to have a cultivar which did nottransmit the virus through the seed. Approximately1000 seeds were obtained from infectedplants of a range of cultivars. So far two cultivars,EC 76446 (292) and PI 259747, have notshown any seed transmission. Over 5000 seedsfrom infected plants of these cultivars will soonbe tested under field conditions.Virus Diseasesof Minor ImportanceCowpea mild mottle virus (CMMV) and peanutgreen mosaic virus (PGMV) have been characterizedon the basis of electron microscopy,serology, chemical characteristics and hostrange. CMMV has been detected occurringnaturally in the Punjab, Andhra Pradesh andUttar Pradesh but the incidence is less than1%. PGMV has so far been detected only in theChittoor district of Andhra Pradesh.ReferencesAMIN, P. W., REDDY, D. V. R., and GHANEKAR, A. M. 1978.Transmission of bud necrosis virus (BNV) ofgroundnut by chilli thrips, Scirtothrips dorsalis(Thysanoptera, Thrlpidae). Indian Phytopathology31: 118 (Abstract).BEHNCKEN, G. M. 1970. The occurrence of peanutmottle virus in Queensland. Australian Journal ofAgricultural Research 21: 465-472.BENIGNO, D. A, and FAVALI-HEDAYAT, M. A. 1977.Investigation on previously unreported or noteworthyplant viruses and virus diseases in Philippines.Food and Agriculture Organization Plant ProtectionBulletin 25: 78-84.BOCK, K. R. 1973. Peanut mottle virus in East Africa.Annals of Applied Biology 74: 171-179.CHOHAN, J. S. 1972. Final Progress Report. ICARscheme for research on important diseases ofgroundnut in the Punjab for the period 1957-1967.Department of Plant Pathology, Punjab AgriculturalUniversity, Ludhiana, India, 117 pp.CHOHAN, J. S. 1974. Recent advances in diseases ofgroundnut in India. Pages 171-184 in CurrentTrends in Plant Pathology. (Eds. S. P. Raychauduriand J. P. Verma). Lucknow University, India.COSTA, A. S. 1941. Una molestia de virus do amendoim{Arachis hypogaea L). A mancha anular.Biologico 7: 249-251.GEH, S. L., and TING, W. P. 1973. Loss in yield ofgroundnuts affected by groundnut mosaic vimsdisease. Malaysian Agriculture Research DevelopmentInstitute Research Bulletin 1: 22-28.GERMANI, G., and DHERY, M. 1973. Observations et experimentationsconcernant le role des nematodesdans deux affections de I'Arachide en Haute Volta:la "chlorose" et le "clump". Oleagineux 28: 235-242.GERMANI, G„ THOUVENEL, J. C, and DHERY, M. 1975. LerabougrissementdeI'Arachide: Unemaladieavirusau Senegal et en Haute-Volta. Oleagineux30: 259-266.GHANEKAR, A. M., REDDY, D. V. R., IIZUKA, N., AMIN, P. W.,and GIBBONS, R. W. 1979. Bud necrosis of groundnut[Arachis hypogaea L.) in India caused by tomatospotted wilt virus. Annals of Applied Biology93: 173-179.HALLIWELL, R. S., and PHILLEY, G. 1974. Spotted wilt ofpeanut in Texas. Plant Disease Reporter 58: 23-25.HELMS, K., GRYLLS, N. E., and PURSS, G. S. 1961. Peanutplants in Queensland infected with tomato spottedwilt virus. Australian Journal of Agricultural Research12: 239-246.215

HEBOID, F., and MUNZ, K. 1969. Peanut mottle virus.Phytopathology 59: 663-666.IIZUKA, N., RAJESHWARI, R., and REDDY, 0. V. R. Purificationand chemical characterization of peanut mottlevirus (in preparation).INOUYE, T. 1969. Peanut mottle virus from peanut andpea. Nogaku Kenkyu 52: 159-164.K LESSER, P. J. 1966. Tomato spotted wilt virus onArachis hypogaea. South African Jou rnal of Ag ricu I-ture Science 9:731-736.KUHN, C. W. 1965. Symptomatology, host range andeffect on yield of a seed transmitted peanut virus.Phytopathology 55: 880-884.KUHN, C. W., and DEMSKI, J. W. 1975. The relationshipof peanut mottle virus to peanut production. ResearchReport. Agriculture Experiment Stations,University of Georgia, USA.KUHN, C. W., SOWELL, G. Jr., CHAKLEY, J. H., andSTUBBS, H. F. 1968. Screening for immunity topeanut mottle virus. Plant Disease Reporter56: 467-468.KUHN, C. W., PAGUIO, O. R., and ADAMS, D. B. 1978.Tolerance in peanuts to peanut mottle virus. PlantDisease Reporter 62: 365-368.NABIANI, T. K., and DHINGRA, K. L. 1963. A mosaicdisease of groundnut (Arachis hypogaea L). IndianJournal of Agricultural Science 33: 25-27.REDDY, M., REDDY, D. V. R., and APPA RAO, A. 1968. Anew record of virus disease on peanut. Plant DiseaseReporter 52: 494-495.REDDY, D. V. R., IIZUKA, N., GHANEKAB, A. M., MUBTHY,V. K., KUHN, C. W., GIBBONS, R. W., and CHOHAN, J. S.1978. The occurrence of peanut mottle virus in India.Plant Disease Reporter 62: 978-982.SCHMIDT, H. B., and SCHMELZEB, K. 1966. ElektronenmikroskopischeDarstellung and vermessung einessaftubertragbar virus aus der Erdnuss (Arachishypogaea L). Phytopathologische Zeltschrift55: 92-96.SUNDABA RAMAN, 1926. A clump disease ofgroundnuts. Madras Agricultural Department YearBook 1926: 13-14.THOUVENEL, J. C, DOLLET, M„ and FAUQUET, C. 1976.Some properties of peanut clump, a newly discoveredvirus. Annals of Applied Biology 84: 311-320.216

Session 7 — Groundnut PathologyDiscussionB. S. GillRust was first reported from the Punjab inIndia and now its incidence is increasing veryfast in many parts of the country, but atpresent there is no rust in the Punjab. Has Dr.Subrahmanyam any explanation for this?P. SubrahmanyamIt is difficult to explain, but rust was firstreported from the greenhouse in the Punjaband not the field. Moreover, in Punjabgroundnut is a rainfed crop taken once in ayear, whereas in other parts of Indiagroundnuts are grown throughout the year.Therefore, the conditions in the Punjab maynot be conducive to rust development.J. S. ChohanJ. S. Chohan supported the report and elaboratedthat the infestation has correlation withtemperatures that are very high in Punjab andHaryana and not conducive to the developmentof the pathogen.S. M. MisariHow soon do the detached leaves form rootsand become established? How long do thesedetached leaves last in this system? Is theresistance of detached leaves reduced? Haveyou noticed any nodulation on the rootsformed from detached leaves?D. J. Nevill(1) The rooted leaves can remain in goodcondition for 2 to 3 months.(2) No nodulation was observed in the rootsin the sterile sand.(3) No reduction in disease resistance wasobserved; there was a good correlationbetween disease rating in the laboratoryand in the field.(4) Roots begin to form after 10 to 14 days ofincubation.M. V. R. Prasad(1) Do you think that it is equally important toidentify the varieties that yield well despitethe incidence of leaf spot or rust diseases?Has any work been done in this direction?(2) I understand that some of the varieties ofgroundnut observed to be resistant atHyderabad do not maintain the same degreeof resistance at Dharwar. Do youthink that the collection of rust materialfrom Dharwar area would enable us toidentify some physiological races, aboutwhich data are scant at present?P. Subrahmanyam(1)1 agree. Work is in progress along theselines, and the subject was covered by Dr.Nigam yesterday. We now have foliardisease resistant lines that outyield nationallyreleased susceptible cultivarsunder unprotected conditions but, in mostcases, they are outyielded by the susceptiblecultivars when grown under a protectivefungicide regime.(2) I agree that we need to study the reactionsof the resistant lines at Dharwar as well asin many other locations. Such trials arebeing carried out and should give goodindications of whether physiological racesexist.C. HarknessIs there any relation between dry seed resistanceto A flavus and seedling resistance to Aflavus crown rot?J. S. ChohanThere does not appear to be any such relationshipand they appear to be independent ofeach other.P. Subrahmanyam, V. K. MehanAflaroot disease may originate from eitherseedborne or soilborne inoculum. Resistanceto invasion of pods or of seeds by A flavuscould reduce seedborne inoculum but wouldnot affect soilborne inoculum.We have found that some cultivars with good217

dry seed resistance to A. flavus colonizationalso possess measurable resistance to aflarootand crown rot, J-11 being an example, butthere is no evidence of a direct connectionbetween the two kinds of resistance.A. S. ChahalWhat about the dangers of the seedbornenature of Cylindrocladium in groundnuts?M. K. BeuteIn Virginia, Dr. Porter suggested the possibilitythat the pathogen could be seedborne. Seedfrom infected plants is small and usually willnot germinate. In commercial supplies ofseeds, such small seeds are rejected. Thus Ithink that thefungus is not spreading throughseeds in the USA and it is not I ikely to spread toIndia through seeds.M. A. Ali(1) Was the fungicide for Sclerotinia appliedto the soil or foliage?(2) How does the foliage-applied fungicidecontrol the soilborne pathogen's effect onroots, because the fungal invasion getsreplenished from the soil every time it isaffected by the chemical?(3) Why is the use of preemergence herbicidefound to be less effective than postemergenceapplied herbicide?(4) How many times did you have to usebenomyl as a soil dressing to controlSclerotinia blight (to Dr. Smith)?D. M. PorterThe fungicide was applied as a foliage spray.Foliage systemic fungicides can be washeddown to the soil and absorbed into the plantand protect the stem tissues from the pathogen.They are very active. The pathogen cannotbe eradicated in this way from the soil, butthe systemic fungicide will protect the plant.Preemergence herbicides were not effectivebecause they do not have a long-term effect.D. H. SmithI used benomyl only in a greenhouse experiment.In practice, benomyl is not used as a soilfungicide. It was demonstrated that the fungicidemoves upward in the plant if applied tothe soil. However, the foliar application did notshow any downward movement in the plant.The manufacturer did not feel soil applicationto be practical in a field situation.I. S. SekhonIn the ICRISAT 9-pointfield scale, when defoliationis above 50% a cultivar has to be scored9. For example, there is a lot of differencebetween the susceptibility of the two varietiesM-13and Faizpur 1-5. But with this scale, bothof these varieties had to be scored 9 at least atthe time of second scoring?P. SubrahmanyamDefoliation is only one among the differentparameters accounted for in the 9-pointscale. It needsto be taken into account with theother parameters.D. J. NevillDefoliation is a difficult parameter to measureand this is to be considered with other factorssuch as the season length of the variety. In ashort-season cultivar, there will be more defoliation,whereas in a long-season cultivarless defoliation occurs at the same time ofscoring.P. SubrahmanyamThe cultivars mentioned are of differentmaturity groups. Physiological maturity mustbe considered.J. S. SainiIn one of the slides you have shown that withthe fungicidal control of leaf spots the yieldincrease has been of the order of 230% overcontrol. What fungicide was used, at whatdosage, and what number of sprays weregiven?P. SubrahmanyamWe gave seven sprays of Daconil at the recommendedrates at 2-week intervals startingat the initiation of disease development.P. S. ReddyIt has been reported that the cultivar Robut33-1 is tolerant to the bud necrosis virus. Thesame cultivar has been reported to be highlysusceptible to thrips, the vector of this disease.Is there any explanation for this peculiar be-218

havior of this cultivar, i.e., it is susceptible tothe vector but resistant to the disease?P. W. AminRobut 33-1 is susceptible to the virus if it issap-inoculated. Thrips injure the leaves butvirus transmission or multiplication may notbe efficient. This is based on our field observationsonly. We have now initiated laboratorystudies to confirm these observations.V. RagunathanTo control the soilborne inoculum ofSclerotinia, is there any method other thanchemical control available that can be practicedby the SAT farmers? For example, organicamendments or calcium enrichment ofthe soil, etc.?D. M. PorterWe have looked at different cultural practiceslike (1) different seed rates, (2) different tillagepractices, (3) planting methods (such asturn rows), (4) spacing between the rows etc.,but we believe that none of these methods iseffective in controlling Sclerotinia. We havenot tried calcium, but we feel that the mostpromise lies in the identification of resistantvarieties.V. RagunathanCan green manure or any soil amendmentcontrol the disease — perhaps calcium?D. H. SmithRow orientation has been tried recently tostudy the effect of the sun and the wind ondisease development.D. R. C. BakhetiaIntercropping of pearl millet in groundnutdecreased the movement of the thrips vector.Did it result in any difference in the diseaseincidence transmitted by the thrips?A. M. GhanekarThis experiment is still in the field and we donot yet have complete data. However, early inthe season disease incidence was 20 to 25% inthe sole crop but only about 15% in theintercrop situation.R. W. GibbonsWould K. Middleton care to comment on themanagement of TSWV in Australia, particularlyon the cultural practices that have helpedto reduce the disease in recent years?K. MiddletonYes. TSWV is present in Queensland but doesnot produce the bud necrosis symptoms. Wecontrol this virus by management practices,particularly by controlling the alternate weedhosts. But the disease incidence can increasewith climatic conditions and under poor management.Weed control is important. Thereare a large number of alternate hosts. Therehas been as much as 70 to 80% diseaseinfection, but only in seasons with high weedpopulations.C. Raja Reddy(1) Does the screening technique take intoaccount very high vector pressure andBNV pressure, as the drawback of thecommon field screening technique quotedin literature is that it does not differentiatebetween resistance to vector and resistanceto the virus.(2) Variation has been shown to the vector —two biotypes in respect of BNV. Is thereany strain variation in BNV?D. V. R. ReddyRobut 33-1 and NC Acc 2757 were tested underhigh disease pressure. Perhaps Dr. Amin cantell us about the vector pressure.P. W. AminThe susceptible cultivar TMV-2 showed 70 to80% disease while Robut 33-1 showed 20 to50% disease under similar high vector pressure.D. V. R. ReddyWe have examined virus isolates from differentplaces but did not detect any variation.M. P. Ghewande(1) What was the percentage incidence levelof BNV under 37.5 x 5 cm and 150 x 15cm spacings?(2) If it is the case that closer planting reducedthe incidence of BNV, what could be thereason?219

(3) In India, row-to-row spacing normallyadopted is 30 cm or 45 cm, except in theSaurashtra area of Gujarat where it is 90cm. Why did you try such a wide spacingas 150 cm?A. M. Ghanekar(1) For the cultivar TMV-2 in the 1979 rainyseason, the closest plant spacing (37.5cm x 5 cm) resulted in 48.7% bud necrosisinfected plants while the wider spacing(150 cm x 15 cm) gave 94.0% diseasedplants.(2) Closer planting reduced the percentageincidence but not the actual numbers ofplants infected on a unit area basis.R. W. GibbonsRecommendations are always for narrowerrow spacings but how often are they followedby the farmers? The same recommendationswere madef or rosette control. It is the result ofpoor extension of research; that needs to beimproved. Most farmers do not follow extensionwork recommendations.S. H. PatilThe management recommendation to sowearly for reducing the incidence of bud necrosisin the rainy season is not practical. In thisseason, sowing can be done only after therains have started. Similarly the rabi (postrainyseason) sowing in October is notpracticable in India as the fields will not beready for sowing. You are aware that the rabigroundnut occupies mostly the paddy fallows.Your observations may be of scientific valuebut not practicable.D. V. R. ReddyEarly planting in the rainy season means assoon as sufficient rain has fallen. Very oftenthe farmer does not do this.S. H. PatilIn Maharashtra, delayed plantings in Januaryreduced the disease incidence; we got 30% inDecember planting and 10% in January plantings.P. W. AminThe disease incidence depends on the migrationof the thrips rather than early or lateplantings. Our results are from AndhraPradesh, and the thrips invasion may varyfrom area to area. There is a need to do moretrials over more varied ecological zones.220

Session 8Country ReportsChairman: R. W. GibbonsCo-Chairman: J. P. MossRapporteurs: A. M. GhanekarP. T. C. NambiarS. N. Nigam

Groundnut Production, Utilization, ResearchProblems and Further Research Needsin AustraliaK. J. Middleton*ProductionCommercial groundnut production in Australiais centered in two distinct areas in the state ofQueensland. Total planting in recent years hasbeen 32 000-36 000 ha with production rangingfrom 32 000 to 62 000 tonnes. There is no governmentcontrol over the area planted. An erect,large-seeded Virginia type, known as VirginiaBunch, is planted on 75-80% of this area, andSpanish types are sown on the balance. TwoSpanish types are grown— a red-seeded cultivarof uncertain origin, and a pink-seeded typewhich has been introduced recently to theindustry. Approximately two thirds of the cropis grown in the traditional groundnut areas ofsouthern Queensland, while the balance isgrown on the Atherton Tableland and adjacentareas in northern Queensland, a region of rapidexpansion.In Australia, groundnut production is highlymechanized, and heavily capitalized. Significantamounts of new technology have beenobtained from successful groundnut producingcountries, particularly the USA. In someinstances this technology has not been directlyapplicable, and some modification has beennecessary. This has been particularly noticeablewith harvesting procedures, largely because ofthe peculiarities of soil types used, and due tothe centralized marketing establishment.UtilizationGroundnut production in Australia is intendedfor the edible market, either as savory or con-* Plant Pathologist, Department of Primary Industries,J. Bjelke-Petersen Research Station, Kingaroy,Queensland.fectionery items, as peanut butter, or as ingredientsin baked biscuits (cookies), etc. Productionof oil is incidental to the production ofedible kernels. Consumption on the domesticmarket is slightly less than 30 000 tonnes ofedible kernels. Per capita consumption is low,relative to consumption in many other producingcountries. Any surplus over local demandis available for export, and substantial sales toNew Zealand, Hong Kong, Japan, Korea and theUnited Kingdom have been made in recentyears.Research ProblemsThe state-wide average yield of groundnut isalso low — approximately 1250 kg/ha; howeverthere are cases of yields exceeding 6000 kg/ha.These low yields, coupled with rising costs ofproduction (notably machinery fuel and pesticides)create the major difficulty in commercialproduction. Innovative research breakthroughsthat will improve yields and reducethe cost of production are urgently needed inthe peanut industry.Low average yields, with occasional highyields, are explained by limitations in the availabilityof water to the crop. Practically allAustralian groundnuts are grown without thebenefit of irrigation because significantamounts of suitable water are not available.Average rainfall during the growing season inthe southern growing area is 500 mm; variabilityis high. In the northern area, 1300 mm isnormal during the growing season, and thisexplains the recent increase in production inthis area. The cultivars grown exhibit droughttolerance, and this trait must be retained in anycultivar used in the future.The soils used for most of Australia'sgroundnut production are friable clays. They223

have better moisture holding capacity than thesandy soils commonly used for the crop. However,crop yields appear to be insensitive toinputs of technology such as introduced cultivars,nutritional improvement, disease controland tillage innovations, so that the improvedyields experienced in some other countrieshave not occurred in Australia. The occasionalhigh yields referred to above are usually fromcrops grown on land being returned to cultivationafter a period under pasture. This wouldsuggest that the physical state of the soil islimiting production, and together with thelimited amount of rainfall, is a factor affectingthe supply of available moisture to the peanutplants. Also, there are indications that aninteraction exists between soil physical conditionsand nutrition, soilborne disease, andharvesting losses. It has been determined thatsymbiotic nitrogen fixation by the crop isadequate. The complex of soil physical conditions,moisture, nutrition and disease is thesubject of a research program commencingwithin a few weeks, based at the J. Bjelke-Petersen Field Station, at Kingaroy.Diseases also limit yields and/or increasecosts of production. A serious problem undoubtedlyassociated with drought conditions is theoccurrence of aflatoxins in the harvestedcommodity. Maximum efforts to reduce postharvestdevelopment of aflatoxins have highlightedthe importance of preharvest contaminationby alfatoxins in seasons when theproblem assumes real significance. As such,irrigation or other drought mitigation proceduresare not available. It appears that the mosteffective way to control aflatoxin contaminationis by host resistance. A pathologist is currentlyworking to demonstrate the degree of associationof aflatoxin accumulation with biotic,climatic, and cultural conditions. Quantificationof the importance of these factors will enable areasonable prediction to be made of the likelihoodof serious aflatoxin contamination.Seedling diseases, especially crown rot andpreemergence rot, have been adequately controlledsince the introduction of captanquintozeneseedtreatment. However, proposedutilization of aflatoxin contaminated material asseed coupled with some expansion of thegroundnut crop onto sandy soil under irrigation,has demonstrated a possible inadequacyof captan-quintozene dust treatment to controlseed-borne Aspergillus flavus. The recent developmentof a waterless flowable formulationof organic fungicides will be tested as seedtreatments for control of this problem.The stem, peg and pod rot caused by the soilinhabitingfungus Sclerotium rolfsii is a majorcause of reduced yields. This disease can causelosses of 25% or more, and attempts to controlthe disease with chemical treatments or culturalpractices (e.g., deep turning) have been unsuccessful.There is a suggestion that the disease isworse when soil conditions are conducive tomoisture stress and low yields. The influence ofthose soil conditions, which produce poor plantgrowth and production, onS. rolfsii occurrenceand severity may provide a clue to control ofthis disease, possibly by biological means.Another cause of yield loss and increasedcost of disease control is the group of foliagediseases caused by Cercospora arachidicola,Cercosporidium personatum and Pucciniaarachidis, the early and late leaf spots andrust, respectively. The leaf spot diseases havebeen known for many years, but rust was notknown in Australia until 1973 when it was foundin north Queensland. It spread south in 1976,and is now present in all areas each year. Thesethree diseases are controlled by protectantfungicides, but the cost of such control is high,particularly where benomyl-tolerant strains ofthe late leaf spot pathogen occur. Currently,control measures are aimed at optimizing diseasecontrol with minimum cost, includingreducing the number of applications wherepossible and improving the efficiency of fungicideapplications. The breeding programincludes screening germplasm for rust resistance,and will include leaf spot resistance whenpracticable..Net (web) blotch, Sclerotinia blight, Cylindrocladiumblack rot and Diplodia blight arerelatively minor diseases, but in isolated casescause serious losses. Net blotch can be controlledby some fungicides but the relationshipbetween environment and infection needsto bemore closely studied to enable growers toadjust applications accordingly. This relationshipis being investigated. Chemical control ofSclerotinia blight appears possible, but the costof the practice is not yet known. The effect of soilphysical conditions on the ecology of Diplodiaand Sclerotinia should be studied to gain anunderstanding of disease development and to224

enable effective control measures to be found.To date, nematodes have not been a consistentproblem in traditional peanut soils, butextension of the industry into lighter soiltypes may cause problems. Virus diseaseshave caused little commercial loss to date. Thestrain of peanut mottle virus present throughoutthe peanut area causes only a slight loss inexisting cultivars. Tomato spotted wilt virusseriously affects yields, but adequate weedcontrol provides sufficient protection byminimizing the number of plants infected.In summary, low yields and high costs ofproduction are features of the Australiangroundnut industry, and are consequences oftwo factors: (1) the unreliability of rainfall inmuch of Queensland and (2) the high cost ofcontrol of crop pests, particularly diseases andweeds.Future Research NeedsThe unreliability of rainfall has forced growersto use a specific soil type, sufficiently friable toallow harvesting, but at the same time providinga degree of drought insurance. The soil typeused has resulted in a need for nutritionalresearch, including investigations of Rhizobiumspp. The soil type being used appears to havedeveloped one or more physical conditionswhich contribute to low yields, to increaseddisease development, and to soil erosion. Thesoil type, and its erosion potential, have stimulatedstudies of tillage methods. This researchinvolves the development of machinery suitablefor production practices without destroyingpreceding crop residues.A plant breeding program is also under way toimprove yields, as well as to control diseases,while maintaining drought tolerance and marketcompetitiveness. This will produce newcultivars, some of which might be a differentbotanical type to those currently being used. Itmight be necessary, therefore, to adopt newmachinery capable of handling such cultivars.New machinery inputs will continue as improvedpest control using more effectivemethods of pesticide application are developed.In addition to the control of diseasesby breeding for resistance, supplemental diseaseand weed control measures will continueto be necessary. Insects are not a problem. Anintegration of agronomy, breeding, soil conservation,engineering and pathology is needed tofind answers that will improve yields andminimize production costs. A multidisciplineresearch team has been formed within theDepartment of Primary Industries at Kingaroy,and in North Queensland. The potential ofgroundnut oil as an alternative fuel for compressionignition engines might provide theincentive needed to carry this research throughto a successful end.225

Groundnut Production, Utilization, ResearchProblems and Further Research Needsin BangladeshM. A. Hamid*Bangladesh is predominantly an agriculturalcountry and 85% of the population depends onagriculture. There is a need to become selfsufficientin food and to produce sufficientquantities to support agro-based industries,and also to earn foreign exchange.A recent report (Rahman et al. 1976) indicatedthat an adult in Bangladesh requires 53 g ofprotein/day but at present the per day consumptionof a man is only 8 g. The annual edible oilrequirement at the present supply rate of 1.1kg/capita per annum is 82 500 metric tons. If thereasonable rate is fixed at 2.2 kg/capita perannum, the annual requirement then becomes165 000 metric tons, but at present Bangladeshis producing only 54 910 metric tons, mainlyfrom mustard and groundnut. This huge deficitis being met either by importing oil or oilseedsfrom abroad and thereby using hard-earnedforeign exchange.ProductionBangladesh produces eight types of oilseeds ofwhich mustard, rapeseed, sesame andgroundnut are the principal ones. The acreage,production and yield of groundnuts are shownin Table 1. Groundnut produces more thantwice theyield of sesame and mustard (Table 2).Groundnut can be grown throughout theyear. Land preparation requirement forgroundnut is more or less equal in highlandcompared with mustard and rapeseed, but in"charlands", (very sandy or sandy loam soils),land preparation is less. Groundnut is not influencedvery much by environmental variations.The nitrogenous fertilizer requirement is not* Scientific Officer, Institute of Nuclear Agriculture,P.O. Box 4, Mymensingh, Bangladesh.Table 1. Groundnut area, production, andyield/acre In Bangladesh.Year Area (acres) Production Yield/acre1969-70 80 51 17.51970-71 78 46 16.21971-72 66 36 15.01972-73 57 31 14.91973-74 51 28 15.11974-75 48 26 14.91975-76 55 31 15.51976-77 52 23 12.11977-78 58 27 12.8Source: Bangladesh Bureau of Statistics 1979 (Ministry ofAgriculture).Note: Area In thousand acres; production Jn 1000 long tons;yield/acre = maunds/acre; one ton = 27.438 maunds;one maund - 82 lbs -37.25 kg.great mainly because symbiotic bacteria livingin their roots fix atmospheric nitrogen.The most important point in favor ofgroundnut cultivation is the utilization ofcharland where no economic crop can begrown except sweet potato, watermelons andmassmelons. The groundnut yield/acre inBangladesh is one of the lowest in the world(Table 3) but the economic return is more fromgroundnut than other oilseed crops.Climate and SoilGroundnut thrives in high temperatures (25-30°C). The daily water requirement is about 0.21acre inches which equals 26.1 acre inches for itstotal need (Arakeri et al. 1967). Water needs aremainly met by rainfall. The areas receiving42-54 inches of rain are suitable for its cultivation.Although groundnuts can be grown through-226

Table 2.Seed yield and expected oil and protein yields from different oilseed crops in Bangladesh.Yield/acre (mds)Yield/acre (mds)Oil (commercialCrop Yield/acre (maunds) Oil (%) Protein (%) Oil Protein extract able)Groundnut 16.0 42.2 26.0 5.50 3.40 4.2Sesame 6.3 47.0 20.0 4.01 1.26 2.5Soybean 15.0 22.0 42.0 3.03 6.03 3.0Rapeseed a nd 6.1 38.2 27.0 2.31 1.65 2.0mustardOne maund = 82 lbs = 37.25 kg.Table 3.Yields of groundnut (in shell) inBangladesh and other countries.with highlands the number of soil workingsmay be greater.CountryYield/acre (maunds)Bangladesh 15.0Mauritius 47.1Israel 39.0Greece 31.4USA 30.3Source: Food and Agriculture Organization (FAO) 1974.One maund - 82 lbs - 37.25 kg.out the year, their cultivation is more profitablein the rabi season — mid-September to mid-March.The crop can be grown in all thesoil tracts, butit is mostly grown in charlands, which areavailable adjacent to the rivers. Such soils arewell drained, light colored, sandy to sandyloams with adequate calcium. Dark coloredheavy soils stain the hulls which lowers themarket value of the crop. The cultivation cost ishigh in heavy soils and they give a comparativelylow yield which may be due to unsatisfactorypenetration of the pegs into the soil and thefailure of nuts and seeds to develop properly.CultivationGroundnut is a clean tilled crop that needsdeep plowed friable soils. Two to three crossplowings followed by two or three harrowingsare generally practiced in charlands, butPlanting TimeA favorable yield and a harvest before the startof the monsoon are obtainable if the winterplanting is sown within the first fortnight ofNovember. In summer, the crop is planted inJune in highlands with well drained soil.FertilizersGroundnut mainly requires N, K, P, and Ca. Itsnitrogen need is comparatively less due tosymbiosis with Rhizobium. The phosphorusrequirement is high as it helps in developingbetter quality seed with a high oil content. Hongand Van Schuylenbourgh reported the role of Kas a maintainor of high quality seed. Calciumhas been found to affect the shelling outturn ofthe seeds — a vital requirement for higheryield. Copper and Boron have a positive responseon yield, but their application may notbe possible in Bangladesh and it is better toapply organic manure.Hobbs (1976) reported that groundnuts makea heavy drain on Ca and gypsum is effective toimprovetheshelling outturn. Moreover, it helpsto reduce the number of pops and empty pods.Khan and Rahman (1968) observed inBangladesh in alluvial soil that the applicationof N, P and K in a ratio of 20:40:40 lbs/acreproduced a high yield and oil content, whileQuader and Islam (1964) reported that theapplication of N, P and K in the ratio of 20:60:60lbs/acre gave a good yield in red soils.227

Seed RateGroundnut may be sown with or without shell.Experiments conducted in different countrieshave indicated that germination is very low ifthe shells remain with seeds. Plant population/acre is an important factor for yield of nuts.Khan and Rahman (1968) and Quader andKhaleque (1966) using the variety Dacca-1,found that nut production was maximum withan area of 90 sq. inch/plant — 10 inches x 9inches and 15 inches x 6 inches. Other workershave concluded that 12-15 inch row width anda 4-6 inch spacing between plants were favorablefor high yields.For spreading types, 20-24 inches betweenrows and 9-12 inches between plants in a row isfavorable. Bunch type groundnuts (mostlygrown in Bangladesh) require a spacing of 15inches between rows and 6 inches betweenplants in a row, thereby accommodating approximately69 696 plants/acre. It has beenfound that 80-90 lbs of unshelled nut willprovide the desired plant populations per acre.Cultural OperationsGroundnut can withstand the average droughtconditions in this region but an irrigation at firstflowering favors yield. One weeding after 30days and another at 45-50 days after sowing isgenerally required. For easy penetration ofmaximum pegs, a layer of 2-3 inches is generallyraised up just before the maximum flowersare going to flush.DiseasesCercospora leaf spots and Sclerotinia blight arethe principal diseases. Aspergillus flavus attacksstored seeds and produces aflatoxin.Jalaluddin (1977) reported that Dithane M 45and copper oxychloride increased yield by 50%and 16%, respectively, when sprayed againstfungal flora.M a j o r PestsThese are hairy caterpillars and subterraneanants. The latter are very serious in highlandareas and they cause wilting. Leaf rollers andaphids are also commonly found.UtilizationGroundnuts are used as roasted nuts, saltednuts, blanched nuts and in making candies,cakes and cookies.Edible oil is extracted. In 1976, an oil mill wascommissioned in the District of Mymensingh. Ithas a present capacity of 50 metric tons/dayfrom which 15 metric tons of oil/day can beproduced. The groundnut oil mill does not run atfull capacity throughout the year due to aninsufficient supply of groundnut. The oil is usedin making soaps.In charland areas of Bangladesh, groundnuttops are used as hay and silage after the harvestof the nuts.Research and ResearchProblemsResearch work on oilseeds and pulses wasstarted by the Bangladesh Agricultural ResearchInstitute (BARI) about 1957-58. BARIhas recommended two groundnut varietiesselected from local and exotic sources. TheInstitute has also collected some exoticgermplasms and had undertaken limited varietyand agronomy trials.The Institute of Nuclear Agriculture (INA) inMymensingh has conducted groundnut irradiationbreeding with the local recommended varietyDacca-1. Some selections of desirable typesare now in the Msgeneration. About 40 varietieshave been collected from India and they arebeing studied for adaptability and yield performance.A little work on the selection of high yieldinggroundnut lines has been attempted at theBangladesh Agricultural University.The Bangladesh Agricultural Research Council(BARC) completed a survey on the position ofgroundnut production and utilization inBangladesh in 1976 (Anon. 1976). This reportalso dealt with socioeconomic conditions inthe industry and these findings included: 22%groundnut farmers are old, 48% are middleaged and 30% are young; 67% have had noeducation and 17% and 13% have received onlyprimary and high school education, respectively;the average farm size was 4.68 acres(range: 0.25-21.50 acres); 98% of the farmersowned their land; 98% procured their seed from228

themarket; 100% sold their produce in the localmarket; and the low and medium income groupof farmers consisted of 40% and 39%, respectively,while the high income group amountedto 21%.The study also examined the extent of adoptionof the principal farm practices and it foundthat the use of seed treatment chemicals andfungicides was nil; only 22% of the farmersused manures and fertilizers; 36.7% followedearthing-up practices; 0.16% irrigated theirfields and only 4% used insecticides.Problems of Groundnut CultivationLow yield is the main problem which is mainlydue to the low genetic potentiality of the cultivars,heavy disease infestations particularlyfrom Cercospora leaf spots (both early and late)and Sclerotinia blight, insect infestations, lowlevels of fertilization, no irrigation facilities,inability of the farmers to procure timely andadequate quantities of the required inputs, andfarmer ignorance of the extent of damagecaused by diseases, insects and inadequatefertilizers.Further Research NeedsThere are many requirements. They include theintroduction of adequate germplasm; studieson its adaptation; selection of germplasm andbreeding for high seed yield with high oil andprotein content; resistance to diseases andinsect pests; high N fixing ability and adaptabilityto varying soils and climatic zones; researchto develop suitable inocula; and research onseed viability sothatf armers can keep their ownseed for the next planting.ReferencesANON. 1976. Survey on the present position ofgroundnut production and utilization inBangladesh. Bangladesh Agricultural Universityand the Mymensingh and Bangladesh AgriculturalResearch Council.ARAKERI, H. R., CHALAIN, G. V., SATYANARAYANA, P., andDONAHUE, R. I. 1967. Page 445 in Soil managementin India. Asia Publishing House, Bombay, India.HOBBS, P. R. 1976. Page 5 in The ADAB News.HONG, G. B., and VAN SCHUYLENBOURGH, J. Page 146 inFertilizer use by JACOB, A. and DEXKULL, H. V., Thirded.JALALUDOIN, M. 1977. Thesis, Bangladesh AgriculturalUniversity, Mymensingh.KHAN, I. H., and RAHMAN, L. 1968. Pakistan Journal ofBiology and Agricultural Science.QUADER, M. A., and ISLAM, W. 1964. Thesis, Faculty ofAgriculture, University of Dacca.QUADER, M. A., and KHALEQUE, M. A. 1966. Thesis,Faculty of Agriulture, E. P. Agricultural University,Mymensingh.RAHMAN, A. T. M., and MATIN, M. A. 1976. DainikBangle, Dacca.RAHMAN, L 1970. Groundnut, a promising oil crop inEast Pakistan (now Bangladesh). Pakistan Journal ofScience 22: 34.229

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in BurmaU. Win Naing*Local spreading groundnuts have been sown inBurma since 1880. They are two seeded andthree seeded pod types. The seed color is pink.During the year 1925, some exotic spreadinggroundnuts were introduced into Burma andafter five years of selection, the cultivarM-30/38 was produced.Erect groundnuts named Small Spanish, BigSpanish, Small Japanese, and Big Japanesehave been grown in Burma since 1920. Later,more exotic erect groundnuts were introducedinto Burma and aftersomeyears of selection SP121/070 was produced at Magwe Central Farm.Distribution to farmers commenced in 1948 andlater it became very popular and spread all overBurma. Some years later, the erect varietiesM-9, M-10, M-11 were produced.ProductionThe area sown to groundnuts fluctuates (Table1). The highest acreage sown was in 1973-74when it was 1 973 470 acres. The lowest was1132 300 acres during 1966-67. The maincauses of the fluctuations are the frequentoccurrence of unfruitful rainfall in thegroundnut areas and the very high price of seedgroundnuts in some years.between SP 121/070 and S.550-05; and M-11 is aselection from Shawat 21/6.The characteristics of varieties grown inBurma are shown in Table 2.Main Factors Affecting YieldOver 50% of the total area of groundnut is sownas raincrop, under semi-arid region conditions.The rainfall pattern during the crop growingseason favors a fruitful harvest only one year inten. Sometimes there are 25-40 days betweentwo precipitations.Winter groundnuts are sown on the fertileriverine sides and islands along the Irrawaddyriver. Here the yield rate is 50-100% higherthanrainfed groundnut on upland.Only a few acres of the total area are fertilizedwith farmyard manure, urea and triple superphosphate(Table 3).UtilizationGroundnut oil and sesame oil are the maincomponents used for cooking. Because Burmeseoil consumption consists of 70%groundnut oil, there is little increase in productionof groundnuts for kitchen consumption.VarietiesThe following varieties are grown during therainy and winter seasons:Rainy Season: (1) Erect Type: SP 121/070,M-9, M-10, M-11, and Small Japanese; (2)Spreading Type:- M-30/38, AH-35, KhaungonSpreading, and local spreading.Winter Season: Erect Type: SP 121/070, M-9,M-10, and M-11. The line M-9 is a selection fromSP 121/070; M-10 was produced from a cross* Agriculture Corporation, Rangoon, Burma.Research ProblemsThere are many problems in groundnut cultivationin farmers' fields as well as in the experimentalstations of the Agricultural Corporation.To conduct the appreciable amounts of requiredexperiments, the Agriculturral Corporationwith the help of UNDP has increased thenumbers of farms as well as research facilitiesand technicians.In Burma there are two central experimentalstations and five seed farms which are conductinggroundnut experiments.230

Table 1. Area and yield of groundnuts in Burma.Sown Matured Yield YieldYear acreage acreage lb/acre (25 lb basket)1975-76 1 693 337 1 633 769 554.5 36 229 4281976-77 1 507 304 1410 357 661.0 37 289 2801977-78 1 418 263 1 391 822 735.0 40 946 2841078-79 1 421 840 1387 911 699.0 38 809 2161979-80 1 493 507 1 468 073 742.0 43 590 0001980-81 1 789 046 1 732 994 793.5 55 010 558(Projected)Table 2.Characteristics of groundnut varieties grown in Burma.Life period L B Midway Oil ShellingVariety Plant type (days) Seed color (mm) (mm) girth(mm) (%) (%)SP 121/070 Erect 110 Pink 24.7 10.6 9.5 47 71M-9 " 110 25.4 10.9 9.6 59 73M-10 " 110 22.9 10.4 10.0 54 76M-11 " 110 23.5 13.5 10.0 55 75M-30/38 Spread 150 21.6 10.2 9.0 49 70Kyaungon " 150 23.2 9.9 9.3 49 68Local " 170 27.0 13.2 11.2 49 70spreadingPodThe following types of experiments are beingconducted on these farms in 1980-81: Table 3. Fertilizer usage in Burma (1955—861.2.Varietal yield tests.Rhizobium inoculation tests (mainly onto 1979—80, average).CB.756. Australian St.)Amount used Raincrop acreage3. Lime application and plant types.Fertilizer(tons)fertilized4. The effect of levels and carriers of phosphorus.Urea 4410200 000TSP a 2500120 0005. Residual effect of levels and carriers of Potash 250phosphorus on groundnut grown afterthe monsoon rice crop and after the a. TSP - Triple superphosphate.monsoon jute crop.6. Application of gypsum, nitrogen andphosphorus on erect groundnut.7. Depth of land preparation on erect Further Research Needsgroundnut.8. Insecticide effects on groundnut leafminer.Varietal Improvement9.10.Effect of weedicides on weeds.Effect of trace elements on groundnutyield.Presently six nucleus stock of erect types andfour nucleus stock of spreading types are maintained.For genetic stock, we have 70 erect231

varieties and 136 spreading varieties.Under selection, we have 45 Australian varitiesand 15 Japanese varieties, and in hybridizationwe have six crosses and 101 families.Maximum yield potential of the present varietiesused in cultivation is between 2500-3000lbs. The varieties should be improved to get themaximum yield potential up to 4000-5000 lbs.We have very few nucleus stock and geneticstocks. For proper selection and hybridizationpurposes, more exotic varieties should be introduced.Cultural PracticesCultivation in rows is usually practiced ingroundnut production. Spacings between rowto row and plant to plant are the prime factors.In most areas, 15 inches x 4 inches row x spacingfor erect groundnut and an 18 inches x 9inches row x spacing for spreading groundnutare practiced. Experiments should be conductedregionally to produce proper row xspacings.Uneven spacing and low seed germinationproduce poor results from hand drilling seeds infurrows. An improved seed driller, that givesprecise depth and distance, should be tested.Fertilizer ExperimentsWe have some fertilizer experiments ongroundnut at Magwe Central ExperimentalFarm. The last 3 years' experimental resultsgave little indication of nitrogen and phosphatefertilizer uptake. A significant nitrogen rate is 25lbs in combination with 35 lbs of phosphate atMagwe. We still have no significant indicationof the effect of gypsum on yield, but plantsseem to have a deeper green coloration. Experimentson yield with nitrogen and phosphatefertilizer at different rates should be conductedfurther in different regions.Since 1979, Rhizobium experiments havebeen conducted, but we have no significantresults. Experiments on yield with differentrates of gypsum and experiments withRhizobium strains should befurther conducted.232

Groundnut Production, Utilization, ResearchProblems and Further Research Needsin MalaysiaHalim B. Hamat and Ramli B. Mohd. Noor*Groundnut {Arachis hypogaea L.) is the mostextensively grown grain legume in Malaysia. Itis grown either as a sole crop in the riverine andrainfed rice areas, or as an intercrop especiallyin young rubber. It is an important cash crop inthis country. However, the hectarage has beenstable in the last few years. In 1976, the hectaragewas 5794 hectares in sole crop equivalent(Wong 1979). The major groundnut growingstates are Kelantan (2658 ha), Trengganu (1299ha), and Perak (1106 ha).Groundnut Production AreasAll the Malaysian groundnut crop is grownunder rainfed conditions. Generally, the growingareas are:Riverine AreaThis is mainly along the banks of the Kelantan,Trengganu, Perak, and Pahang rivers. The soil isalluvial and its fertility is replenished every yeardue to the annual flooding during the monsoonseason. This is the most intensive cultivatedarea and it contributes about 60% of the totalgroundnut production.Rubber and Oil Palm AreaThe groundnut is grown as an intercrop inyoung rubber and oil palm plantations, and insmall holdings. Such production is commonlyfound in the states of Perak and Selangor.Single Crop Rainfed Rice AreaHere the groundnut is grown in rotation withrice during the off season when a second crop is* Groundnut Breeder and Agronomist, respectively,of the Field Crops Branch, MARDI, Malaysia.not possible due to insufficient water. This is thepotential area for the expansion of groundnutcultivation. The areas are found in the states ofKelantan, Trengganu, Kedah, and Pahang andare estimated to be about 150 000 hectares(Wong 1979).Bris Soil AreaPresently a very insignificant hectarage ofgroundnut is grown in this area. However, it isanother potential growing area where thegroundnut can be rotated with tobacco. Thisarea is located along the east coast of PeninsularMalaysia.G r o u n d n u t G r o w i n g SeasonsMalaysia has an equatorial-type climate,characterized by humidity above 60%, abundantrainfall (200-300 cm/yr), temperaturesranging between 22°-31 c C throughout the year,and daylength of about 12 hours. Generally, twocrops of groundnut can be grown per year.In the East Coast states of Kelantan andTrengganu where 60% of the annual rainfalloccurs during the North-East Monsoon(November-March), 26% during the SouthwestMonsoon (May-September) and only 14%during the two transition months (April andOctober) (Dale 1974), the first planting (main)season begins in late January or early Februaryand the crop is harvested in April. The secondplanting season begins in late May or early Juneand the crop is harvested in September. Generallythe groundnut produced from the firstplanting season is of better quality than thesecond season (Anon. 1977).In the West Coast states of Perak, Selangorand Kedah where 36% of the annual rainfalloccurs during the North-East Monsoon, 4 1 %during the South-West Monsoon and 23% duringthe transition months (Dale 1974), the first233

planting season begins in April or May and thecrop is harvested in July or August. The secondplanting season begins in September orOctober and the crop is harvested in January.Generally, the hectarage is greater in the secondseason because the farmers grow more tocater for the demands of the Chinese festiveseason which occurs in February. Despite thissecond season being less suitable for the growingof groundnut than the first season due tohigher incidence of diseases, the selling priceis higher (Ramli et al. 1976).Although two crops of groundnut are possibleper year in most parts of the country, usuallyonly one crop is feasible if it is grown in rotationwith other crops. In the rainfed rice area of theEast Coast where it is rotated with rice, thegroundnut is usually planted in April or May andthecrop is harvested in August or September. Inthe Bris soil area where it can be rotated withtobacco, the growing season is also similar tothat in the rainfed rice area.C u r r e n t P r o d u c t i o n P r a c t i c e sA number of cultivars are grown by farmers. Inthe state of Perak, the most common cultivarsare Sungai Siput and Mengelembu, which aremainly marketed as roasted groundnut. Inother states, cultivars that originated fromIndonesia are commonly grown. PresentlyMARDI is recommending three cultivars —V13, Matjam and 47-5 — for growing throughoutthe country. They are of the Spanish bunchtype with small/medium two-seeded pods. Farmersusually obtain a yield of 3.0-3.75 metrictons of fresh pod per hectare, though a yield of 6t/ha has been recorded. The national averageyield is 2.2 t/ha and this is among the highest inAsia.In land preparation, generally either oneround of plowing and one round of rotovation,or two rounds of rotovations are practiced. Asquare planting of 30 cm x 30 cm with twoseeds per point giving about 220 000 plants/hais usually practiced. This requires approximately90 kg seed/ha. MARDI presently is recommendinga row planting of 50 cm x 10 cmwith one seed per point giving about 200 000plants/ha.Liming using dolomitic limestone at the rateof 1-2 t/ha and fertilizer at rates of 34 kg N, 56 kgP2O8 and 56 kg KaO in the forms of sulphate ofammonia, triple superphosphate and muriateof potash, respectively, are usually recommendedfor most soils. Liming is done duringland preparation at two weeks before planting,and fertilizer is applied at planting, in band.However, liming and fertilization are seldompracticed by the farmers especially in theriverine areas. If practiced, there is no standardrate of application. Usually a compoundfertilizer is broadcasted immediately afterweeding, one month after planting. Hilling ispracticed during the weeding operation.Insect pest and disease control is seldomcarried out because the problem is usually notserious. Disease like Cercospora leaf spot usuallyoccurs very late in the season and has littleeffect on the yield. However, if the diseaseoccurs early in the season, it can be effectivelycontrolled with benomyl fungicide.The groundnut is harvested 90 days afterplanting for use as roasted groundnuts andabout 105 days after planting for use as plantingmaterial.Costs of production and returns fromgroundnut vary greatly depending on the operationscarried out, yield and the current sellingprice. However, groundnut generally gives agood net return ranging from M$625 to 1000/haper season (Anon. 1977; Ramli et al. 1976).Groundnut Usageand UtilizationMost of the Malaysian groundnut production ismarketed as fresh, unshelled pods. They areused mostly for roasted groundnuts. Some areused for making cooking oil, oleomargarine,and confectionery. A special technique calledthe Mengelembu process has been developedfor roasting groundnuts. There are about tenfactories scattered all over the groundnut producingareas. Factories sometimes obtainadvance commitments by providing cash advancesand planting materials to selected farmers.Ex-farm groundnut prices vary accordingto locality, season and nut quality. The roastedgroundnuts are mainly consumed locally, butsome are exported to other countries.Research A c t i v i t yAt present, groundnut research activity is234

focused on breeding and varietal evaluation, developmentof cultural and management practices,nutrient requirement study, insect pest,disease and weed control studies.B r e e d i n g a n d V a r i e t a l E v a l u a t i o nVirtually all the past work on varietal improvementhad been varietal evaluation of foreigncultivars. After many years of evaluation, threecultivars were found to be high yielding. Theseare V13, Matjam and 47-5 and they arecurrentlybeing recommended to farmers. V13 is a localselection, Matjam originated from Indonesiaand 47-5 originated from Senegal. These threecultivars perform well throughout the country.Recently, a breeding program has been initiated.The breeding materials are evaluated atseveral locations in the groundnut growingarea. This is because the environmental conditionsand the problems of each area are different.The objective of the breeding program is todevelop high yielding cultivars for specificareas.To complement this program, germplasmfrom different ecogeographical regions is beingevaluated. Presently there are 256 accessions inour germplasm collection, of which 200 wereobtained from ICRISAT. Some of these accessionshave been included in advanceyield trialsover years and locations. A number of them arebeing used as parents in the breeding program.D e v e l o p m e n t o f C u l t u r a la n d M a n a g e m e n t P r a c t i c e sThere was limited work on cultural and managementpractices carried out in the past. Theinvestigations were mainly on plant spacing/density and harvesting time studies conductedon well-drained upland soils. Presentlygroundnut production has expanded to otherareas like the riverine, single crop rainfed riceand the Bris soil areas. Since each area offersdifferent ecological environments and productionproblems, there is a need to developcultural and management practices suitable foreach specific area.Nutrient Requirement StudiesSome work has been done on the nutrientrequirements of groundnut. The present recommendedrates of fertilizer application havebeen based on these findings. Since differentsoil types and locations differ in their nutrientstatus, nutrient requirement studies are requiredover many locations to determine optimumrates for each specific location. Alsothere is a need to study the inoculation requirementsof rhizobium bacteria for successfulnodulation so that the beneficial effects ofnitrogen fixation by these bacteria can beexploited and thus reduce the costs of nitrogenfertilizer application.Insect Pest StudiesIn recent years, research has been focused onthe identification of some of the more importantinsect pests and their chemical control. Some ofthe recommended insecticides are not as effectiveand also there have been reports of fieldresistance to some of the chemicals by theinsect pests. New chemicals, therefore, need tobe screened as a stopgap measure. Followingthe availability of effective insecticides, moreresearch should be devoted to screening forvarietal resistance. As part of a long termcontrol program, the role of natural enemiesalso needs to be investigated.D i s e a s e S t u d i e sMuch of the research effort on disease problemsover the years has been the identificationand diagnosis of the prevalent diseases. Chemicalcontrol has been effective for some diseases.However, for many other diseases, appropriatecontrol measures are still lacking orhave not been investigated. Perhaps the idealcontrol measure would be through varietalresistance. However, little has been done toutilize this attribute.Weed Control StudiesResearch on weed control in the past has beenconducted on well-drained upland soil. It hasbeen found that a preemergence application ofalachlor plus one round of manual weeding attwo weeks after planting is adequate for thistype of ecological environment. However, informationon weed control is lacking for theother groundnut growing areas. Weed surveysneed to be carried out to determine the major235

weed species in these other areas. Traditionally,weeding is done manually. Therefore, researchneeds to be conducted to determine the righttime and frequency to maximize crop yields.Also there is a need to screen other herbicidesand todetermine their efficacy to control certainprominent weeds.Further Research NeedsThe above research activities are those currentlybeing given priorities. However, we alsorecognize other areas where attention is requiredin order to promote the expansion ofgroundnut cultivation in the country. One sucharea that needs immediate attention ismechanization. Except for land preparation, allaspects of groundnut cultivation are done manually.Planting and harvesting are the two mostlaborious and time consuming operations. Inrainfed single crop rice and other low lyingareas, waterlogging is a constant problem. Toovercome it, the groundnut can be planted onridge or raised beds. Therefore, there is a needto develop a suitable and practical ridger orbedformer. In addition, fertilizer application andspraying to control weeds, insect pests anddiseases can also be mechanized. Attentionshould be given to mechanizing these operations.It has been recognized that groundnut cannotbe grown alone in an area, continuously.Groundnut cultivation needs to fit into a croppingsystem with other crops. It should bedetermined whether groundnut is suitable forcultivation after rice, tobacco and other annualcrops. Also, there is a need to know the benefitsof intercropping groundnut with other crops,whether they be annual or perennial.To further promote groundnut cultivation,there is a need to expand its usuage and utilizationin the country. The present groundnuthectarage is about to saturate the market forroasted groundnut. There is a need to look fornew ways of utilizing groundnut to make otherproducts.SummaryGroundnut is the most extensively grown grainlegume and it is an important cash crop in thecountry. However, the hectarage has been stablein the last few years. Previously, groundnutwas mainly grown in young rubber, oil palmand riverine areas, but now its cultivation hasexpanded to rainfed single crop rice areas. AlsoBris soil regions are another potentialgroundnut growing areas in the future. Generally,two crops of groundnut can be grown peryear throughout the country. However, if grownin rotation with other crops only one crop ispossible. Although there are recommendationsavailable for growing the crop many farmersseldom follow the recommended practices dueto socioeconomic problems. The crop is mainlyused for roasted groundnut.Research activities being currently emphasizedinclude breeding and varietal evaluation,development of suitable cultural andmanagement practices, nutrient requirementstudies, and insect pest, disease and weedcontrol studies. Our overall research objectiveis to develop technologies to obtain maximumyields for specific growing areas. In order topromote the expansion of groundnut cultivationin the country, further research shouldinclude mechanization, cropping systems andgroundnut utilization.R e f e r e n c e sANON. 1977. Groundnut cultivation in Kelantan. Page 6(In Malay, unpublished).DALE, W. I. 1974. The rainfall of Malaya, Part I. Pages132-144in The climate of West Malaysia and Singapore.RAMLI, M. N., ABU KASSIM, A. B., ABDULLAH, C. T.,and ZAINOL, A. A. 1976. Report on visit to Perakgroundnut growing areas (unpublished).WONG, L. J., ABDUL RAHMAN, D., JAAFAR, D., ZULKIFLY,Z., and XAVIER, N. 1979. Research towards farmingsystem in rainfed or single cropped rice area. MAROISenior Staff Annual Conference 11-13 Dec 1979(Mimeo).236

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in ThailandA r w o o t h Na Lampang, Terd Charoenwatana andDumrong Tiyawalee*There is no definite record about peanut introductioninto Thailand. However, it is believedthat peanut was brought into this country byEuropean traders during the Ayuthya period— about three hundred years ago. Peanut iswell adapted to tropical climate and at presentis cultivated in every part of the country. TheThai people consume nuts in various forms. Thearea (ha), production (metric tons), and yield(kg/ha) in the past decade are given in Table 1.The figures indicate an insignificant change inproduction during this period. Table 2 showspeanut production and consumption projectedfor the next 5 years.ProductionThe major growing regions are the North andCentral Plains, and the Northeast. In the South,heavy rainfall seems to limit large scale production.Nevertheless, isolated fields of peanut aregrown for local consumption, mainly in theyoung rubber replantations. Figure 1 illustratespeanut production in these four regions. Thelarge hectarage falls between latitudes 13 and20 degrees North.Soils suited for growing peanut are generallylight to medium texture and well drained.The Thailand climate is divided into twodistinct seasons — dry and wet seasons. Themonsoon or rainy season begins in May andlasts till October. This is the critical time for Thaifarmers since about 80% of the total arablelands depend mainly on this rainfall. The dryperiod covers the remainder of the year when* Director, Field Crop Division, Department of Agriculture,Bangkok; Vice Rector, Khon Keen University,Khon Kaen; and Dean, Faculty of Agriculture,Chiangmai University, Chiangmai, Thailand,respectively.crop cultivation, except in a small area, can beundertaken only with irrigation. This areaamounts to about 20% of the total cultivatedland. Thus peanut is grown in both seasons.Table 1. Area, production, and yield of peanut(In the pod) during the 10-year period(1969-1978).Area Production YieldYear (000 ha) (000 t) (kg/ha)1969 103 124 12061970 104 125 12001971 114 136 11691972 119 153 12881973 124 147 11811974 130 161 12371975 118 147 12061976 122 151 12441977 103 105 10311978 106 127 12061979 - 132 -Source: Office of Agricultural Economic Report 1960, Ministryof Agriculture and Cooperative.Table 2. Projected peanut production (In thepod) and consumption in the next5-year period (1980-1984).Year (000 t) (000 t) (000 t)1980 150 124 261981 159 127 321982 173 133 401983 187 138 491984 203 143 60Rate + 8% + 3.7% + 23%Source: Ministry of Commerce, 1980.237

Figure 1.Peanut production divided by regionsin the Kingdom of Thailand.Source: Office of AgriculturalEconomic Report 1978, Ministry ofAgriculture and Cooperatives.In the rainy season, planting is from May-June and harvest is in September and October,while in the dry season, planting is fromJanuary - February with harvest in March andApril, in paddy fields after rice.Since there is no specific requirement fortypes of peanut in the markets, the mediumseeded types are generally grown to satisfy amultipurpose demand. Three cultivars havebeen released to farmers at present. Two ofthem are Valencia type, S.K. 38, red seed coat,and Lampang, white seed coat, and one cultivarof bunch Virginia, Tainan 9, a white seed coat.They are well received throughout the country.However, the small seeded Spanish type isoccasionally seen in certain locations. Attemptsto grow large seeded Virginia runners have notbeen successful due to the longer duration andproblems of unfilled pods.Thai farmers grow peanut as mono or solecrops in the upland during the rainy season, andas mono crop followed by rice in the dry season. Aspacing of approximately 30 cm between rowsand 20 cm within rows does not permit intercropping.Recently, experiments on intercroppingof peanut with other row crops such ascassava, cotton, sugarcane and castor beanappear promising for practical development,based on LER (Land Equivalent Ratio).Peanut is less vulnerable to serious diseasesand insect pests compared with other legumes.Its relatively early maturity, about 110 days,allows it to escape severe attacks of Cercosporaleaf spot and rust which become serious andwidespread late in the rainy season. Seedling,stem and collar rots may occur during the peakof the rainy season, if land is not properlydrained. Leaf hoppers, rollers and miners createconsiderable problems during the dry period.Systemic insecticides are recommended fortheir control. Since harvesting of both the seasoncrops occurs in the dry periods, the aflatoxinhazard is minimized.Other factors which make peanut widelyadapted in Thailand are its ability to withstandintermittent moisture stress, low soil fertility,low pH and/or soil salinity as well as minimalmanagement. Also it can withstand atmosphericdrought for 2-3 weeks and resumegrowth immediately with good rains.Most Thai farmers treat peanut as a marginalcrop, especially in the rainy season. Hence,yields are low. In contrast, the Thai farmerprefers to grow peanut in the paddy fields,wherever irrigation is available, because of thevigorous growth of the following rice crops, inaddition to the extra income from peanut.Thailand imports considerable amounts ofunrefined peanut oil and cake, and exports bothshelled and unshelled nuts. Table 3 gives thetrade balance during 1975-1979 and Figure 2shows sharing relationships between thefarmer, dealer, shelter and exporter.238

UtilizationPeanut utilization in Thailand is relatively similarto that in other countries. There are numerousforms and preparations employed in theprocesses to obtain the finished products startingwith either the whole pod or shelled nuts.Whole Pod (Unshelled)BOIL. Fresh pods from the fields are boiled orsteamed, and a small quantity of salt is added asflavoring. The cooked pods are drained out andimmediately put on sale as snack. This kind ofpreparation is simple and popular to streetretailers or vendors.BOIL AND DRY. The above products cannot bekept for a long time. Processors have to dry thecooked pods under sunshine and/or in the ovento reduce the moisture content in the pods to acertain limit. They are packed in airtight plasticbags to prolong their keeping quality. Thailandrecently started to export this type of product toneighboring countries. There is a continuouslyincreasing demand.ROASTED PEANUTS. Large and medium podsare sorted out from the dry bulk. Then they areroasted, usually with hot sand. The product isvended directly and/or kept in plastic bags fortransportation to other places.Shelled NutsPeanut is generally stored in the pod. At theSource: Ministry of Commerce 1980.Figure 2. Shares in peanut exportation(based on 1980 data).processing plant, the pods are shelled and nutsare removed from the shells or hulls. The nutsare graded into three classes according to theirsizes:LARGE AND MEDIUM SEED SIZES. These aremainly used in the form of whole nuts and theycommand premium prices. They are preparedfor snacks by deep frying, roasting and/or bakingand for making confectioneries and desserts.SMALLANDBROKEN NUTS. These are ground ormilled to make peanut meal. The meal isconverted into pastes, curries, desserts andseveral forms of snacks.Table 3. Balance of peanut trade during the 5-year period (1975-1979).YearImport(as podsProduction(dry pod, 000 t) (000 t) Million βExport(as pods)Dom Consump.(000 t) (000 t) Million β1975 142 30 36 133 9 861976 151 92 100 140 12 941977 105 95 149 82 24 1661978 127 26 33 92 36 2061979 131 29 46 117 15 104Source:Note:Custom Department, Ministry of Finance, 1980.1 U.S.S = 20 β239

OIL EXTRACTION AND FEED M E A L Due to anincreasing demand for edible oils and animalfeeds in the past decade, oil extraction industrieswere established to extract peanut andother edible oils. However, peanut costs considerablymore than other sources of oil such assoybean and rice bran. At present, peanutsenter the trade mainly for human consumptionin both the domestic and foreign markets aswhole nuts.To a lesser extent, peanut is used in specialforms, such as fermented paste and sprouts.The feed industries used to import peanutcake in large quantities as a substitute forsoybean cake. The restriction of aflatoxin imposedin the last few years has led to a considerablereduction of imports.Research ProblemsThe Thai government is planning to increasepeanut production for both domestic consumptionand export. The attention to and investmentin this crop is inadequate at present,especially from the research standpoint. Thereare several constraints to be removed beforehigher levels of yield can be obtained.In regard to varietal improvement, thefollowingcharacters are needed — high, reliable,consistent yields; earliness (i.e., about 90 days)to fit existing cropping patterns; uniform flowering,pod setting and maturity; resistance tomajor pests and diseases, including Aspergillusflavus; and higher shelling percentage.Research is required on cultural practices andcropping systems to minimize labor and otherinputs, obtain higher LER, maintain soil fertility,and to spread the farm labor requirement andthereby reduce peak demand. Small and animaldrawn equipment such as the planter, poddigger, pod picker and shelter need to be researched.Constraints imposed by diseases, insectpests and weeds constitute important problems.Further Research NeedsIncreased research on peanut is urgentlyneeded in order to increase yield per unit areaas well as the national product. The goals forfurther research are:1. Develop larger seeded varieties with ashorter growing season.2. Study the peanut cropping system in therainfed areas, which occupy about fourfifthof arable lands in the Kingdom. Attentionmust be paid particularly to the Northeast,where soils are relatively infertile andrainfall is erratic.3. Improve or maintain soil productivity bythe application of rock phosphate andother sources of phosphorus (in additionto Item 2).4. Research on minimizing aflatoxin contaminationby means of breeding, culturalpractices, storage and detoxification bychemical treatment.The above goals require a strengthening ofresearch facilities involving (1) staff training inshort term and academic programs, (2) coordinationat international and national levels withpeanut research institutes in the exchange ofgermplasm, seeds, materials, information andresearch results, and (3) the establishment ofregional yield trials.240

Groundnut Production, Utilization, ResearchProblems and Further Research Needsin ArgentinaJose R. Pietrarelli*ProductionFor the past fifty years, groundnut cultivation inArgentina has been concentrated in the centralregion of Cordoba province and in eight departmentslocated therein. During this period,small areas have been sown in other provincesof the Northeast, Northwest and ArgentineLitoral. However, they constitute only 2-3% ofthe total area of the country with 97-98% of thetotal sown hectarage being located in C6rdoba.Since 1970, the average area harvested hasbeen 346 125 hectares per annum with an averageannual production of 280 787 metric tons ofshelled groundnut, which represents an averageannual yield of 811 kg/ha. The sowingrecord in this past decade was 428 000 hectaresin 1977-78. In the 1978-79 season, only329 000 hectares were cultivated while in1979-80, only 281 000 hectares were harvested.International markets, lower prices andless demand by the oil industry are expected tocause a further reduction in the area sown togroundnut.Cordoba Region ProductionCharacteristicsThe region is furrowed by the First and Secondrivers which run to the northeast, and by theThird river which flows to the southeast.The soil is generally classified as brown, isdeep and is without much impermeable covering.The texture is sandy loam. The alluvialssituated in the regions are sandy. Soil organicmatter content varies and it averages about 2%.The soils are well supplied with calcium, mag-* Agronomist, INTA, Manfredi Research Station,Manfredi, Argentina.nesium and potassium but the levels of nitrogenand phosphorus range from moderate tolow. The ground surfaces utilized are mostlylevel. In a few cases, the slope varies from1 to 3%. The soil type is such that the land iseasily eroded by wind or rain.The region is semi-arid. Rainfall ranges from600 to 800 mm annually and falls generally betweenOctober and March. There is great variabilityin the time, amount and rainfall distributioneach year which results in yield variations.The coldest month is July, with an averagetemperature of 9-10°C. The hottest month isJanuary, with an average temperature of 23-24°C. The frost free period is 245 days. Frostsnormally occur in May but in some years maycommence in April. Because rain falls in thespring and summer seasons when highertemperatures occur, groundnut can be successfullycultivated in the Cordoba region.Sowing is favored with a spring which issufficiently humid in order to plant thegroundnut in November or the first days ofDecember. The fall-winter period is dry enoughto permit harvest and natural drying of theproduct under good conditions. The areas sownrange from 100to 150ha. Minifunds exist whichallow a medium extension of 50-100 ha.The monoculture areas are located on thesides of the Second and Third rivers. Themonoculture of groundnut is characterized by asecurity of cropping.Agricultural EquipmentIn the Cbrdoba region, there is a high degree ofmechanization. Equipment is used for tillage,sowing, cultural practices and the applicationof herbicides and fungicides. The equipmentusually consists of plows of 4 or 5 colters,harrow-plows, teeth-harrows, rotary hoes,sowing machines for small and large grain (up241

to seven rows), and rowing rakes of lateraldischarges, etc.About 30% of the growers have diggershaker-windrowmachines, and 20% havetillersor peanut combines. Growers who do not possessthese last named machines, employ contractors.HarvestAbout 90% of the area cultivated withgroundnut is harvested with a digger-shakerwindrowerwhich works from 3 to 5 rows. Thatsame percentage is picked with a peanut combine.The rest of the production is prepared witha stackpole, especially in the monocultural area.Principal VarietiesThe cultivars grown in the Cordoba regionbelong to Arachis hypogaea, subsp fastigiatavars fastigiata and vulgaris. Colorado comunand Blanco Rio Segundo are the most extensivelyused cultivars (about 50%;. These twovarieties were present prior to the commencementof varietal improvement (breeding) at theManfredi Experimental Station. Their cultivationmust be very old. They are perfectlyadapted to the ecological conditions of thecentral region of Cordoba.Other varieties sown in this area are allproducts of the Manfredi Experimental Station.Colorado Manfredi was obtained by selectionfrom Colorado comun, and occupies 5% of theplanting area. Blanco Manfredi 68 originatedfrom the crossing of a black groundnut (type 4)with a Virginia type line (Fla. 249-40-B3). Itoccupies 15% of the area. Colorado IrradiadoINTA comes from a mutation induced by X-raysin the variety Colorado Manfredi and it occupies20% of the planted area.The other varieties — Colorado CorrentinoINTA (a selection from a population grown inthe province of Corrientes), Blanco Asuncion(a selection from a population grown inParaguay), Manfredi Virginia 3-INTA (agenealogical linefrom North Carolina, USA andManfredi), Virginia 5-INTA (a product of a selectionperformed in Florida, USA, and introducedinto Argentina in 1964 with the pedigree Fla.416-2) — occupy the remaining 10% of thegroundnut producing area of Cordoba. The lasttwo mentioned varieties have increased inhectarage more than the others.UtilizationProducers sell their kernels to buyers, who storethem, as well as to cooperatives or associationsin the region, who in their own time sell theproduct to industry. In the groundnut region ofCordoba, there are eight oil factories whoseprimary input material is groundnut. Threeyears ago, the oil industry absorbed about 75%of the total production.Research ProblemsThe greatest percentage of the area is plantedwith varieties of the subsp fastigiata. Problemsassociated with this type are (a) no seed dormancywith a consequent sprouting risk; (b)fragility of the pegs which causes great yieldlosses due to the easy separation of pods fromthe pegs; (c) generally a low fat content; (d) lowyield potential; and (e) high susceptibility toleaf spot attacks by Cercospora arachidicolaand C. personata.Groundnut diseases and insect pests do notyet represent a grave danger, but late attacks ofleaf spot are common. Occasionally, when theseattacks occur early (early leaf spot) in the vegetativecycle, yield is affected. In the past threeyears, isolated cases of a scab (Sphace/omaarachidis) infection have been found. It appearsto show a preference for certain varieties. InCbrdoba, rust (Puccinia arachidis) is not found.Root rot and pod rot, produced by differentorganisms, are seasonally present undermonoculture or during adverse climatic conditionsin the maturing period of the pod.Regarding insect pests, few cases exist ofdamage by subterranean insects {Diabroticaspeciosa Germ.), or by the small red spider(Tetranychus telarius) which is present especiallyduring long dry periods.With the present harvesting machines there isa loss of up to 30% of the harvested material.Also the picking and shelling operations simultaneouslyreduce quality and aggravate thedanger of aflatoxin contamination.Institutions w i t h Research ProjectsSince 1944, the Manfredi Experimental Stationin Central Cbrdoba province has been respon-242

sible for varietal and cultural improvements ofgroundnut. Other Experimental Stations whichlike Manfredi are dependent on INTA and whichare situated in different provinces, conductyield testing on different varieties provided bythe Manfredi Experimental Station.The INTA Microbiology Institute in Castelar(province of Buenos Aires) analyzes grades ofaflatoxin infection in groundnut samples fromgrowers with fields in Cordoba; they also identifyvarieties and lines of groundnut with possibleresistance to the toxin.The Botanical Institute of the Northeast inCorrentes conducts research on the physiology,cytogenetics and cytotaxonomy of thegenus Arachis.Manfredi Experiment StationResearch ProjectsThe station is responsible for the developmentof new cultivars by selection, intervarietal andinterspecific crossing. A collection of about1500 accessions of Arachis hypogaea is maintained.Between 1977-80, another 180 sampleswere accumulated in the NW of Argentina,Bolivia, Paraguay, Brazil and Peru. All this materialis sown each two or three years. There isalso a living collection of a wild species ofArachis and of interspecific hybrids between Ahypogaea and A batizocoi.A. cardenasii and Aspegazzini. These last named hybrids wereobtained at the North Carolina State University,USA and have been used in interspecific crosseswith varieties belonging to the subspeciesfastigiata.The station also investigates the improvementof production methodology especiallysowing density, row spacing, digging and pickingmachinery, natural drying, rotations andirrigation.Research is conducted on diseases that attackthe overhead and subterranean parts of thegroundnut. These studies include chemical controlmeasures and the evaluation of diseaseresistance in lines and varieties. Work is alsoconducted on soil deficiencies and herbicideevaluations.Further Research NeedsOne of the earlier goals was the attainment of ahigh oil content in new varieties. Now, researchis being directed to finding varieties with akernel of high quality and adequate size fordirect consumption, and to meet the demandsof the international market.243

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in BrazilA. S. Pompeu*ProductionAlthough peanuts are an important source ofprotein and oil, Brazilian production has beendecreasing since 1972. Between 1972 and 1978,the cultivated area declined by 66.8% and productionfell by 66% (Table 1). Production decreaseddue to a reduction in the cultivatedarea, mainly in the State of Sao Paulo, theleading peanut producer. Changes in stategovernment priorities and a shifting interestamong farmers toward more profitable crops,e.g., soybeans, were responsible for this decline.Sao Paulo State was responsible for 70% ofthetotal production in 1978. Two other principalpeanut producing states were Parana and MatoGrosso do Sul, which accounted for 15.5% and7.7% of the Brazilian production, respectively(Table 2).Peanuts are cultivated twice a year in thestates of Sao Paulo, Parana and Mato Grossodo Sul, — in the rainy season with sowingstarting at the end of August, and in the dryseason beginning late January or early February.During 1978, 74.2% of production camefrom the rainy season crop.Although the average Brazilian production in1978 of 1290 kg/ha may be considered low whencompared with 2958 kg/ha in the 1978 USA crop,this is not entirely true if the cultivation systemadopted in Brazil is considered. Peanuts areplanted in small rented areas ranging from5 to 30 ha using a low level of farm technology.The northwest of Sao Paulo State is thetraditional region of peanut production. However,recently peanut cultivation has expanded* Genetics Department, Instituto Agronomico, P.O.Box 28,13 100 Campinas, S.P., Brazil.Table 1. Brazilian peanut production, harvestedarea, and yield, 1972—78.Production Harvested area YieldYear (t) (ha) (kg/ha)1972 956 200 758 600 12601973 589 887 506 083 11661974 452 722 373 637 12111975 441987 345 095 12801976 509 905 371465 13721977 320 721 228 747 14021978 325 197 252 000 1290Source: Institute Braslleiro de Geografia e Estetistica (1975,1976, 1978), Institute de Economla Agrfcola (1972),Food & Agriculture Organization (1978).toward the northeast region of this state infields ranging from 300 to 500 ha cultivated duringthe rainy season by growers who are able toapply a better level of technology. The productivityof these new fields has varied from2200 to 2500 kg/ha.UtilizationDistribution and utilization details of the 1979crop, estimated to be 450 000 metric tons (t) arepresented in Figure 1. It was calculated that 10%of the total production was retained by growersfor new plantings, 74% went to industries for oilextraction, 11 % was consumed (roasted, salted,candies), and the remaining 5% was exportedwith and without shell. The refined peanut oil isused in human nutrition. A by-product in the oilrefining process is used for making soap. Thepeanut cake — residue from oil processing— is used for livestock feeding.244

Source: CACEX (1980).Figure 1. Brazilian peanut production flowchart, 1979.Research ProblemsAlthough peanuts are produced in at leastthe following 11 states of Brazil — Sao Paulo,Parana, Mato Grosso do Sul, Rio Grande do Sul,Minas Gerais, Bahia, Goias, Ceara, Sergipe,Paraiba and Santa Catarina — research on thiscrop has been conducted only in the stateof Sao Paulo. In order to increase yield, itis necessary to establish multidisciplinaryteams consisting of at least a breeder,phytopathologist, agronomist, and an en-245

tomologist, at state levels. These teams woulddetermine the limiting factors for peanut productionand propose solutions.In general, the following topics should betaken into account for a research program inBrazil — introduction and evaluation ofgermplasm in the producing states; identificationof the factors affecting yield, e.g., diseases,insects, and their importance; effects of liming,irrigation, fertilization and organic matter onyields; control of the aflatoxin producing fungusAspergillus flavus; determination of thebest sowing time within seasons, and bestpopulation densities; production systems andcrop rotation; and breeding for disease andinsect resistance. The Cercospora leaf spotscaused by C. arachidicola and Cercosporidiumpersonatum are the important diseases. Amongthe insects, the thrips, Enneothrips flavens, is aserious pest in reducing peanut yield in S. PauloState.Further Research NeedsOther peanut research needs should take intoaccount the interaction of peanut x Rhizobium,integrated control for peanut pests, breedingfor resistance XoAspergillus flavus, breeding forearliness, breeding for changing peanut oilcomposition, and monitoring potentially importantdiseases such as rust.246

Peanut Production, Utilization, ResearchProblems and Further Research in VenezuelaBruno Mazzani*ProductionPeanuts were probably grown in Venezuelabefore the Spanish colonization occurred.Arawak Indians were responsible for spreadingpeanuts from its southern center of origin to theCaribbean region. Until recently peanuts havebeen commonly produced on a family scale bysmall farmers all over the country. Modernmechanized production on a large scale commencedonly 20 years ago, following successfulexperiments on peanut adaptation to the ecologyof the eastern Llanos region of Venezuela.This region which is characterized by sandysoils of low fertility, has a rainy season of about1000 mm which is unevenly distributed fromMay to November. This is followed by a dry season(November-May) with practically no rainat all. The region includes more than a millionhectares. The altitude ranges from 70 to 300 mabove sea level and the topography is flat orsmoothly undulating.The yield of rainfed peanuts is highly variable,ranging from 700 to 1800 kg/ha (Table 1). Productionarea figures for the states, expressed as apercentage of the total, are Anzoategui 85.1;Monagas 10.1; Falcon 1.4; Miranda 0.2 andothers 3.2. Eastern Llanos, where Anzoateguiand Monagas states are located, account for95.2% of the total area. Irrigated peanuts coverabout 25% of the total area. Yields of irrigatedpeanuts are over 4 t/ha and are less variablethan yields of rainfed peanuts. The latter aregrown on fields 10-500 ha in size while irrigatedpeanuts are produced on fields rangingfrom 50 to 300 ha.The main cultivars grown are Florunner (irrigated)and Red Starr (rainfed). Seeds of bothcultivars are imported from the United States.* Centra Nacional de Investigaciones Agropecuarlas,HA, Maracay, Venezuela.Table 1. Peanut production in Venezuela.Production Area YieldYear (metric tons) (hectares) (kg/ha)1962 1805 1 924 9381966 2 254 2 300 9801970 7 077 9 700 7291974 27 781 30 701 9081978 25 833 18 000 14351979 27 000 (e) 14 684 (e) 1839(e) estimated.The local cultivar 15607 is also grown on a smallscale from seed produced in Venezuela. Seedrates are 60-120 kg/ha. Inoculation of seeds isnot practiced. One t/ha of lime and one t/ha offertilizer (6-12-6 or similar) are currently appliedto the soil before sowing.Weeds are controlled by herbicides, appliedas pre-emergence or incorporated into the soilbefore sowing. Weekly applications of fungicidesand insecticides afford effective controlof diseases and harmful insects. No hand laboris used. Cultural practices from land preparationto harvest combining are mechanized.Two interesting effects of the introduction ofpeanut culture to Eastern Llanos are: (Da rapidimprovement in soil fertility and texture and(2) the composition of the savannah flora israpidly changing as a number of new speciesappear on the peanut fallow. The old species aredisappearing from the fallows.UtilizationApproximately 50% of the crop is processedfor oil and residual meal production. Thebalance is used for direct consumption asroasted peanuts and other confectionery pro-247

ducts. Sometimes the haulms of peanut plantsare recovered after combining and baled as hayfor feed. Its nutritive value is highly regarded.Research ProblemsCurrent research is performed in several experimentstations directed by the Ministry of Agricultureand universities. The main problemsbeing faced include different aspects of peanutgrowing such as crop rotations, disease andpest control, chemical weeding, varietal resistanceto leaf spots and rust, soil amendmentsand fertilizers, and seed inoculation.The results of research on peanuts have beenand are being published in a number of papers.Their contents according to the most importantaspects give an idea of the research beingconducted. The subject matter and the numberof papers which have been published for thesesubjects are: soils and fertilizers, 35, breeding,23; cultural practices, 14; diseases and pests,11; experimental techniques, 6; weed control,10; Rhizobium and nodulation, 6; haymaking.4; yields, 3; harvesting, 2; mechanization, 2;phenology, 1; and analysis and composition, 2.Between 1960-1979, there have been 119papers published on peanut culture and improvement.A collection of approximately 600 cultivars ismaintained at two different locations (Maracayand El Tigre).Further Research NeedsThe improvement of yields, the easy availabilityof land, a support price sustained by the Governmentand the recent introduction of othercrops such as cotton and sorghum for rotationwith peanut, are reasons for the probable expansionof peanut growing in the easternLlanos of Venezuela. This in turn creates anurgent need for more research. The main objectivesare reducing the cost of the most expensivepractices of peanut production andresearching the most important aspects ofgenetic and agronomic improvement.248

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in MalawiP. K. Sibale and C. T. Kisyombe*Malawi is a relatively long and narrow country,which extends some 900 km from North toSouth and 200 km from East to West. It ispositioned along the Great African Rift Valley andthe altitude varies considerably from 50 to3000 m above sea level.The climate is ideal for groundnut growing inthe altitude range of 200-1500 m and onlyone crop per season is grown during theNovember-May rainy season.The problems encountered in productionwith this smallholder crop, have mainly been ofan agronomic nature but foliar and soilbornediseases also play an important role in limitingproduction.Research on groundnuts has been carried outsince the early fifties so that the farmer now haslocally tested research findings to ease most ofthe problem he encounters.This report reviews some research and productionproblems and shows those areas whereachievements have been obtained. It also pinpointsproblem areas of research which needadditional effort in the future.ProductionTable 1 shows the production during the past 10years (Ministry of Agriculture and Natural Resources).Thefigures reflect only thegroundnutpurchases by theAgricultural Development andMarketing Corporation (ADMARC). A lot moregroundnuts are sold and consumed locallywithout reaching ADMARC. Production is expectedto rise steeply as a result of directives toextend production of the crop to growers onlarge estates.* Senior Groundnut Breeder and Senior GroundnutPathologist,respectively, Chitedze Agricultural ResearchStation, P. O. Box 158, Lilongwe, Malawi.Recommended CultivarsThere are four recommended cultivars —Chalimbana, Mani Pintar, Malimba and RG1. Each is grown in a range of different areas(Fig. 1).1. Chalimbana. It is a large seeded confectionerynut recommended for the plateauareas (altitude range 1000-1500 m). Thisvariety forms the basis of the groundnutexport trade.2. Mani Pintar. This medium sized red andwhite variegated oil nut, is recommendedfor the lake shore areas (altitude range500-750 m). It originated from Bolivia, isvery adapted to most groundnut growingareas of Malawi and has a comparativelyhigher yield potential than any of therecommended varieties.3. Malimba. Itis ashortseasoncultivaroftheSpanish type and is recommended for thelow lying hot areas (altitude range 100-300 m).4. RG1. A medium sized oil/confectionery nutwhich is the recommended variety forThyolo/Mulanje area. It is a locally bredrosette resistant variety.All the four varieties are susceptible to themajor groundnut diseases which limit production,except RG1 variety which is resistant tothegroundnut rosette virus.UtilizationThe main uses of groundnuts are confectionery(of which a large part is exported); oil expressionwith the residual cake being used as cattlefeed; local consumption in various forms(boiled, roasted etc); and groundnut hay is fedto animals.249

Table 1. Groundnut purchases by ADM ARC (in short tons, 2000 lbs).Year Southern region Central region Northern region Total1969 3 352 35 045 2 458 40 8551970 3 741 24 219 1 139 29 0991971 9 500 31000 1 500 42 0001972 11063 29 588 2 272 42 9231973 8 228 21828 2 899 32 9551974 2638 26 863 2 225 317261975 1 967 32 895 1303 36 1651976 1 121 33 248 1 554 35 9231977 456 18 499 1394 20 3491978 516 10 439 1313 12 2681979 1000 21500 1800 24 300 aa. Estimated.Research and ResearchProblemsThe Malawi groundnut improvement programis split into breeding, pathology and agronomysubprograms which reflect the major types ofproblems encountered in groundnut production.The relationship among the subprogramsis close and fully integrated with one coordinator.The agronomy subprogram has sorted outmost of the questions relating to fertilizer use,spacing and plant population, place ofgroundnuts in rotation, time of planting, harvestingtime, and drying procedures etc. Informationon all these aspects has been passed tofarmers.Varietal ImprovementIn Malawi it has been achieved by the standardmethods of introduction, selection, and breeding.Introduction has been an effective tool as isevidenced by three of the recommended cultivatewhich have been introduced from abroad— Chalimbana, Mani Pintar and Malimba. Thistool will continue to play an important role inthe future.Deliberate breeding is now playing a greaterrole in our improvement program. The broadobjective is to develop high yielding varietieswith resistance to the main diseases which limitproduction. The RG1 variety, for example, is aproduct of this work.Considerable effort is also expended to ensurethat the product is acceptable to the producer,processor and consumer. Acceptableseed size is an example, and experience hasshown that the producer and the local consumergenerally are not keen to change to avariety that has kernels markedly smaller thanthose of the Chalimbana variety.The following are some of the breeding programsthat have been undertaken:Breeding for Kernel Size and YieldTables 2 and 3 present some data on seed sizeand yield performance respectively for a recentlyreleased hybrid (E879/6/4) derived from across between Chalimbana and an Americanvariety. This new variety has kernels larger thanthose of Chalimbana and a similar yield potential.Breeding for Disease ResistanceBreeding for rosette resistance has been undertakenin the past and the RG1 variety is a rosetteresistant product from this program. Kernel sizeimprovement of rosette resistant hybrids hasalso been undertaken and several such lines arenow in advanced yield trials.Breeding for rust resistance has also beenconducted utilizing Tarapoto and the FESR lines250

as sources of resistance. From our experience,Tarapoto has not been such a useful source ofresistance. Better sources have been acquiredfrom the ICRISAT program and these will befurther utilized in our breeding programs.Breeding for Cercospora resistance has notbeen undertaken because of the lack of sourcesof resistance from the cultivated tetraploidArachis sp. We hope to take advantage of anyuseful material coming out of ICRISAT'sinterspecific work.We have already acquired some lines reputedto carry resistance to aflatoxin, but no work hasso far been undertaken mostly due to lack ofpersonnel.The Diallel Selective Mating ProgramThis is a breeding procedure proposed byJensen to supplement conventional breedingsystems for autogamous crops.Our program was initiated in 1975 using sixselected parents. Wearenowcarrying differentcomposite hybrid populations in various folialgenerations. A lot of useful variability has beengenerated using this procedure and there areseveral lines showing a lot of promise.P r o t e c t i o n f r o m Weeds,Diseases a n d PestsGroundnut protection in Malawi involves thecontrol of weeds, disease and pests in that orderof decreasing importance.Weed ProblemsSeveral types of grasses are a problem early inthe groundnut growing season—from Decemberto about February. Broadleaved weedsof various types become dominant ingroundnuts later in the season from aboutFebruary to harvest time, which is usually inTable 2. Seed size of Chalimbana hybrids,1978—79 Mason (mean weighting of100 SMK dried to 7.5% moisture content).Seed size (g)Treated withDace-nil 2787Not treatedwith DaconllFigure 1. Major areas of groundnut productionin Malawi.Chalimbana 135.4 126.7E8885/1/4A 123.9 117.0E879/6/4 148.7 132.9E879/9/2 123.1 116.7E879/1/2 123.4 112.6E889/6/4 147.1 126.4251

Table 3.Results of yield trials for the 1 9 7 7 - 7 8 to 1 9 7 9 - 8 0 seasons, Chitedze (kg/ha).1977-78 1978-79 1979-80a b c a b c a b cChalimbana (+) 4141 2950 71 4192 2844 68 3096 2100 68E885/1/4A (+) 5089 3588 71 2822 2074 75 2089 1496 72E879/1/2 (+) 4526 3134 69 3948 2652 67 2918 1987 67E879/6/4 (+) 4941 3459 70 4829 3303 69 2837 1989 71Chalimbana (-) 4252 2918 69 3407 2474 73 2170 1507 69E885/1/4A(-) 4326 3064 71 2792 1866 67 1970 1437 73E879/1/1 (-) 4200 2884 69 3555 2578 73 2185 1507 69E879/6/4 (-) 4785 3321 69 3577 2544 71 2007 1441 73S.E. ±207.6 ±161.1 ±1.7 ±310.6 ±232.0 ±1.1 ±153.1 ±120.1 ±1.5CV 8% 9% 4% 15% 16% 3% 11% 13% 4%a= Unahelled yield (kg/ha); b - Shelled yield (kg/ha); c - Shelling %;(+) - Treated with Daconll; (-) - Not treated.May and June. Alectra sp is the only well-knownand widespread parasitic w e e d of groundnut inMalawi.Handweeding with a traditional hoe is themost effective method of weed control. However,it is a labor demanding and t i m e consumingmethod.Chemical weed control w i t h Lasso has beenfound successful against grasses w h e n theherbicide is applied to the soil after the firstrains.Handpulling is an effective control m e t h o d forthe broadleaved weeds and Alectra sp. Thism e t h o d is also labor d e m a n d i n g and t i m econsuming.Crop rotation has been noted in Malawi to beanother g o o d weed control method but it seemsto be less effective in many cases.W h e n early weeding and banking cultivationof the g r o u n d n u t crop have been done atpegging t i m e , most subsequent weeds aresmothered by t h e vigorous g r o w t h of t h egroundnut crop.D i s e a s e P r o b l e m sThe virus diseases are rosette and peanut m o t -tle virus (PMV). Important foliar fungaldiseases w h i c h occur in the m e d i u m altitudeareas (1000-1500 m elevation) w h e r e it is cool,are as f o l l o w s in order of decreasing importance:pepper spot and leaf scorch, Leptosphaerulinatrifolii (Rost) Petr.; early leaf spot,Cercospora arachidicola Hori.; groundnut rust,Puccinia arachidis Speg.; web blotch, Phomaarachidicola Marasas, Pauer and Boerema; andlate leaf spot, Cercosporidium personatum Berkand Curt. Foliar fungal diseases which occur inthe low altitude areas (from 200-1000 m elevationabove sea level) where it is hot and humid,in order of decreasing importance are: P.arachidis Speg., C. personatum Berk and Curt,C. arachidicola Hori and L trifolii (Rost) Petr.Fusarium wilt caused by Fusarium oxysporumis a serious soilborne fungal disease ofgroundnuts in Malawi. It also causes p o d rotsusually when groundnuts are harvested late.The six possible disease control m e t h o d sare: varietal control, e.g., R G 1 ; early planting;rotation and crop burial; removal of volunteerplants; g o o d crop husbandry; and fungicidalcontrol of foliar fungal diseases.Pest P r o b l e m sLarvae (caterpillars) of leaf-eating insects arec o m m o n l y f o u n d .The aphid,Aphis craccivora Koch i s t h e v e c t o rresponsible for transmitting the g r o u n d n u trosette virus.The g r o u n d n u t jassid {Empoasca facialis) is252

associated with the incidence of the fungaldisease caused by Leptosphaerulina trifolii(Rost) Petr. (Mercer 1977).White grubs (Eulepida mashona) are larvae ofa beetle. These grubs are soilborne pests whichcause a wilt of groundnuts by damaging theroots.Cutworms (Agrotis spp) are sometimes aproblem, particularly at the seedling stage. Tocontrol pests in general it would not appearpossible to recommend routine spraying ofinsecticides in conjunction with fungicides. Ifserious infestations did occur, the occasionalspray would be worthwhile (Mercer 1975).Pirimiphos — methyl or carbaryl are used tocontrol leaf-eaters on groundnuts when theyassume destructive proportions. Dimethoate isused to control aphids in order to reduce theirnumbers.Future Research NeedsThe major groundnut buyers have indicated agrowing demand for the large confectionerynuts and Malawi has to aim at satisfying part ofthis demand. The best strategy for Malawiwould be to ensure that yields per unit area ofChalimbana types are maintained, if not improved.Research work has shown that Chalimbanahas a fairly high yield potential if given goodmanagement. However, it is felt that workshould be carried out to raise this yield levelfrom a genetic point of view. Recent researchwork to determine the physiological aspectslimiting yield in Malawi groundnut cultivars hasgiven us some insight into the probable limitingfactors.ReferencesJENSEN, N. F. 1970. A diallel selective mating systemfor cereal breeding. Crop Science 10: 629-635.MERCER, P. C. 1975. Knapsack spraying of fungicidesto Cercospora (Mycosphaerella) leafspots ofgroundnuts in Malawi. Agricultural Research Councilof Malawi. Occasional Report No. 4.M ERCER, P. C. 1977. Pests and diseases of groundnutsin Malawi. Pages 483-488 in 1. Virus and foliardiseases. Oleagineux 32.MINISTRY OF AGRICULTURE AND NATURALRESOURCES — Guide to agricultural production inMalawi 1979-80.253

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in MaliD. Soumano*Groundnuts play an important part in Malianagriculture as one of the principal cash crops. Inthe early 1960's groundnuts accounted for 38%of the total value of Malian exports. The share ofgroundnuts in the domestic food economy issizable.ProductionA large portion of our arable land is suited togroundnut agriculture, principally in the areaswithin the 500-1400 mm rainfall limits. Withinthat zone, groundnut production varies accordingto climate and soil conditions as well ascurrent farming practices.The principal groundnut production centersin Mali are Kayes, Kenieba, Bafoulabe, Kita,Kolo Kani, Banamba, Koulikoro, Segou, Manicepe,San, and Tominian. All of those centersare serviced by an extension agency thatspecializes in groundnut agriculture — theGroundnut and Food Crop Extension Service("L'Operation Arachide et CulturesVivieres" — OACV). Outside of the territory,groundnuts are considered a minor crop.Groundnut production has fluctuated considerablyover the past 10 years (1969-1979). It fellduring the period 1960-1967 with exportsplunging from 38 to 16% of the total Malianexportation. The reasons for the productiondrop were twofold; climatic quirks and outmodedproduction methods.Malian agriculture in general is farf rom beingfreed from the effects of our uncertain climate.All field crop production was considerably setback in Mali during the drought years of 1969-1974. Plantings were futile due to insufficient ortotally lacking rainfall. Irregular rainfall oftenforces the farmer to replant (if he has leftoverseed stocks) and the plant stands, representing* Engineer of Agronomic Research, B.P. 258,Bamako, Mali.several replantings, neither develop nor completematurity in a normal fashion. The yields insuch cases are significantly inferior comparedto normal yield levels.Proven agronomic practices are seldom ifever adopted in most of our agricultural regions.Farming is carried out according to traditionalpractices in which productivity is verypoor. Extension services, however, have existedfor several years with the aim of extendingimproved farming techniques which can increasecrop yields. Those improved techniquesthat have been defined by agronomic researchinclude animal traction farming, optimalplanting dates and plant densities, seedtreatment with fungicides and insecticides, useof chemical fertilizers, use of herbicides, theuse of crop rotations which include cash crops,and the careful storage of groundnut harvests.However, implementation of these agronomicpractices has been met with seriousdifficulties in rural areas. It is forthat reason thatour production has little benefited from thosemethods.Malian groundnut area, production, and yieldin the OACV territory during the past severalyears are shown in Table 1.UtilizationGroundnuts are important in the Malian diet.That fact is reflected by the annual per capitagroundnut consumption of 15 kg. They areeaten in a variety of ways: fresh, dried andgrilled, salted, boiled, ground and served withsugar or honey, ground into paste, and used asa sauce base. The last mentioned use is themost common.Groundnut hulls are ground and used asfuel in two Malian groundnut refineries; SEPONand SEPAMA. At the village level, groundnuthulls are burned and the ashes are used in localsoap and lye production.254

Table 1. Groundnut area, production, andyield.Area Production YieldYear (ha) (tonnes) (kg/ha)1967 46 240 23 600 5101968 48 650 27 855 5721969 71 630 56 655 7901970 102 600 68 507 6671971 92 355 75 185 8151972 96 000 67 076 6981973 89 660 68319 7611974 107 300 110 300 10201975 170 455 150 000 11301976 164 380 160 440 9761977 152 100 102 400 6731978 120 120 100 910 8401979 112 250 85 000 757Groundnut plants provide an important forageduring the dry season when fresh pasturegrazing is no longer available. With the growinguse of animal traction the use of groundnuts forforage is gaining importance — an example ofthe association of crop and animal agriculture.In the intensive cultivation areas, groundnutsprovide a substantial source of income for thefarmers. The commercial market is partly exported(by SOMIEX) and partly processed bythe two Malian processors SEPOM and SEPAMA.Groundnut processing provides culinary oil,and meal. Groundnut meal is used in animalfeed mixtures at the National Large AnimalResearch Center (CNRZ and the Poultry Centerat Sotuba (CAS).The population of Mali exceeds 6 million andis growing steadily. It is evident that the domesticneeds of groundnuts and groundnut byproductsare far from being met. It is for thatreason that we look for ways through researchto increase groundnut production. Table 2shows production and end uses of Maliangroundnuts.Research Problems andFuture Research DirectionsWe cannot expect to find clear-cut solutions toproblems affecting an increase in groundnut255

production. We must define the parameters andlet the solutions evolve over time.We have outlined the following areas ofresearch concentration in groundnuts:1. Cultivars. There should be an ongoingsearch for cultivars adapted to particularrainfall zones and soil types. The principalselection criteria should be yield, floweringcycle in harmony with rainfall cycle,plants adapted to mechanization, diseaseresistance, and food technology considerationslike grain size, oil content, etc.2. Agronomic techniques. We must identifyoptimal planting dates; soil preparationmethods, plant densities, timingof fertilizer applications, and storagetechniques.3. Chemical fertilizers. We must determineoptimal economic returns under intensivecultivation situations.4. Pesticides. We must find optimal dosagesand formulations of fungicides and insecticides.5. Chemical herbicides. We must find themost economically feasible and agronomicallyeffective formulations.6. General agronomy. We must accelerateresearch of rhizobial inoculations andgrowth regulation.7. The use of groundnut hay for feed totraction animals.8. Quality control of groundnut —particularly aflatoxin detection and control.Additionally we must consider the liaisonbetween our research and the extension of ourresearch. The following play a part in thatbridge: the maintenance of foundation seedstocks of released varieties, the quality controlof seed increase fields, the measure of qualitycontrol for marketing industrial groundnuts, thedefinition of quality standards for confectionerygroundnuts, and quality sampling of exportedgrain lots.The above mentioned research themes havealready been outlined in our 5 year MalianResearch Plan. Already our research structureshave addressed themselves to these questionsfor several years with the following concreteresults:1. The release of five commercial varietieswhich are already at the farmer level —28-206, 47-10, 59-127, 55-437, GH-119-20.2. Optimal soil preparation techniques whichconsist of plowing in zones above 900 mmrainfall and harrowing operations in areaslower than 900 mm rainfall.3. The early planting of late maturing varietieswith plant spacings of 0.6 x 0.15 mfor late varieties and 0.4 x 0.15 m for earlyvarieties.4. Recommended seed treatment is a mixtureof 25% thiram, 25% heptachlor and25% autraquinone.5. Chemical fertilizer is recommended at 65kg/ha superphosphate (21% P2O5). Thisdose is considered economically efficient.Higher doses are now being consideredfor groundnut-cereal rotations.6. Different herbicides are now being considered.The most promising herbicide isgerathene (CIBA Geigy) which is alreadybeing used at the farmer level.These research results have been promisingand over time they will be defined to fit changingsituations.This summary reports the state of the art ofapplied groundnut research in Mali and whichwe find necessary in order to intensifygroundnut production. Still and all, we need tofurther mobilize human and financial resourcesto achieve our goal.256

Groundnut Production, Utilization, ResearchProblems and Further Research Needsin MozambiqueA. D. Malithano*ProductionMozambique has a surface area of 79.9 millionhectares of which only 18.8% is used for agriculture.Unoccupied land which can be used foragriculture occupies about 52.9 million ha.In 1969, 155 000 ha of groundnut were estimatedto be planted representing 3.5% of thetotal area under cultivation and makinggroundnuts the fifth crop in importance in termsof area (Missao de Inquerito Agricola-MIA1969).The production suitability of the groundnutareas depends on the rainfall and soil type(Almeida 1968). In the areas that are relativelydry and have an erratic and shortduration rainfall, e.g., the southern region with600-800 mm/yr, early maturing varieties ofgroundnuts are recommended. In the centraland northern regions with 800-1200 mm/yr,late maturing varieties are grown. Areas withheavy clay, black, gray and compact soils werenot considered for groundnut production.Most of the groundnuts are produced in thecoastal area, especially in the provinces ofNampula, Inhambane, Zambezia, Maputo andGaza.Table 1 summarizes the number of farmers,hectarage and yield in specified years. In 1970,farmer numbers doubled and hectarage increased,butyield was very low. Since then yieldhas continued to decrease and today there is acritical groundnut shortage.Y i e l dThe average is very low and ranges from 266 to521 kg/ha. The main causes are unimproved* Advisor, Groundnut Improvement Project, UniversityEduardo Mondlane, Maputo, Mozambique.varieties, traditional production methods, noruse of fertilizers, and diseases. About 99% ofthe groundnut area is cultivated by the localpopulation on traditional farm units averagingabout 0.34 ha.VarietiesRecommendations for the northern region wereSpanish, 48/21, Namarroi and Fumo; for thecentral region Paulista, White Spanish andBombay; and for the southern region NatalCommon and Valencia, according to Almeida(1968), Sousa (1971) and Milheiro and Rodrigues(1973), respectively. Southern region recommendationsbased on data obtained fromUmbeluzi Agricultural Experimental Stationmay be invalid as the station soils are notrepresentative of the groundnut growing areas.The above recommendations were not accompaniedby an effective seed multiplicationand distribution program. The small farmersplanted their own seed resulting in mixtures ofearly and late maturing types which causeddifficulties at harvest and depressed yield.C r o p H u s b a n d r yImproved varieties alone will not make anappreciable increase in yield. If culturalmethods were improved, yields could be increasedconsiderably. Therefore, much effortshould be made by extension services to improvecrop husbandry, but because these servicesare inadequate and inefficient the problemstill continues.Mixed cropping is practiced and groundnutsare nearly always intercropped with maize,cassava, sorghum, millet and plantation cropssuch as coconut palm and cashew (Malithano1979, unpublished; Malithano and van Leeuwen1980). When interplanted, groundnut density is257

Table 1.Year1961-67196819691970very low. It is also low when groundnut is grownas a pure crop (Malithano 1979, unpublished).Thus mixed cropping and low planting densityas practiced by farmers in Mozambique adverselyaffect groundnut yield.Soil preparation varies from zero tillage toadequate seedbed preparation. The hoe isthe main tool for all types of cultivation. Veryfew farmers use ox-drawn plows. Manygroundnut farm units are very small becausethe farmer cannot prepare a large piece of landbefore the rains by using a hoe only. Therefore,inadequate land preparation, inefficient farmtools and small farm units minimize the quantityof groundnuts that can be produced.Late planting, e.g., after the planting rains, iscommon because the land is not ready for sowingat the beginning of the rains. Milheiro(1962)in northern Mozambique has shown that lateplanting reduces yield because the number ofplants attacked by groundnut rosette virus increaseswith the delay in planting. When plantingwas delayed until January, nearly all theplants were attacked by rosette and the yieldwas very low.D i s e a s e sImportant diseases such as rosette and leaf spotcaused by Cercospora arachidicola Hori andCercosporidium personatum (Berk. & Curt.)Deighton are endemic to Mozambique andcause great yield losses. Another importantdisease is rust caused by Puccinia arachidisSpeg. Many other minor diseases also occur.F e r t i l i z e r sGroundnut termors, areaproduction, 1 9 6 1 - 1 9 7 0 .No. of farmers46\1431434 466413 583936 338Area sown(ha)155 372126 159230 722253 817• o w n , andProduction(tonnes)64 7775681680 89455 186Source: Missao de Inquerto Agrlcola de Mocambique 1968,1969, and 1970.They have not been used by small farmers.Experiments carried out at Mocuba and Umbeluziin northern and southern Mozambique,respectively, did not support their use (Almeida1968). Most groundnut production soils insouthern Mozambique are sandy and very poorin mineral nutrients. Correct use of fertilizerswill boost yield.N a t u r a l H a z a r d sIn 1976 and 1977 a large part of the crop in thesouth was destroyed by the off-season rainswhich came at harvesting time. Also from1975-1980, rains have been erratic and unpredictablecausing planting delays. Prolongeddroughts over the past two seasons have completelydamaged the crop in the south.In many southern areas the consecutive cropfailures have caused groundnuts to completelydisappear from the local market in the last fouryears. Many farmers do not have the seedandthisalonewill greatly reduce the area undergroundnuts in 1980, with a consequent reductionin total yield.The Government is very much concernedwith this drastic reduction in production becauseof its effect on the economy and its farreachingsocial consequences, especially in thesouthern region where, as a food crop, itsscarcity is keenly feltS e e d I m p o r t a t i o nTwo varieties, Starr and Tamnut 74 of shortvegetative cycle and early maturity were importedby the Government in large quantities in1977 from USA for multiplication and distributionto farmers in the southern region. In 1979,variety Manipintar was imported from Malawiand the varieties Makulu Red, Mwitundeand Malimba were supplied by the InstituteNacional de Ivestigacao Agronomico (INIA).Seed MultiplicationIt is carried out by the National Seed Company(NSC), administered by the Ministry of Agriculture.The Company is a joint venture between theGovernment of Mozambique and Nordic countries.Its staff are recruited by FAO and theSwedish International Development Authority(SIDA). The multiplication of Starr and Tamnut74 started in 1978 and that of Manipintar, Makulu258

Red, Mwitunde, and Malimba in 1979. Statefarms are the main centers of multiplication.Some cooperatives, agricultural research stationsand training centers are also involved.UtilizationMost of the produce is consumed as food andonly a small percentage is industrialized. Forhuman consumption, groundnuts may becrushed for oil, and to flavor vegetables, meatand fish, or be eaten directly. Woodroff (1973)gives a detailed account of the uses ofgroundnuts.G r o u n d n u t O i lLocal consumption of groundnut oil as cookingoil is very high. The oil is used in cooking meat,fish, vegetables and rice. Small quantities arealso used in seasoning salad.F o o d F l a v o r i n gGroundnut flour is added to meat, fish, vegetables,cassava and sweet potatoes after theyhave been cooked sufficiently. The food isserved after it has simmered for some time toallow the groundnut flour to cook.Groundnut milk is used in chicken, meat andfish curries. The milk is obtained by putting finegroundnut flour in a sieve and mixing with water.The extract is then added to the food.Groudnut curry sauce is a favorite dish whichis prepared by using very fine groundnut powderin a water suspension. It is added to friedtomatoes and onion, allowed to simmer andthen served with rice.D i r e c t C o n s u m p t i o nFresh boiled groundnuts are widely consumed.They are cooked in the shell and served. Topreserve them, the cooked groundnuts aredried in the shell, stored and served as required.Groundnuts may also be consumed fresh orafter drying, but quantities eaten in this way areusually small as they are not very appetizing.On large farms, laborers were served boiledgroundnuts with upsa, a thick maize flour porridge.Small quantities of groundnuts are consumedroasted either in the shell or as a kernel.Research ProblemsThe Institute Nacional de InvestigacaoAgronomico (INIA), of the Ministry of Agricultureis responsible for and coordinates all agriculturalresearch in Mozambique. Other organizations,outside the Ministry of Agriculture,which are involved in research collaborate withINIA that provides infrastructures such asresearch stations, farm machinery, transport,fertilizers, insecticides, etc. It is within thisframework that the Faculty of Agriculture, UniversityEduardo Mondlane in Maputo is conductingresearch on groundnuts. Maputo islocated in a very suitable area for groundnutwork.Groundnut is one of the crops that wasneglected during the colonial era when verylittle research was conducted on this crop. Theresult has been that cultural practices haveremained unimproved and very little informationis available on varieties adapted to differentecological zones of the country. Adapted, purevarieties for use by farmers do not exist.Under thesecircumstances it is reasonable tosuggest that in Mozambique research muststart afresh and should encompass all aspectsof production such as variety trials, plantdensity, date of planting, cultural practices, cropprotection, fertilizer requirements and soiltypes. Acquisition of local and exoticgermplasm together with breeding should bean integral part of the research.ObjectivesThe objectives of research are the identificationof high-yielding varieties adapted to differentecological zones of the country for use by commercialand small farmers, and the improvementof cultural methods. These objectives cannot berealized immediately asthere are many interactingfactors requiring both short and long-termsolutions.S h o r t - t e r m O b j e c t i v e sThe most urgent and immediate need is toprovide the farmer with seed of groundnuts.This may be achieved by importation of259

groundnuts with specific agronomic characteristicsfrom those parts of the world that haveclimatic conditions similar to Mozambique. AlreadyStarr, Tamnut 74, Manipintar, MalimbaMwitunde and Makulu Red have been imported.The Faculty of Agriculture, UniversityEduardo Mondlane, has maintained and multipliedsome cultivars previously grown inMozambique and has acquired other exotic varietiesfrom different parts of the world. Most ofthese cultivars are being evaluated for yield anddisease resistance. Those varieties that performwell over years and across sites will be multipliedand distributed to farmers.Some cultivars in the Faculty collection carrytraits such as resistance to rust, rosette anddrought.Surveys have been conducted to study theexisting cultural practices used by the smallfarmers (Malithano 1979, unpublished). Thisinformation is useful in order to plan a realisticgroundnut improvement program includingintercropping.Long-term ObjectivesA major objective is the breeding of highyieldingvarieties resistant to diseases andpests, and adapted to the local conditions ofcrop production. As industrial processing ofgroundnuts for oil and animal feeding willbecome increasingly important, there is need tobreed and select varieties with a high oil andprotein content.In order to achieve these objectives it isnecessary to assemble a large germplasmmade up of both local and exotic material.Some of those collections that have specifictraits can be used for hybridization in order toincorporate desirable genes in some cultivarswith proven performance.Cultivars and breeding lines have been receivedfrom ICRISAT, FAO, USA, and severalAfrican countries. A local germplasm expeditiontook place in Southern Mozambique earlyin 1980 and another one has been planned for1981 in collaboration with the InternationalBoard for Plant Genetic Resources (IBPGR) tocollect groundnuts from the central and northernregions of Mozambique.Other aspects of research to be studied thataffect yield are cropping systems, cultural practices,fertilizer trials, plant density and date ofplanting.As Mozambique is endowed with water resources,irrigation of groundnuts will becomeimportant and research in this direction shouldbe initiated. Irrigation is particularly importantbecause dryland farming of groundnuts is subjectto great variation in yields making it difficultto predict production. In Zimbabwe, irrigationof groundnuts is becoming increasingly popularbecause of the high yield obtained by farmers(Hutchinson 1980).In order to remove the drudgery of using ahoe as a tool for all farm operations, a seriousstudy on the mechanization of production todevelop simple tools for small farmers is merited.Animal-drawn plows, seed planters andharvesters will facilitate the work of the farmerand will enable him to expand the area underproduction.Research is required to identify cultivars thatnodulate readily in virgin soils as well as in soilswhere groundnuts are currently grown. As fertilizerprices continue to rise, nitrogen fixationstudies will become increasingly important.Future Research NeedsThere are many problems associated withgroundnut research such as lack of trainedmanpower, research stations not suited togroundnut work, quarantine of exotic accessions,and storage facilities, to mention only afew.Lack of trained personnel is serious. In orderto have an interdisciplinary approach, an agronomistand a plant pathologist are requiredimmediately. Currently, an agronomist is beingrecruited.Field assistants and technicians are lacking.ICRISAT has been contacted to train one fieldassistant and two technicians.There is a need to identify locations suitablefor groundnut work. The choice of Umbeluziand Ricatia research stations, for instance, wasbased on needs to conduct research on cropsother than groundnuts.As the importation of exotic germplasm increasesso will the dangers of introducing newdiseases become more serious. Thus, stafftrained in quarantine will be of great value toour future work.260

The new introductions will need to beevaluated, documented and stored. At the momentthere are no proper storage facilities foreither short or long-term storage. There aresome funds to buy a cold r o o m for storingbreeding stocks, but the equipment has not yetbeen purchased.ReferencesALMEIDA, F. SOUSA, 1968. A cultura do amendoim emMocambique Louren co Marques. Instituto deInvestigacfioAgronomico de Mocambique. ComunicacoesNo. 15.HUTCHINSON G. 1980. Groundnut increase. The Farmer50(48): 39.MALITHANO, A. D., and VAN LEEUWEN, J. 1980.Groundnut-maize interplanting in southernMozambique. International Second Symposium onIntercropping for the Semi-Arid Areas, Morogoro,Tanzania, 4-7 Aug 1980.MILHEIRO.A. D. 1962. A cultura do amendoim; ensaiosde variedades e datas de sementeira. Gazeta doAgricultor XIV(153): 37-41.MILHEIRO, A. D., and RODRIGUES, A. F. 1973. Valorcomparativo de algumas variedades de amendoim.Agronomico Mocambicano 7(1): 1-64.MlSSAO DE INQUERITO AGRICOLA DE MOCAMBIQUE.Estatlsticas Agricolas de Mozambique 1969 and1970.Sous A, C. V. 1971. Algumas caracteristicas de cultivaresde amendoim experimentados em Mozambique.Agronomico Mogambicano LourengoMarques 5(2): 117-123.WOODROFF, J. G. 1973. Peanuts: production, processing,products. 2nd ed. Westport, Connecticut, USA:Avi Publishing.261

Groundnut Production, Research and ResearchProblems in NigerA. Mounkaila*ProductionBefore the 1973 drought, groundnut rankedthird in production after millet among the fivemajor crops of Niger (Table 1). Cultivation ofgroundnut in the pre-1973 years had beenencouraged by the presence of a marketingcorporation (SONARA), three shelling millswith a capacity of 82 000 tonnes, and three oilrefineries for exporting crude oil with a totalprocessing capacity of 105 000 t of shelledgroundnuts. This resulted in the area plantedincreasing from 325 000 to 383 000 ha between1960-68 and 1969-73.The 1973 drought and the rosette epidemic in1975 led to a dramatic decrease in the cultivatedarea and production (Table 1), with a subsequentfailure of the marketing corporation,and the shelling mills and refineries. While thepercentage of groundnut in Niger's exports was45% in 1972, it declined to 24% in 1973, and fellto 5% in 1975.In 1977 the shelling mills at Dosso andTchadoua operated at 8.5% and 3.2% of theirtotal capacity, respectively, and the OilRefineries Society of Niger of Matamey andSiconiger could only use 19% and 9.5% of theprocessing capacity. The national productionprovided only 7.4% of the crushing potential ofNiger.To rectify this deteriorating situation, Nigeradopted a policy to improve production via twoincentives: technical (improved land use, fertilizers,and use of selected seeds) and financial(establishment of finance corporations and increasedprices to farmers).The following production targets (shelledgroundnuts) were established: 1979 (80 0001);1980 (88-0001); 1981 (96 0001), 1982 (106 0001)and 1983 (120 0001). To date, these targets arebeing achieved.* Section Arscnide, CNRATarna, BP 240, Maradi,Niger.Groundnut Research in NigerUntil 1974, research was focused on comparativetrials of introduced and promoted varieties,and of cropping techniques.Since 1975, the National Institute of AgriculturalResearch of Niger (INRAN) has addedother research programs which include foundationseed production, groundnut breeding andimprovement through hybridization, and cultivationunder irrigated conditions.V a r i e t a l T r i a l s a n d I r r i g a t e dG r o u n d n u t C r o p sThe objective of this program is to identifyexotic varieties that are best suited to thecropping conditions in Niger and are superior tothe varieties already promoted in the country.This is a very old program which rose inimportance in 1976. Since then, more than 200varieties have been introduced from theneighboring countries (Senegal, Upper Volta,Nigeria, etc.) and the United States.Each year the best varieties are tested accordingto thefollowing classes: early varieties (lessthan 90 days); late varieties (more than 90days); early rosette-resistant varieties; and laterosette-resistant varieties.Fertilizer, insecticide, and fungicide trialshave accompanied these varietal tests.Since the objective is to increase groundnutproductivity in this arid country, varietal trialswere also conducted under irrigated conditions(off-season trials) in order to determine thebest varieties and the best period during theyear.for growing groundnut. In 1979 the highestyield of 5 t/ha was reached with the variety 796.F o u n d a t i o n S e e d P r o d u c t i o nThis program was started in 1975 with theobjective of providing foundation seed with a262

Table 1. Groundnut production in Nigar from 1968 to 1979 (000 tonnas).Crop 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978Millet 733 1035 871 958 919 627 883 581 1019 1130 1123Sorghum 301 388 230 267 208 126 219 254 286 334 371Cowpea 74 160 84 72 124 92 133 218 216 207 271Rice 39 39 37 27 32 46 30 29 29 27 32Groundnut 270 a 270 a 205 257 260 77 129 42 79 90 74a. Average of production in 1967, 1968, and 1969.high degree of purity. Modern facilities andequipment are used for conducting the experimentsand supplemental irrigation is given tocrops when there is deficit rainfall.Each year seeds of promoted varieties(55-437,47-16,28-206) and introduced varietiessuch as TS 3-1, are produced in sufficientquantities for supplying material to seed multiplicationcenters. Yields under these conditionscan reach 1000 kg/ha after winnowing. Theseseeds are produced in an area exceeding100 ha.G r o u n d n u t B r e e d i n ga n d I m p r o v e m e n tA crossi ng prog ram was sta rted i n 1976 with theobjective of producing varieties having thefollowing qualities: productivity, earliness,rosette resistance, rust resistance, and withdesirable agronomic and industrial characteristics.The most advanced lines were at the F7stage in June 1980.Agricultural Research ProblemsAs a consequence of the 1973 drought, Nigerhas given priority to the cultivation of cashcrops, and now groundnut ranks only fourth intotal tonnes of crop production. This policydoes not favor investment in groundnut research.Although research has made some achievements,there is an inadequacy in the transfer oftechnology from research stations to farmers'fields. It is a problem causing considerableconcern amongst research scientists.A further problem relates to scientists beingisolated from other groundnut workers in respectof inadequate travel, difficulties in publishingscientific findings and also receivingpublications from other scientists.263

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in NigeriaS. M. Misari, C. Harkness and A. M. Fowler*ProductionGroundnut is one of the most popularly cultivatedcommercial crops in Nigeria with the bulkbeing grown in the northern states (Figs. 1, 2).The southern states produced only 1% of thetotal output in 1970-71 (Agboola 1979). TheSudan Savanna Zone (particularly in areas ofless than 1016 mm of annual rainfall) hasoptimum groundnut producing conditions.Production StatisticsIn Nigeria, they can be very misleading andalmost invariably underestimated. Productionestimates have been based mainly onpurchases by the marketing boards (MB), exportsfrom Nigeria and imports of the recipientcountries. Such figures underestimate productionsince primary producers retain unspecifiedamounts for consumption and for planting inthe next season, engage in crude oil processing,sell outside the MB system or smuggle abroadwhere businessmen take advantage of the pricedifferential between Nigeria and her neighbors.The estimates of groundnut production that issold to the MBs, for instance, range from 33 to50% of the total production (Fetuga and Ogunfowora1976).A downward trend in groundnut productionin Nigeria has been caused by several interrelatedfactors such as low producer prices, lessfarm labor due to rural population movementsto the cities, the drought years of 1971-73, theunprecedented rosette virus epidemic in 1975,an increasing incidence of rust, and higherprices for guinea corn.* Entomologist, Plant Breeder and Plant Pathologistrespectively, Institute for Agricultural Research,Ahmadu Bellow University, PMB 1044, Zaria,Nigeria.The fall in groundnut production has continueddespite an increase in guaranteed producerprice from N 68 per metric ton of kernelsin 1966-67 to N350 perm, ton in 1979-80. Thepurchasing power of N 68 in the mid 1960's isalso probably more than that of the currentproducer price of ft 350. The Central Bank ofNigeria (1974) estimated that while the producers'income for cotton in the Sudan andSahelian Zones declined from N 12.4 million toN 11.5 million between 1970-71 and 1973-74,thatfor groundnuts went from N19.2 million toN 4.1 million.These and other factors are enough challengefor Nigerian scientists to look into the problemsaffecting groundnut production.Production AreasGroundnut growing has declined sharply in theold major producing areas north of latitude12°N. During the 1970's there have been cropfailures in many places due to dry weather andother causes.In the sixties it was generally considered that33-50% of the national crop came from KanoState. It is very evident now that groundnuts nolonger produce well in the northern parts of thestate and have more or less gone out of cultivationover extensive areas. A similar situationhas arisen in other parts of the Sudan Savanna— Katsina, Daura, Azare, Nguru and Gashua,due basically to less favorable rainfall now thanduring the sixties and the decades back to the1920's. As a result of this, the major centers ofproduction of the sixties no longer exist.In the northern and southern Guinea Savannas,where rainfall is adequate for groundnuts,there are other considerations:1. Farmers may not regard groundnuts asimportant and are inexperienced with thecrop.2. The soft sandy soils of the Sudan Savanna264

allow easy harvesting even when dry.Heavier soils further south can set hardand make harvesting extremely difficult.3. Late rain frequently damages harvestedgroundnuts, and drying can be a problem.Some changes which could be made to encouragegroundnut farmers are mechanization;improved seed; crop protection; fertilizer use;cropping systems, including intercropping;supplementary irrigation on rainfedgroundnuts in northern irrigation areas; andchange in production areas. There is consider-Figure 1. Groundnut producing areas and mean annual rainfall, Nigeria.265

able scope for sound extension work in areaswhere groundnuts have not been traditionallyimportant.A project was carried out in 1976 and 1977 atHunkuyi (Zaria), with about 50 farmers whowere interested in growing groundnuts. Theywere provided with advice and seed, fertilizer,and seed dressing. Production varies fromabout 400 kg/ha pods to 3000 kg/ha. Growerswere pleased with the results and with themselves.UtilizationThe groundnut is cultivated for kernels, the oilderived from them, and hay for livestock feed.The seeds contain about 50% (45-56%)Figure 2.Land use for groundnuts.266

non-drying oil and about 30% (25-34%) protein.Because of its very high calorie content,groundnut is one of the most concentrated foodproducts. The importance of groundnuts in theNigerian diet cannot be underestimated, consideringthe inadequate protein in such diets.Five percent (Olayide et al. 1972) of theestimated 58.9 grams of crude protein availableper head per day in Nigeria (Abalu 1978) iscontributed by groundnuts. Considering thatthe estimated minimum daily requirement isabout 65 g of protein (Olayide et al. 1972),increased groundnut production can helpeliminate this protein deficiency.The groundnut is widely consumed inNigeria. Oyenuga (1968) has discussed the varioususes of groundnut and its by-products. Thekernels can be eaten fresh, boiled, dry orroasted. Most are crushed for oil and the residualcake is rich in protein and providesvaluable human and livestock food. Groundnutflour can be made by milling the cake and this isused as an ingredient in soups, stews, sauces,sweets, confectioneries, puddings and bakeryproducts.The most valuable product is the edible oilwhich comprises 50% of the total kernel. It isused for cooking, especially in northernNigeria. Other uses are for lighting, a basis ofpomade, soaps and cosmetics, salad oil, and inthe manufacture of margarine.The husks find some use as a fertilizer and soi Iconditioner. They are also used as litter forlivestock and as an absorbent in livestock feed.Industrial uses include production of pressboard and insulating materials.The haulms from which the pods have beenpicked, are a valuable livestock feed in northernNigeria.Oyenuga (1968) has summarized most of thepossible uses of groundnut (Fig. 3).Before the petroleum oil boom, groundnutwas one of the major sources of revenue andforeign exchange. Most groundnut farmersgrow groundnuts in order to sell them for cashto pay their income tax.Figure 3. Uses of groundnuts (Oyenuga 1968).267

Research ProblemsPestsGroundnut is attacked by invertebrate pests anddiseases at all stages of crop development andalso during storage. Because groundnuts in thepast were considered to be free from any majorinsect problems (Misari and Raheja 1976), researchemphasis was placed only on the rosettevirus (GRV) and its vector Aphis craccivoraKoch. Although GRV is still a major threat to theindustry a comprehensive report on pests attackinggroundnuts in northern Nigeria (Misari1975; Misari and Raheja 1976) has revealed theoccurrence and diversity of the other major andminor arthropod pests of the crop.All parts of the plant at all growth stages aresubject to attack by pests. There are soil, aerial,postharvest, and storage pests.Soil PestsGroundnuts are subject to attack by two majorsoil pests — millipedes and termites — andthree minor pests — white grubs, lepidopterouslarvae and nematodes.Thereare more than five species of millipedespresent; the most important is Peridontopygespinosissima Silvestri (Odontopygidae: Spirostreptida)(Misari 1975). The estimated yield lossdue to millipedes varies from place to place andfrom year to year (Johnson 1978; Misari 1974;Raheja 1975).The figures range from 1 to 39%but these are an underestimate of thetotal damage since the very immature podswere not examined in some cases.Termites constitute one of the most importantsubterranean pests of groundnuts inNigeria. Sands (1962 a, b) recorded damage togroundnuts, and the symptoms he describedwere similar to those found by Perry (1967).Most of the damage and loss are caused by theubiquitous small fungus grower (Macrotermitinae)belonging to the genus Microtermes(Perry 1967; Johnson et al. 1978; Wood et al.1977). Populations in excess of 4000 termites/M 2 have been recorded in Nigerian agroecosystems(Wood et al. 1977). M. subhyalinusSilvestri has been identified as one of theimportant species (Perry 1967).Amitermes evuncifer and Odontotermes sppare other termites attacking groundnuts inNigeria.Unidentified species of lepidopterous larvae(Perry 1967; Johnson 1978) and white grubs(Scarabaeidae) have been observed to attackgroundnut but they are important only inlocalized areas.To date, nematodes have not been incriminatedas economically significant pests ongroundnut in Nigeria. Only two species appearto be potentially important. The groundnut-podnematode, Pratylenchus brachyurus, also calledthe lesion nematode, can kill young seedlings.A species of Ditylenchus has also beenreported as attacking pods but always at verylow incidence. Bos (1977) described a newspecies called the seed testa nematode,Aphelenchoides arachidis (Bos).Over eleven nematode species have beenfound associated with groundnuts includingHelicotylenchus dihystera, Scutellonema clathricaudatum,Creconemoides spp, andPratylenchus zea.Aerial PestsOf the more than 70 insect species associatedwith the groundnut crop in northern Nigeria(Misari and Raheja 1976) only a few are thoughtto be economically or potentially serious asshoot and foliage pests. These include thecowpea or groundnut aphid, Aphis craccivoraKoch; several species of cicadellid leafhoppersnotably the cotton jassids, Empoasca dolichiPaoli and Jacobiella fascialis Jac; thegroundnut leaf beetles, Monolepta spp; andLuperoides quaternus Frm; and to a considerableextent flower feeding blister beetles andthrips also becoming more important.APHIS CRACCIVORA KOCH AND THE ROSETTEVIRUS. This is the most important pest in thiscategory. It is a sap feeder and although a heavyattack can result in wilting and death of the cropespecially in hot weather, it is a more seriouspest as the vector of the groundnut rosette virus(Zimmerman 1907; Storey and Bottomley1925).The groundnut rosette virus disease and itsaphid vector, A. craccivora have been reportedin Nigeria for over 50 years (Harkness 1977). Thedisease symptoms in Nigeria (Rossel 1977) aresimilar to those described in other countries butthe form of rosette most commonly found in268

Nigeria is the "green rosette." Symptoms arevariable but a downward and inward rolling ofthe leaf margins is highly characteristic of thegreen rosette (Harkness 1977). The chloroticrosette form is of rare occurrence and is characterizedby bright yellow to white interveinalchlorosis, crinkling, twisting and stunting of thefoliage and shoots.In 1957, research work on the aphid/rosetteproblem began in Mokwa. Here, A' Brook (1964,1968) showed that early planting and closespacing achieved control of rosette disease.Booker (1963) reported similar findings inSamaru.The rosette epiphytotic in 1975 was the worstrecorded in the history of groundnut productionin Nigeria. It destroyed about 0.7 million hectaresof groundnuts in the Sudan and northernGuinea Savannas and so revealed the vulnerabilityof the total crop and the need for resistance(Yayocketal. 1976). Because an estimated80% of the national groundnut productionmay come from these zones and nearly allthe remainder comes from the southern GuineaSavanna (Harkness et al. 1971), the need forintensive research into the causes and controlof the rosette disease cannot be overemphasized.CAUSES OF THE 1975 ROSETTE EPIDEMIC. It is stillnot fully understood why the 1975 epidemicoccurred (Yayock et al. 1976, 1978; Akinfewa1978) but some or all of the following factorsmay have been responsible:1. Research efforts on rosette-resistant varietieshad been concentrated for theriverine areas where rosette consistentlycaused more significant losses than in thenorth. While the current recommendedresistant varieties (M25.68 and ex-Bambey69-101) arelong season and most suitablefor the riverine areas, those grown in thenorth are short season and less resistant.2. Aphid populations and the number ofprimary rosette infection loci were extraordinarilyhigh in both the epidemicregions of the main groundnut productionarea in the north and the riverine areas inthe south where no epidemics occurred.Since crop seasons in Nigeria are dependentupon the rains which move as a beltup and down with the intertropical discontinuity(ITO), Feakin (1967) postulated thatrosette and its vector could move over thegroundnut growing areas with the prevailingrain bearing southwest to northeastmonsoon winds (Fig. 1). Benoit(1977) hascomputed the advance of rainy season atvarious latitudes in northern Nigeria.3. Earlier widespread groundnut plantingstook place in riverine areas together withsporadic plantings in the north. As therains permitted, early plantings continuedin the north so that by mid-May there was aspread of groundnuts of various ages fromsouth to north. This led to an early dispersalof aphids and the virus from south tonorth. A secondary spread of the virusthen overwhelmed thecrop over extensiveareas.4. The mild dry season and early rainfall mayhave assisted the carry-over of rosetteinfected groundnuts, especially in thefadama and irrigation areas of the northerngroundnut growing areas. The occurrenceof abnormally long periods ofdrought in many areas just afteremergence of the groundnut crop enhancedthe build-up and dispersal of aphidcolonies. This may have led to a zonalbuild-up of rosette virus reservoirs (Rossel1977) and a rapid secondary spread of thevirus disease.The role of weather in the epidemiology andpopulation dynamics of the virus and the aphidsis being investigated.APHID AND ROSETTE PROBLEMS IN NIGERIA. Althoughvirus material collected in Nigeria hasbeen studied in England, by Okusanya andWatson (1966) who confirmed its identity asgroundnut rosette virus, little is known of theproperties of the causal virus or viruses. Hulland Adams (1968) and Okusanya and Watson(1966) found that isolates from East Africa andfrom Nigeria are sap transmissible.Their host range and vector studies revealedtwo components — a symptom inducing component(GRV) being sap transmissible and asymptomless component, being aphid transmissibleonly. The sap transmissible componentwas found to be aphid transmitted onlywhen in combination with the symptomlesscomponent, and hence the designation of thelatter as groundnut rosette assistor virus(GRAV) (Hull and Adams 1968).269

It is not known if the two-component nature ofthis virus plays a significant role in theepidemiology of the disease.All efforts to find natural off-season hosts(other than groundnuts) of the virus have failed.Since the virus is not seed transmissible, andsince the groundnut crop is only of rare occurrenceduring the dry season, work still continuesin search of the carry-over mechanism of thevirus from one season to another. Akinfewa(1977) has tentatively identified the rosette vector,A craccivora on over 60 wild and cultivatedplant species in ten families. About 24 of thesespecies (15 wild and 9 cultivated) belong to thegroundnut family Papilionaceae.Since the majority of the wild hosts andgroundnut volunteers are found in fadamaareas and irrigation sites of the northern states,it appears thatthe hypothesis of a south to northmovement of virus/vector complex has to bereviewed.Recent observations have shown an increasingprevalence of the chlorotic rosette in additionto the usual green rosette. Some virus-vectorrelationships of the green rosette fromNigeria and the chlorotic rosette from EastAfrica were studied in England by Okusanya(1965). Her work showed that a Nigerian race ofA. craccivora transmitted both green andchlorotic rosette, whereas races from Ugandaand Kenya, which transmitted chlorotic rosette,failed to transmit green rosette. There has beenno report of comparative virus-vector relationshipsof the symptomatically different types ofrosette viruses occurring in Nigeria.Present studies at the Institute for AgriculturalResearch, Samaru, Nigeria have indicated thatthey are both transmitted by A. craccivora. Anattempt is being made to find out if they aredifferent strains of the same virus and what isthe epidemiological significance.CICADELLID LEAFHOPPERS. These insects arefound throughout the cropping season. Theirfeeding damage can be quite serious and workis in progress to evaluate the losses caused bythem.GROUNDNUTLEAF BEETLES. The adults chew orpuncture the leaves but do not cause as muchdamage as the cicadellid leafhoppers.BLISTER BEETLES.They are known to causeheavy damage to groundnut flowers; thespecies involved are Coryna hermanniea F.;Mylabris trifasciata Thunbs; Decaptoma affinisOliv. and Epicauta spp (Misari and Raheja 1976;Raheja and Misari, in press).Postharvest and storage pestsThe decline in groundnut production in Nigeriais greatly amplified by losses incurred at andafter harvest, especially in storage. Severalinsect species are responsible for heavy lossesof postharvest groundnuts due mainly to theinadequate storage facilities of farmers and tothe ignorance of the government agenciesabout the need for entomologically sound storagedepots. Over 40 storage insect pests havebeen reported as infesting groundnuts in store(Comes 1964).The major storage pests are the groundnutseed beetle (Caryedon serratus F.); flat grainbeetle (Cryptolestes ferrugineus Steph.);khapra beetle, (Trogoderma granarium Ev.);merchant grain beetle (Oryzaephilus mercatorFaur.); red rust flour beetle {Tribolium castaneumHerbst); confused flour beetle(Tribolium confusum); tropical warehousemoth (Ephestia cautella Wlk.); rice moth (Corcyracephalonica Staint.); Aphanus sordidus F.;and Indian meal moth (Plodia interpunctellaHub.).All told, a groundnut producer experiences5-35% damage to his crop annually frominsect pest attacks in Nigeria. At present, it iseconomically unrealistic to recommend theroutine use of pesticides.WeedsThey constitute one of the greatest bottlenecksto production (Musa and Kaul 1978). Generallythere is about 18-70% (average 50%) lossfrom weeds recorded in Nigeria.The parasitic species Alectra vogelii Benth. ofthe family Scrophulariaceae is a major threat togroundnut producers. This parasitic floweringplant causes yellowing of the foliage and poorpod set and seed development. It attacks thegroundnut root system and taps the host'snutrient energy source through a conspicuousknot which is formed at its point of attachmentwith the host.The pest appears to be widespread th rough-270

out the producing areas where its deleteriouseffect is becoming increasingly recognized. Theassessment of yield loss due to this parasite andits control remain to be determined.DiseasesSevere damage was done to 0.7 million ha byrosette virus in 1975. South of 11!/ 2 ° northlatitude, leaf spots cause pod losses of20-50% everywhere each year. In 1976 peanutrust appeared.Seedling wilts are serious locally but wilts ofolder plants have not been so. Pod rots havebeen significant in some fields at Samaru insome years. No work has yet been done withresistant varieties.No progress has been made on resistance toaflatoxin. The need is greaterthan before, with aplanned expansion of crop in the northernGuinea Savanna. The only large commercialcrop bought was in 1972 (half a million m.tons), and this had acceptably low aflatoxinlevels. It was a favorable season however, withgood drying weather after harvest for mostgrowers.RustThe disease is now endemic in the country andhas become more damaging each year since itappeared in 1976. So far no significant attackhas been recorded north of 11 Y 2 °N latitude, butsouth of it there is now widespread and seriousdamage.Rust was severe at many sites in 1980 especiallyin the southern and western areas. It hasbeen observed many times that rust is lesssevere in late planted crops.Leaf SpotsControl of the Mycosphaerella early and lateleaf spots remains a major objective. For mostfarmers, medium volume spraying is not practicaland VLV and ULV techniques are insufficientlyresearched. Spraying would be requiredto control rust as well as leaf spots.The following species have shown resistancein the field: Arachis chacoense against Cercosporaarachidicola (early); and A. cardenasiiagainst Cercosporidium personatum (late). Anun-named species HIK 4.10 (Hammons,Langford and Krapovickas collection), andUSDA introduction number PI 338280 haveshown some resistance to both leaf spots.No effective field resistance to leaf spots hasbeen established from crosses made to date. Avariety needs resistance to both leaf spots to besatisfactory. Usually both are present at highlevels but with great variation in proportion toeach other, from spot to spot within the field,between fields, sites and seasons.It is possible that races of the leaf spots maybe present. The leaf spots cause by far thegreatest losses of yield which groundnut growerssuffer.RosetteThe groundnut rosette virus disease is by farthe most damaging virus disease of the crop inNigeria. The form of the disease is "NigerianGreen Rosette". "Chlorotic Rosette" also occursat a low incidence level.Rosette disease in the past has caused moredamage south of latitude 11°N than in the mainproducing areas which lie north of it.Losses due to rosette are estimated to be3% per year from all groundnuts grown in theSudan and northern Guinea Savanna Zones.Early planting and close spacing aresafeguards against rosette, ft is not alwayspossible to achieve and it is not effective againstepidemics like the 1975 outbreak. Rosette resistantvarieties are needed to keep the disease incheck and insure growers against one of thehazards of the crop.Effective resistance has long been recognizedin collections from Upper Volta, Cote d'lvoires,Cameroun and other places. It has not beenfound in Nigeria. The CNRA Bambey, Senegallines have proved to be highly resistant to theNigerian Green Rosette and recent screeninghas shown that lines resistant to green rosetteare also resistant to Nigerian chlorotic rosetteand vice-versa.It is not difficult to incorporate rosette resistanceinto acceptable varieties with a range ofseason lengths. Recent introductions from theUpper Volta Program (RMP 12, RMP 91) haveproved highly resistant and very productiveover many sites in the northern and southernGuinea Savannas. No satisfactory rosette resistantlines are at present available in Nigeria and271

work continues to improve the Upper Volta lineKH 14-9A. Rosette resistant, drought material isneeded forthe northern areas where the uplandcrop is at risk from aphids associated withirrigation projects.Pod Set FailureThe problem of blind or unfilled pods (Yayock1979) is extensive. In 1978 there were widespreadcrop failures where vegetative growthwas good, but hardly any pods developed.The causal factor(s) for blind or unfilled podsis not known. Items which have been investigatedare insect infestations, disease, late plantingand weather. Rainfall, moisture stress,temperature levels and diurnal differencescould be involved and linked with nutrientuptake and transport.ReferencesABALU, G. 0. I. 1978. An economic analysis ofgroundnut production In the northern Nigeria.Pages 83-90 in Proceedings of the National Seminaron Groundnut Production, Kano, Nigeria, Feb 1978.A'BROOK, J. 1964. The effect of planting date and spacingon the incidence of rosette disease and of thevector. Aphis cracclvora Koch, at Mokwa, NorthernNigeria. Annals of Applied Biology 54: 199-208.A'BROOK, J. 1968. The effect of plant spacing onnumber of aphids trapped over groundnut crop.Annals of Applied Biology 61: 289-294.AGBOOLA, S. A. 1979. An agricultural atlas of Nigeria.Oxford University Press. 248 pp.AKINFEWA, S. 1977. Report on aphid and groundnutrosette project. Groundnut conference, Kano, 1977.AKINFEWA, S. 1978. Aphis cracclvora Koch and rosettevirus disease of groundnuts in Nigeria. NigerianGroundnut Board. 1978.B ENOIT, P. 1977. The advance of rainy season in northernNigeria. Samaru Agricultural Newsletter19: 61-66.BOOKER, R. H. 1963. The effect of sowing date andspacing on rosette disease of groundnuts in northemNigeria, with observations on the vector, Aphiscracclvora. Annals of Applied Biology 52: 125-131.Bos, W. S. 1977. Aphelanchoides arachidis n. sp(Nematode: Aphelenchoidea), an endoparasite ofthe testa of groundnuts in Nigeria. Journal of PlantDiseases and Protection 84: 95-99.CORNES, M. A. 1964. A revised list of the insectsassociated with stored products in Nigeria. Pages31-34in Nigerian Stored Products Institute, AnnualReport 1964, Technical Paper No. 4.FEAKIN, S. (ed.) 1967. Pest control in groundnuts.PANS Manual No. 2; 1st Edition. 192 pp.FETUGA, B. L, and OGUNFOWORA, 0.1976. The supplyand utilization of some major oilseeds and oilseedcakes in Nigeria. Nigerian Journal of Animal Production.3: 43-52.HARKNESS, C. 1977. The breeding and selection ofgroundnut varieties for rosette disease in Nigeria.Text submitted as an entry for the AfricanGroundnut Council Prize for 1977,45 pp.HARKNESS, C, KRIESEL, H. C, and DAGG, M. 1971.National Agricultural Development Committee. 2.Report of the study group on groundnuts. Nigeria,Federal Department of Agriculture, Lagos.HULL, R., and ADAMS, A. M. 1968. Groundnut rosettevirus and its assistor virus. Annals of Applied Biology62: 139-145.JOHNSON, R. A. 1978. Soil pests of groundnuts inNigeria. Proceedings of the National Seminar onGroundnuts Production, Kano, Feb 13-14, 1978, 7pp.JOHNSON, R. A., AKINFEWA, S., and RAHEJA, A. K. 1978.Pre- and post-harvest crop protection pests ofgroundnuts in northern Nigeria. Paper prepared forthe Third General Conference of Association for theAdvancement of Agricultural Sciences in Africa,Ibadan, Nigeria, April 9-15,1978. 15 pp.MISARI, S. M. 1974. Report on Groundnut Entomologyfor the 1974 season to the Board of Governors of theInstitute's Work 1974-1975. Groundnuts andOilseeds Improvement Programme; I.A.R./ABUSamaru, Zaria, Nigeria.MISARI, S. M. 1975. Insects and other arthropod pestsof groundnuts in Northern Nigeria. AgriculturalNewsletter 17(1): 4-9.MISARI, S. M. and RAHEJA, A. K. 1976. Notes on fieldpests of groundnuts In northern Nigeria. InternationalSymposium of Field Pests of Groundnutsand Millet, Kaolack, Senegal, 21-23 April, 1976.66-79 pp.272

MUSA, H. L, and KAUL, R. N. 1978. Weed controlstudies on groundnuts with reference to selectedequipment and systems. Pages 59-64 in Proceedingsof the National Seminar on Groundnut Production,Kano, Feb 13-14,1978.OKUSANYA, B. A. M. 1965. Page 129 in RothamsteadExperiment Station Report 1964.OKUSANYA, B. A. M., and WATSON, M. 1966. Host rangeand some properties of groundnut rosette virus.Annals of Applied Biology 58: 377-387.OLAYIDE, S. O., et. al. 1972. A quantitative analysis offood requirements, supplies and demands inNigeria, 1968-1985. Federal Department of Agriculture,Lagos.OYENUGA, V. A. 1968. Nigerian feed and feeding stuffs.Their chemistry and nutritive value. Ibadan UniversityPress. 99 pp.PERRY, D. A. 1967. Premature death of groundnutplants in northern Nigeria. Experimental Agriculture31: 211-214.R AHEJA, A. K. 1975. Millipedes on groundnuts,4racri/shypogaea L. Nigerian Journal of Plant Protection1(1): 91-92.RAHEJA, A. K., and MISARI, S. M. (Submitted to Press).Pests of Groundnuts. A chapter in Pests of Crops inAfrica, H. F. Van Emden, S. R. Singh and T. A. Taylor(eds.), John Wiley and Sons.ROSSEL, R. W. 1977. Some observations and experimentson groundnut rosette virus and its control inNigeria. Samaru Conference paper 9.SANDS, W. A. 1962a. Technical Report of the RegionalResearch Station, Ministry of Agriculture, NorthRegion, Nigeria. 26.SANOS, W. A. 1962b. The evaluation of insecticides assoil and mound poisons against termites in agricultureand forestry in West Africa. Bulletin ofEntomological Research 53: 179-192.STOREY, H. H., and BOTTOMLEY, A. M. 1925. Transmissionof rosette disease of the groundnut. Nature,London 116: 97-98.WOOD, T. G., JOHNSON, R. A., and OHIAGU, C. E. 1977.Populations of termites (Isoptera) in natural andagricultural ecosystems in Southern GuineaSavanna, near Mokwa, Nigeria. Geo-Eco.-Trop.1: 139-148.YAYOCK, J. Y., ROSSEL, H. W.,and HARKNESS. C. 1976. Areview of the 1975 groundnut rosette epidemic inNigeria. Pages 129-137 in the African GroundnutSymposium on Pests of Groundnuts and Millet inthe Field; Kaolack, Senegal, 21-23 April, 1976.YAYOCK, J. Y., HARKNESS, C, and JOHNSON, R. A. 1978.Groundnuts: What went wrong in 19787 FDAGroundnut Rehabilitation Committee, March 1979.Institute of Agricultural Research, Samaru, Nigeria.Reports to Board of Governors.ZIMMERMAN, A. 1907. A disease of peanuts, Arachishypogaea L. Pflanzer, 3: 129-133.273

Groundnut Production and Research in SenegalJ. Gautreau and 0. De Pins*ProductionGroundnuts constitute the main cash crop ofSenegalese agriculture, with most of the productionbeing turned into peanut oil. They playan important role in the economy of the country,even though during the last few yearsemphasis has been placed on the developmentof food crops. They represent between onethirdand one-half of the total exports fromSenegal.The groundnut basin covers an area of approximately3 million hectares of which, on theaverage, 1.1 million ha are sown withgroundnuts every year. During the last twodecades the area planted has remained fairlystable, whereas the yields have fluctuated dependingon theincidenceof droughtperiods. Asa result, crop production has varied greatly(Table 1). The record production in 1975 exceeded1.4 million metric tons. The 1980 cropseason is being compromised by the significantlylate arrival of the rains.The priority aim of the Senegalese Governmentis to stabilize groundnut production at amaximum limit of 1.2 million metric tons ofunshelled groundnuts. This regulation wouldminimize the fluctuation in metric tons exported,and consequently stabilize the annualincome of the producers.Organizations and Assistanceto FarmersThe farmers are grouped into cooperativeswhich supply them with production inputs andgather products such as groundnuts at the locallevel.Several organizations cooperate for aid anddevelopment in the rural sector (Sene 1980).Briefly they are:* Institut Senegalais de Recherches Agricoles (ISRA),National Agronomic Research Center (CNRA), BP51, Bambey, Senegal.1. SONAR, a new national organizationwhich supplies the farmers and managesthe seed capital.2. SODEVA, a regional society for rural development,which operates within thegroundnut basin. It is in charge of allproduction activities and provides technicaland cooperative assistance for thegrowers.3. The CERP centers (multi-purpose centerfor rural expansion) have an important aidrole at the rural community level, in strictcooperation with the regional society fordevelopment. They provide the localpeople with technical services.4. The National Seed Service created in 1972produces, controls and looks after the seedcapital. Its role is particularly important forgroundnuts especially because the annualrequirement of recommended seeds is ofthe order of 100-130 000 t (Lam andDelbosc 1977).Climate and Soil ConditionsSenegal at the western tip of Africa, is under theinfluence of the Sahelo-Sudanian climatecharacterized by a single rainy season, usuallyshort, and interrupted by frequent periods ofdrought. Lack of water has been the mainfactor limiting production in a large part of thegrowing zone for 10-12 years.The north-south rainfall gradient is very significant:1000 mm in 5 months in the Casamanceand 300 mm in 2.5 months in the north(Mauboussin 1973). Due to the recent years ofdrought, there has been a disturbing slippageof isohyets towards the south and a shorteningof the period of useful rains. The consequencesare serious in the northern half of the country, azone where groundnuts are suffering more andmore, often from lack of water.The groundnut growing soils have a sandy274

Table 1. Peanut oil production in Senegal, 1960-1977.Area Production YieldCrop season (000 ha) (00 tons of unshelled peanuts) (kg/ha)1960-61 975 890 9151961-62 1025 995 9701962-63 1015 915 9001963-64 1085 950 8801964-65 1055 1020 9651965-66 1115 1120 10051966-67 1115 855 7701967-68 1165 1005 8651968-69 1190 830 6951969-70 955 790 8301970-71 1050 585 5551971-72 1060 990 9301972-73 1070 570 5301973-74 1025 675 6601974-75 1050 980 9301975-76 1205 1410 11751976-77 1345 1210 8951977-78 1115 520 465Average 1190 905 830Standard 93 227 184deviationCV

276

the last few years significant millipede damagehas been observed at emergence time andduring the pod formation.Various groundnut leaf diseases exist. Cercosporaleaf spot can have a serious impact inthe southern part of the country. Groundnutrust appeared in 1978-1979 but with noeconomic consequences up until now.The problem of seed contamination by Aspergillusflavus has existed for several years.The formation of mycotoxin is encouraged bythe more and more frequent periods of droughtoccurring during the maturing stage. Until resistantvarieties become available, Senegal hasstarted a pilot industrial unit for the chemicaldetoxification of peanut meal, and is experimentingwith various electronic screening proceduresfor seeds.VarietiesThe climatic conditions prevalent in Senegalnecessitate the use of varieties adapted to therainfall constraints. The maturity cycles rangefrom 120 to 130 days in the south, to 90 days atthe northern limit of the cultivation zone. Continuousbreeding research has enabled thecreation of several varieties which are betteradapted to the various ecologies (Gautreau1980). Most of the groundnut varieties croppedin Senegal were recommended by research.In the south, 69-101 is a Virginia varietyresistant to rosette and derived from the28-106 variety for which the cultivation zone isfurther north (Fig. 2). In the center, and northcentralregions, 73-33 is a new drought resistantvariety with a 105-day maturity cycle. It hasbeen released recently (until resistant varietiesbecome available), and will be cultivated onapproximately 260 000 ha. The 55-437 variety isa 90-day Spanish commonly grown in thenorthern part of the basin. Its nondormancylimits its expansion to the south where a newvariety with the same cycle, but dormant, iscultivated. The 57-422 variety is a Virginia typewith large seeds and a 105-day maturity cycle.Lastly, GH 119-20 of American origin is cultivatedfor edible peanuts in the Sine-Saloumregion.Groundnut Researchand ObjectivesThe first research in Senegal was conducted inFigure 2.Migration of the isohyets in Senegalfrom 1931-1977.277

the twenties. In 1975, the various organizationswhich were involved in agricultural researchtransferred to a national organization — theSenegalese Institute for Agricultural Research(ISRA) under the guidance of the Ministry ofScientific and Technical Research (SERST). Researchis carried out in stations all around thecountry and in the multilocation experimentalfields in the farmers' environments.G r o u n d n u t B r e a d i n gThe breeding objectives of the SenegaleseInstitute for Agricultural Research (ISRA) areimprovement to drought; resistance to rust,leaf spot, and Aspergillus flavus; and the creationof edible peanut varieties and peanuts forconfectionery use.Improvement of GroundnutResistance to DroughtThe decrease of rains in the Sahel has causedbreeders to create varieties better adapted todrought (47-16, 50-127, 73-33, 55-437) whichhave shown good performances in dry conditions(Bockelee-Morvan at al. 1974). To do this,the two breeding and physiology divisions ofthe National Agronomic Research Center(CNRA), in Bambey, collaborate very closely.The two methods being used are shortening ofthe growing cycles (using the parent "Chico"),and screening lines or varieties with a goodtolerance to drought.In addition to research on better adaptation todrought, different types of improved yieldmaterial are being screened (Tables 2,3,4, 5).Breeding for Resistance to Rust(Puccinia arachidis Speg.)This new program has been designed tocounter the threat resulting from the recentappearance of groundnut rust in West Africa.The incidence of this disease in crops varies; itdepends on how early the invasion commences.It has been possible (1) to obtain the mainsources of resistance, DHT 200, Tarapoto,Israel line 136, and FESR lines 1-14 promotedby the USDA; (2) to verify in Upper Volta theirresistance to the type of rust common in WestTable 2. Variety trial results, Bambey (average yields of poda In k g / h a ) .MaturityVarieties (days) 1975 1976 1977 1978 1979 Average55-43773-3073-3357-4223125 25302125 2250 2200 244590 2745 2390 2160 1770 22653965 2600 2040 2120 2115 2570105 3245 2960 2120 2330 2210 2575Table 3. Variety trial w i t h yields expressed as a percentage of the best control lines (10replications/variety = 105 m V v a r l e t y ) .Lines Origin 1977 1978 1979V37 (28-206 x 48-115) 57-422 2 112 109 118V 41 " 118 102 103V 55 " 115 116 147V 58 " 114 107 108V 59 " 108 110 103V 79 55-437 (48-115 x 28-206) 114 107 100V 755 55-437 x 57-313 107 100 108Note: The V 755 variety called 79-2 is likely to replace 57-422 (superior yield of 5% In station experiment*; shelling rate •good seed rate = 5.5%, 100-karnel weight - 60-65g.)1.7%;278

Africa; and (3) start a complete breeding programto transfer these resistant genes to thereleased varieties.Recently, a fruitful exchange of plant materialwith ICRISAT permitted the use of two newparents NC-Acc 17090 and EC 76446 (292) forcross-breeding. It also provided the first segregatinggenerations of 45 families of crossbredvarieties for resistance to rust. The screening ofthese different progenies should start with the1981 crop season. However, since the disease isstill not very prevalent in the country, oneTable 4. Average yield (pods kg/ha) in Bambey of some recent introductions; varietalexperiments — 10 replications; 147 m 2 variety.Introductions 1976 1977 1978 1979 AverageTG 7 (India) 2640 2050 2345TG8 " 2425 2575 1670 2225TG 9 " 2425 2615 1585 2210TG 14 " 2225 1980 2100Faizpur (India) 2810" 2015 1930 2050 2200UF 72-101 (USA) 2650* 1880* 2210 1985 2180UF 73-217 " 1990 2505 2275 2255Early runner 2215 2175 2195Comet 1815' 2005 a 2205 2250 2320Spanhoma 3010 a 2490 2115 2110 2430Spancross 2205 a 2215 2145 2190Florunner 2725 1710* 2315 2270 2255Starr 2890 a 2400* 1870 2385Egret 1900 1350 162555-437 2665 b 2125 b 2105 b 2130 225557-422 2850 b 2235 d 2465 c 2110 b 241573-33 1940 b 2060 d 2095 c 2025* 2280a. Varietal trial with 4 replications.b. Average of 2 varietal trials.c " 3 "d. " 5 " "Table B. Average yield (pods kg/ha) of some introductions tested near Louga. Uoltyet = 300 m m ;experiments w i t h 7 replications-84 mVvariety.Varieties 1975 1976 1977 1978 1979 AverageArgentine 560 900 105 920 155 530Starr 305 885 90 1060 195 510Spanhoma 525 765 55 900 560Tifspan 510 885 70 860 580Spancross 245 940 110 1380 110 560Comet 350 880 80 1185 105 540Florispan 385 720 70 1230 130 510Faizpur 80 945 135 385Chico 355 35 425 75 22073-30 340 730 90 1070 150 47555-437 385 815 95 1180 180 530Rainfall (mm) 317 289 169 326 223279

foresees that, for the time being, the breedingmethods will be limited to laboratory tests in aclosed area, such as with the test of inoculationof leaves maintained on Hoagland mediums(Subrahmanyam et al. 1980). For securityreasons, it is intended to avoid the use ofbreeding methods involving artificial contaminationin open fields.Breeding for Varietal Resistanceto Leaf Spot (Cercospora personata)Results of experiments carried out in southernSenegal (Casamance) show that this diseasecan bring about a loss of 30-40% in yield. As oftoday, there is no effective solution to thisdisease. The main problem is the lack of geneticvariability with regard to this characteristic inthe Bambey collection. A search for possiblesources of resistance is under way at the presenttime.Varietal Resistanceto Aspergillus flavusLinkResearch in this field is extremely importantbecause of the serious consequences for thehealth of people and animals due to the presenceof aflatoxin in the seeds and peanut meal.The economic importance is easily understoodsince 300 000 tons of peanut meal are exportedfrom Senegal every year which must satisfy therecent norms of the importing countries — lessthan 50 parts per billion.The breeding program in Bambey against A.flavus is at the F 5 stage. The parents used arethose received from the USDA and identifiedby Mixon and Rogers —PI 337 409 and PI337 394.The two selection tests used are (1) inoculationin Petri dishes (Zambettakis et al. 1977)and (2) measuring the aflatoxin content by theVelasco method. A third test based on themeasurement of the seed coat permeability toions has been evaluated for its reliability (Camera1977). Its first results seem to correlate withthose of the artificial inoculation test which ismore involved.The early variety 55-437, cultivated throughoutthe northern part of the groundnut basin,shows as equally good resistance to A. flavus asthe two USDA parents used.The thickness and hardness of the shell aswell as an appreciation of the texture of theseed coat are also used (Zambettakis andBockelee-Morvan 1976; Waliya and Abadie1978) as criterion of resistance. This research iscarried out in collaboration with the Museum ofNatural History in Paris.Creation of Edible Confectionery VarietiesSenegal hopes to achieve more valuablegroundnut production by increasing the cultivationof edible and confectionery peanuts forexportation through a favorable and expandingmarket.Such varieties must fit the technologicalnorms specified at the level of various channels.Generally one tends to get a well-formed, constrictedpod with large and round seeds. A goodrepresentative type is GM 119-20 coming fromthe United States. Variety 756 A is also grown inSenegal. It will soon be replaced by the new73-27 (GH 119-20 x 756 A) which scores betterin grade and productivity.Certain Spanish varieties such as 55-437,75-33, and 75-50 (Faizpur) correspond well withthe Hand Picked Standard (HPS) norms for theconfectionery peanut market.A g r o n o m yLong-term studies have been carried out in theCNRA by multi-disciplinary teams in farmingtechniques, soil management and root-growthsystems; crop rotations and farming systems;fertilization and rhizobiology; and agroclimatology.Bioclimatology studies are particularlyneeded to evaluate the water requirements ofgroundnuts (Dancette and Hall 1979).C r o p P r o t e c t i o nWork is being conducted on the screening of thebest efficient insecticides to control the maingroundnut pests: millipedes (Odontopygidae),termites (Eutermes parvulus), larvae (Amsactamoloneyi and Spodoptera littoralis), bugs(Aphanus sordidus), and bruchids (Caryedonfuscus); selection of active nematocides; screeningof active leaf fungicides mainly againstrust and Cercospora leaf spot; testing of variousherbicides; studies on stock protection; andpesticide residue studies.280

P o s t h a r v e s t T e c h n o l o g yThe main subjects being studied in collaborationwith industry and various organizationsare: grading of edible and confectionery peanuts;electronic screening of seeds contaminatedwith A. flavus; detoxification of peanut mealwith gaseous ammonia; and studies on storagemethods, both cold storage or vacuum packs.ConclusionGroundnuts have constituted an essential resourceof the Senegalese economy for a longtime, but the average production for the last 20years still falls very short of the 1.2 milliontonnes o p t i m u m levels set by the authorities.This situation is mainly due to more and morefrequent years of a significant lack of rainfalland an appreciable delay between the establishedcultural techniques suggested byresearch and the more or less improved traditionalpractices of most of the producers.Tangible results were obtained due to theactivities contributed by the agricultural aidorganizations. However, a great deal of work isstill necessary. The recent administrative reformshould make it easier. On the other hand, itis up to research to prove a renewed d y n a m i s mto face new calamities w h i c h threaten the incomeof groundnut producers (drought, rust,Cercospora leaf spot, aflatoxin) and to cooperateeven more closely with the agricultural aidservices.ReferencesBOCKELEE-M ORVAN, A., GAUTREAU, J., MORTREUIL, J. C,AND ROUSSEL, O. 1974. Results obtained withdrought-resistant groundnut varieties in WestAfrica. Oleagineux 29(6): 309-314.CAMARA, P. A. 1977. Permeability testing of the thinskin of groundnut seeds. Oleagineux 32(6): 273-276.CHARREAU, C. 1961. The dynamics of water in twotypes of soil in Senegal. Agronomie Tropicale16(5): 504-562.DANCETTE, C, and HALL, A. E. 1979. Agroclimatologyapplied to water management in the Sudanian andSahelian zones of Africa. In Agriculture in semi-aridenvironments. Ecological studies Vol. 34.GAUTREAU, J., 1977. Levels of intervarietal leaf potentialand adaptation of groundnuts to drought.Oleagineux 32(7): 323-331.GAUTREAU, J., GARET, B., and MAUBOUSSIN, J. C. 1980.A newvariety of Senegalesegroundnuts, adapted toperiods of drought: variety number 73-33.Oleagineux 35(3): 149-154.LAM, M., and DELBOSC.G. 1977. A tool for developmentcreated in Senegal: the seed service. Oleagineux32(1): 15-19.MAUBOUSSIN, J. C. 1973. The objectives of varietalimprovement in the face of environmental constraints.Colloque de Rufisque, Janvier 1973.MIXON, A. C, and ROGERS, K. M. 1973. Peanut resistantto seed invasion by A. flavus. Oleagineux28(2): 85-86.SENE, D. 1980. On reform and redynamization of aidstructures in the rural sector. Ministers du developpementrural du Senegal, April 1980.SUBRAHMANYAM, P., GIBBONS, R. W., NlGAM, S. N.,and RAO, V. R. 1980. Screening methods and furthersources of resistance to peanut rust. Peanut Science7: 10-12.WALIYAR, F., and ABADIE, M. 1978. The penetrationof mycelium of Aspergillus flavus Linkinto the groundnut seed coat after artificialcontamination — ultrastructural analysis.Oleagineux 33(8): 447-453.ZAMBETTAKIS, C, and BOCKELEE-MORVAN, A. 1976. Researchon the seed covering of groundnut seeds andits influence on penetration by A flavus. Oleagineux32(5): 219-228.ZAMBETTAKIS, C, BOCKELEE-MORVAN, A., WALIYAR, F.,and ROSSION, J. 1977. Varietal differences ingroundnut sensitivity to contamination by A flavus.Oleagineux 32(8): 377-385.281

Groundnut Productionand Research Problems in the SudanH. M. Ishag, M. A. Ali and A. B. A h m a d i *ProductionGroundnut is an important cash crop in theSudan, the largest country in Africa. It provides7% of the GNP and employs 12% of the population.Sudan is the fourth leading country ingroundnut production after India, China, andthe United States. Production has increased bya bout 320% since 1965. The three major regionsof groundnut production are Gezira and Managil(42%), North Kordofan (17%) and SouthDarfur (14%). The average pod yield is low,being 600 kg/ha in rainfed areas and 1440 kg/hain irrigated areas.There are several distinctive climatic regions.In the north, temperatures are high and rainfallis scanty and irregular, while in the southrainfall is heavy — up to 1400 mm. Soils areclassified into four groups (Said and Mustafa1978) — (a) soils of the central clayplain, (b)sandy soils of western and northern Sudan, (c)desert soils and sands of the northern half of theSudan, and (d) alluvial and riverine soils alongthe Nile and its tributaries. The total area suitablefor cultivation is about 200 million feddans.There are 16 million feddans under cultivationof which only 4 million are irrigated. (Onefeddan =1.04 acres = 0.42 ha.)Crop ManagementRainfed AreasIn sands of the western region of Sudan, theearly maturing variety Barberton is sown byhand when the rains start This variety maturesin about 100 days. Seed dressing with Aldrex Tis practised by most of the farmers. Plantpopulation is low. No fertilizers are used and* Agricultural Research Corporation, Wad Medani,Sudan.weeds are controlled by hand. Proper rotationsare not followed and shifting cultivation is thenormal practice. Crops grown with groundnutsare sesame, roselle [Hibiscus sabdariffa L.) andmillet.Irrigated AreasGroundnut in irrigated areas is normallyplanted in June in a row spacing of 80 cm withabout 30 cm between plant holes and with 1-2seeds per hole. Different rotations are adopted;in Gezira, a four course rotation (cottonwheat-groundnuts/sorghumor rice-fallow); inManagil, a three-course (cotton-wheatgroundnuts/sorghum);and in Suki and Rahad, atwo-course (cotton-groundnuts). Watering isevery 2 weeks, and a light watering is given7 days before harvest to facilitate pulling ofgroundnuts as the soils are heavy clay. Tenantsnormally delay harvest and this causes losses ofpods in the soil. In most areas, weeding iscarried out by hand, while some governmentschemes use herbicides.Past Research AchievementsA g r o n o m yDisc plowing six inches deep, two passes ofdisc harrow, or rotovation, followed by levellingand ridging has increased pod yield substantially(Ishag et al. 1980). A single plant at 7.5 cmspacing between plants has resulted in higheryields (Tahir and Misovic 1967). Ishag (1970)found that 15 cm between plants and two seedsper hole significantly outyielded 30 cm spacing.Planting unshelled pods usually results in lowyields mainly because of a sparse plant populationstand. High pod yield is achieved from earlyJune planting (Ishag 1965). The average seedingrate in irrigated areas is about 30 kg (shelled282

asis). Recent work (Ishag et al. 1980) showed amarked responseto phosphorus when suppliedwith the seeds.G r o u n d n u t B r e a d i n gGroundnut improvement by selection in Sudanstarted with the screening of the Tozi collectionassembled by A. H. Bunting (1954-55). Tahir(1965) made a few crosses in 1949. The line MH383, introduced from Nigeria but originallydeveloped in India, was selected for productionin the irrigated Vertisols of central Sudan (ElAhmadi 1965-66, 1969-70 and Nur 1976).Recently, breeding has received more attentionand a full time breeder is now in charge of aprogram aimed at the development of highyielding, early maturing, spreading bunch typesadapted to the irrigated Vertisols; selection ofearly maturing, drought tolerant cultivars forthe rainfed sandy soils of western Sudan; selectionof large seeded Virginia types for productionin northern Sudan; development ofgenotypes with increased resistance to infectionby Aspergillus flavus and aflatoxin production;and development of genotypes with highoil content and high kernel yield.Hybridization work started in 1978. Breedingmaterial is being assembled from the UnitedStates and ICRISAT, and close contact with theICRISAT program will be maintained.P e s t s a n d DiseasesInterest in pests and diseases of groundnuts inthe Sudan started in the late sixties when thecrop was introduced into the rotation of theGezira agricultural scheme. The following informationhas been obtained from old recordsand recent surveys and research:Bird, Insect and Rat PestsAccording to Ahmed and El Amin (1976), crowsCorvus a/bus (Mull.) and doves (Streptopeliadecipiens) may inflict some damage duringJune and July by picking up unburied or badlyburied seeds. This loss usually ends by the firstirrigation or rain.Millipedes (Julidae) appear in great numbersat the beginning of rains and they chop thetender parts of the crop at night. During the day,millipedes hide under the shade of trees, loosebarks, and in soil cracks and depressions.Termites (Microtermes thoracalis) (S. jost),Macrotermes bellicosus (Smeath) and M.natulenses (Hak.) cause sporadic damage.The chaffer grub (Schizomycha cibrat) feedson the subterranean parts of the plant. Sometimesthe embedded larvae of an unidentifiedyellow grub may feed on the inside tissue of thestem and cause wilt.Thrips, Caliothrips impurus (Pr.) and Caliothripssudanensis (Bagn and Cam), usually appearin large numbers in mid August but rarelyget serious. Aphids {Aphis craccivora) usuallyattack late sown groundnuts in irrigated areas.The following minor pests many of whichwere noted by Clinton (1960) and Ali et al. (1970)in rainfed areas, have been found ongroundnuts:Egyptian leaf worm (Spodoptera littoralis)(Boist); leaf roller, Cosmophila flava (F);whitefly (Bemesia tabaci) (Genn); green bug(Nezara viridula (L); stainer bug (Dysdercusspp); American bollworm, Heliothis armigera(Hb); and grasshoppers (Ailopus spp andCatantops spp.).Field rats (Mastomys natolensis macrelepsis(Sund)) occasionally attack seeds before germination.DiseasesAt present there are no serious diseases ingroundnuts, yet the following diseases wererecorded in different parts of the Sudan by Tar(1955), Ali et. al (1970), El Nur and Ibrahim(1970) and Khalifa (1973):Cercospora arachidicola (Hori) (early leafspot) and Cercosporidium personatum (Berkand Curt) (late leaf spot) occur late in the seasonand according to Khalifa (1973) they do notreduce yield significantly.Rust, Puccinia arachidis (Speg), was first recordedby Ali (1978) in both rainfed and irrigatedcrops in the Sudan. It occurs very late inthe season and its effect on yield is not yetassessed.Crown rot caused by Aspergillus niger (VanTieghem), Phyllosticta sp causing leaf spots,and the rosette disease were recorded by Tar(1955) in the early fifties.A leafmottle caused by a virus disease hasbeen recorded in some parts of the country byHashim (1975).283

Very sporadic wilts have been noted in somefields and the f o l l o w i n g pathogens were isolated(Ali 1980) f r o m w i l t i n g p l a n t s : Macrophominas p ; Fusarium s p p ; Rhizoctoniasolani (Kuhn); and a septate nonspore-formingfungus w i t h a fluffy mycelium.Aspergillus flavus was isolated f r o m a fewbroken seeds after harvest in the Gezirascheme. A little incidence of aflatoxin, far belowthe internationally accepted level, was detectedin these seeds (El Nur et al. 1970).W e e d sMany grasses and broadleaved weeds werefound to compete w i t h groundnut in its earlygrowth stages. According to Ishag (1971) andHamdoun (1976), yield could be reduced by7 3 - 8 0 % if thefirst weeding were delayed morethan 4 weeks after planting.ReferencesAHMED, K. M., and E L A M I N , T. M. 1976. Minutes of theInternational Symposium on Field Pests ofGroundnuts and Millet. The African GroundnutCouncil, 11 Ahmado Bello Road, Victoria, Island,Lagos, Nigeria.ALI, M. A. 1978. Groundnut rust in the Sudan. A shortpaper submitted to the technical committee of theAgricultural Research Corporation. No.I.M.I.233179, Kew, England.A L I , M. A. 1980. Personal communication.An, M . A . , A G E E B , 0 . A. A.,OMER,H.A.,andAGABENi,A.G. 1970. Report of the Kordofan Agricultural Surveyand Investigation Team. Agricultural Research Corporation,Sudan.BUNTING, A. H. 1954-55. Report of the Tozi ResearchStation, Sudan.CLINTON, P. K. S. 1960. Seedbed pathogens ofgroundnuts in the Sudan and an attempt at controlwith an artificial test. Empire Journal of ExperimentalAgriculture. 28: 211-222.EL NUR, E. and IBRAHIM, G. 1970. Aspergillus flavusand aflatoxin production. Sudan AgriculturalJournal 5: 61.EL AHMADI, A. B. 1965-66. Annual Report of the SennarResearch Station, Agricultural Research Corporation,Sudan.ELAHMADI, A. B. 1969-70. Annual Report of the SennarResearch Station, Agricultural Research Corporation,Sudan.HASHIM, A. 1974-75. Annual Report of the Gezira ResearchStation, Agricultural Research Corporation,Sudan.HAMDOUN, A. M. 1976. Chemical weed control ingroundnuts in the Kenana area of the Sudan. ExperimentalAgriculture 12: 113-119.ISHAG, H. M. 1965. The effects of sowing dateon growth and yield of groundnuts in the Gezira.African Soils 10: 509-520.ISHAG, H. M. 1970. Growth and yield of irrigatedgroundnuts {Arachis hypogaea L.) at different spacingin the Sudan Gezira. I. Flowering & yield components.Journal of Agricultural Science 74: 533-537.ISHAG, H. M. 1971. Weed control in irrigatedgroundnuts {Arachis hypogaea L). in the SudanGezira. Journal of Agricultural Science, Cambridge77: 237-242.ISHAG, H. M., SAID, M. B., KAROURI, A. 0., and SEIFELDIN, E. 1980. Effects of land preparation, spacing andphosphorus application on yield of irrigatedgroundnuts {Arachis hypogaea L.) Journal of AgriculturalScience, Cambridge (in press).KHALIFA, 0. 1972-73. Annual Report of the KenanaResearch Station, Sudan.NUR, I. M. 1976. A new groundnut variety MH.383 forirrigated areas of Sudan. East African Agriculturaland Forestry Journal 41: 294-297.SAID, M.B.,and MUSTAFA, M. A. 1978. Problemsof soilproductivity under arid and semi-arid conditions ofthe Sudan. Workshop on maximizing soil productivityunder arid and semi-arid conditions. Oct 23-26,Alexandria, Egypt.TAHIR, W. M. 1965. Groundnut improvement in theSudan. Experimental Agriculture 1: 225-235.TAHIR, W. M., and Misovic, M. S. 1967. Agronomicfactors influencing yield and quality of groundnutsin the Sudan Gezira. Experimental Agriculture3: 41-53.TAR, S. A. J. 1955. The fungi and plant diseases of theSudan. Published by the Commonwealth MycologicalInstitute, Kew, Surrey, England.284

Groundnut Production, Utilization, ResearchProblems and Further Research Needs in TanzaniaA. Bolton*ProductionThere is a shortage of edible oil in Tanzania duelargely to increased domestic consumption andto some extent to increased emphasis on foodcrops and cash crops. An Oilseeds ResearchProject was started in 1978 with cooperationfrom the British Government Overseas DevelopmentAdministration. It was based in thesouth of the country but with national responsibilitiesto deal with sesame, sunflower andgroundnut which are the main annual oilseedcrops.The area under annual oilseed crops(groundnut, sesame, sunflower, castor) isdifficult to estimate, but the Ministry of Agricultureestimates give a total of about 150 000 hectaresof which groundnut accounts for about100 000 ha. Reliable yield figures are not obtainablebut good groundnut farmers may produceabout 700 kg/ha with the traditional peasantfarmers getting half of this or less.Mixed cropping is prevalent and groundnutsare nearly always grown in association withother crops. There may be several crops all onthe piece of land with more or less randomplanting of groundnut with cereals (maize orsorghum) etc. It is rare to find fertilizer applied.Official marketing is carried out by GAPEX(General Agricultural Products for Export) andthe proportion of the crop marketed through theorganization, as shown in Table 1, is only afraction of total production. There is considerabledomestic consumption by the subsistencefarmer, and most of the surplus is sold throughunofficial channels at a price well above theofficial price offered by GAPEX.The oil mills in Tanzania have a potential demandfor 4000 tonnes of groundnut annually* Agricultural Research Institute, Nallendele, P.O.Box 509, Mtwara, Tanzania.(out of a total requirement for all oilseed cropsof over 200 0001) but supplies are considerablybelow this figure, although if the estimate of100 000 ha under groundnut is anywhere nearreliable, the quantity needed by the mills is stillonly a small fraction of thetotal production. Theprice offered by GAPEX is at present Shs.4.00/kg(approximately Rs 4) but the unofficial price canbe several times higher, particularly in the largeurban centers.ResearchA good deal of work has been carried out in thepast in Tanzania especially in the years immediatelyafter the second world war when theBritish Government started a large scale productionscheme based at several centers in thecountry. This scheme was not successful. Sincethen, work has included a number of varietytrials run within the network of research stationsadministered by the Crop Research Divisionof the Ministry of Agriculture. Between the1969- and 74-75 seasons, 28 trials tested 118entries but the trials were not coordinated andjoint analysis has proved impossible.Many of these entries were collections oflocal material largely from the north-west areaof Tanzania collected by Ukiriguru. The exactorigin is not always clear, but they are classifiedmainly as upright bunch with a fewdescribed asspreading, although none appear to be ofpurely Virginia or runner habit. In the cropsgrown by local farmers in the south, a smallnumber of plants of runner habit may be foundin the crop.The Oilseeds Research Project which startedin 1978, aimed primarily at breeding and theagronomy of sesame and sunflower. However,in view of the importance of groundnut to thepeasant farmer, groundnuts were includedwith the intention of sorting out the varietal285

position as far as possible, and of conductingagronomic experiments with the more promisingentries. Standard varieties in the collectionincluded Natal Common, Sigaro Pink, RedMwitunde and Makulu Red but the purity ofthese named entries and of those in the localcollection is so doubtful that no single namedvariety in the country prior to 1978 can be acceptedas entirely valid.During the past two seasons, samples ofsome named varieties and of breeding materialhave been received from other countries includingthe United States and India (ICRISAT), togetherwith some local types from the Lindi andMtwara Regions in the south of Tanzania. Atpresent they areundergoing multiplication andwill be tested in trials as sufficient stocks of seedbecome available.Results of yield trials carried out at four sitesin 1978-79 are presented in Table 2. Entriesidentified by numbers are those from theUkiriguru collection and the indications are thatTable 1.Marketed groundnut production In Tanzania.Marketed production(tonnes) Exports (tonnes) Mtwara Dodoma TaboraRegionRegionRegionYear Total a Groundnut Total a Groundnut(%)(%)(%)71-72 30 598 3295 27 686 7572-73 30 497 3454 20 733 232 38 35 2273-74 19 874 1363 9 265 Nil 29 7 4674-75 16 733 509 9 702 Nil 48 - 575-76 15 489 510 2 259 Nil 55 5 -76-77 14 157 417 3 000 Nil 50 14 -77-78 17 437 1448 6 669 Nil 61 23 -78-79 b 22 787 2615 _ — 52 b 2 b 16*a. Total Is figure for sesame, castor, sunflower, and groundnut.b. Purchases to April 1979.Table 2.Groundnut variety trials 1 9 7 8 - 7 9 ; kernel yield (kg/ha).Variety Nachingwea Naliendele Suluti Mtopwa Mean69.62.2.5 1538 1516 1169 1146 134270.1.1.1. 1468 1710 1215 955 133769.63.2.5 1577 1463 1271 1028 133569.17.6 1633 1610 1218 792 131369.358.1.4 a 1596 1450 1208 863 127969.29.2 1535 1613 1124 839 127869.15.3 1605 1320 1204 756 1221Natal Common 1227 1315 1277 1007 120769.99.1.2.4 1237 1473 1069 940 118070.7.3. 1387 1331 1208 748 116969.17.1 1345 1505 960 850 1165Sigaro PinK 1122 623 874 471 773Mean 1439 1411 1150 866 1217S.E. 1019 102.0 106.9 116.7 54a. 68.35a. 1.4 Is Natal Common ex. Ukiriguru.286

adequate yields can be obtained under reasonableconditions.Tables 3 and 4 give results from last seasontesting at six sites which were much the same asentries in the previous season. The main conclusionis that groundnut can be successfullygrown over a fairly wide range of climatic conditions.Next season, 1980-81, some introductionswill be tested extensively.Yields of some introductions are encouraging,e.g., Tifspan did well in a multiplication plotlast season. It is hoped to run trials at up to 20sites to arrive at reliable performance data.A few agronomy trials were carried out lastseason. One plant population trial (Table 5) indicatedthat populations of up to 250 000 plantsper hectare gave increasi ngly higher yields. Thedifficulty is the large amount of seed requiredfor planting which the peasant farmer does nothave available. The variety used last seasonwas one of the local entries.A similar trial in the 1978-79 season usingSigaro Pink showed that spacing between rowsof 60 cm is probably too wide. The present recommendationsfor crops in southern Tanzaniais 50 cm x 10 cm giving 200 000 plants per hectare.A start was made on intercropping trials withresults as in Tables 6 and 7. The aim was tocompare rows of cereal, maize or sorghum interspersedwith 1, 2, or 3 rows of groundnut.Last season was exceptionally difficult with apronounced drought for 4 weeks from about 2weeks after planting. The yields obtained aretherefore not unsatisfactory. There was adefinite advantage from the intercropping systemat one site (Naliendele) but not at the other(Nachingwea). Spacing of sorghum andTable 4.Groundnut variety trials 1980; kernelyield (kg/ha).Variety Nachingwea Naliendele Mean69.63.2.5. 2228 1502 186569.1.5 2114 1331 172369.29.2 1922 1463 169369.99.2.4 2070 1270 167069.17.6 1798 1525 166269.62.2.1. 1782 1516 1649Natal Common 1808 1422 161569.62.2.5 1742 1429 158670.1.1.1. 1968 1196 158269.17.2 1772 1301 153769.15.3 1854 1218 153669.35a. 1.4. 1650 1356 1503Local 2198 404 130169.35.1. 1136 1234 1185Sigaro pink 1388 576 982Red Mwitunde 1160 439 800Mean 1787 1199 1493S.E. 131.4 67.6Table 3.Groundnut variety trials 1 9 7 9 - 8 0 ; karnal yield (kg/ha).Variety Ndengo Suluti Utengule Mtopwa Mean69.62.2.5. 903 798 808 1600 102769.15.3 1005 584 967 1520 101970.1.1.1. 1190 514 696 1600 100069.99.1.2.4 935 770 879 1300 97169.29.2 855 818 866 1140 92069.63.2.5 880 484 788 1460 903Natal Common 1013 790 861 - 88869.35a. 1.4 827 588 467 1560 86169.17.6. 834 610 867 1120 858Local - 280 409 - 345Mean 938 624 761 1412S.E. 76.6 71.6 94.8 -Note: Last two replications of the Mtopwa trial were not enalyzed. Data presented above Indicate yield levels attainable.Naliendele and Nachingwea results are shown in Table 4.287

groundnut was 50 cm x 10 cm and of maize,50 cm x 50 cm. These agronomy trials will becontinued next year.Table 8. Groundnut plant populations,Naliendele, 1979-80.TreatmentSpacing (cm) Plants/ha (kg/ha)1 60 x 40 41667 11384 40 x 40 62 500 12332 60 x 20 83 333 12765 40 x 20 125 000 14753 60 x 10 166 667 14206 40 x 10 250 000 1783S.E. 53.1Pests and DiseasesNo specific research work was conducted andthe following brief notes are records from themain center, Naliendele.Insects ObservedGROUNDNUT APHID (APHIS CRACCIVORA). Thesewere observed giving rise to rosette virus butnot in large numbers. The number of plantsaffected was small. The disease has been reportedoften in Tanzania but the true effect ofthe virus on the crop is not known with anycertainty.BEAN WEBWORM (LAMPROSEMA INDICA). Atle damage was caused.SPOTTED BORER (MARUCA TESTULAUS).lit-TheseTabla 6. Intareropping groundnut/maize, Nachingwaa, 1979-80.Crop valueTreatment LER (Sh./ha)Maize pure 4269Groundnut pure 6469Intercropped maize/groundnut 1:1 1.24 6760Intercropped " " 1:2 0.87 5104Intercropped " " 1:3 1.04 6075S.E. 0.110 546Mean yield pure stand maizegroundnut4270 kg/ha1617 kg/haTabla 7. Intercropping groundnut/sorghum, Naliendele, 1979-80.TreatmentSorghum pureGroundnut pureintercropped sorghum/groundnut 1:1Intercropped " " 2:2Intercropped " " 1:3S.E.Mean yield pure stand sorghumgroundnutLER1.781.811.940.1001893 kg/ha639 kg/haCrop value(Sh./ha)18932566380037504335320.9288

were present in considerable numbers duringthe two seasons.AMERICAN BOLLWORM WEUOTHIS ARMIGERA).Considerable numbers of these caterpillarswere found feeding on the leaves and in1980 there was noticeable damage after flowering.They were also present on sunflower headsand sorghum in adjacent plots.COTTON LEAFWORM (SPODOPTERA UTTORAUS).Small numbers of the caterpillars were foundfeeding on the leaves.TOBACCO WHITEFLY (BEMISIA TABACI). This wasoccasionally found in small numbers suckingthe underside of groundnut leaves.GROUNDNUT HOPPER (HILDA PATRUELIS). Afew scattered plants were attacked by this insectwhose nymphs and adults suck from the base ofthe plant under the soil surface. Attacked plantswilted and died.LEAF BEETLE (CYPONYCHUS SPP). Some adultbeetles were found eating from the leaf surfaceleaving irregular patterns on the leaves.FLOWER (POLLEN) BEETLES (MYLABRIS SPP ANDCORYNA SPP). These beetles were common onthe groundnut flowers in both seasons.TERMITES. Nearly always found somewhere.Diseases ObservedANGULAR LEAF SPOT {CERCOSPORA PERSONATAAND C. ARACWDICOLA). This disease wascommon in plants which had nearly completedflowering. It was therefore not so serious as tocall for control measures.RAPID YELLOWING OF WHOLE PLANT. In the1980 crop, there was a severe yellowing ofplants in most plots around the Institute (but notin the experimental field) and on experimentalplants at one subcenter.The following fungus species were identifiedfrom root and stem selections: Curvularialunata; Fusarium spp; and Botryodiplodiatheobromae.Root and stem sections showed brown discolorationon the conducting tissues. The podswere also infected.289

Groundnut Production, Utilization, ResearchProblems and Further Research Needsin ZimbabweG. L. Hildebrand*Zimbabwe is situated between 16° and 22°Slatitude and varies in altitude from 160 m to2000 m. Zimbabwe is part of the plateau whichtraverses the subcontinent of Africa. This centralplateau, known as the Highveld extends forsome 650 km in a south-west to north-eastdirection. The rainfall is generally adequate tosupport a broadly based agricultural industryand the bulk of the country's development isconcentrated in this area.On either side of the central plateau lies theMiddleveld where altitudes range from 600 to1200 m. Below 600 m lies the Lowveld wherehot and generally drier conditions prevail. Themain cropping area lies between 300-1600 m,although cropping is largely dependent on irrigationbelow 800 m.The climate is characterized by definite wetand dry seasons, with the wet season beginningin November and ending in late March. Someclimatic data for selected sites at a range ofaltitudes in Zimbabwe are given in Table 1.ProductionThe groundnut crop is small by world standardsbut is an important source of food in the ruralarea and surpluses are an important cashearner.No accurate production figures are availablebut estimates and sales for the 1978-79 and1979-80 seasons are given in Table 2. Thesefigures show that more than 90% of groundnutproduction comes from the rural areas and thatthis sector retains about 90% of its productionfor local use. Groundnuts are a controlled pro-• Groundnut Breeder, Crop Breeding Institute, Departmentof Research and Specialist Services, P.O.Box 8100, Causeway, Zimbabwe.duct in Zimbabwe and must be sold through theGrain Marketing Board or its agents.Estimated deliveries to the Board have beenof the order of 15 000 to 20 000 tonnes annuallyin recent years. Before the war in Zimbabweannual deliveries were about 30 000 tonnesandhave now reached 44 000 tonnes.The irrigated crop that consists of long seasonvarieties grown in the large scale farmingarea, yields about 50% confectionery nuts ofwhich about 75% are exported. The smallkernelledshort season varieties (Spanish andValencia types), that are grown under drylandconditions in the rural areas, yield about 25%confectionery nuts of which about 60% are exported.Crusher grade accounts for 65% of thedryland crop while about 10% is used for seed.With peace returningtothecountry, and withit, improved availability of inputs, better communicationsand transport, and easier marketing,it is estimated that annual deliveries arelikely to increase to about 30 000 tonnes in thenear future.A large increase in area planted is unlikely tocome about in the foreseeable future and thereforeit is doubtful whether further increases indeliveries will occur unless there are significantincreases in yield.Varieties and Production MethodsThere are two main types of varieties grown. Thelong season varieties (mainly of Virginia botanicaltype), depending on altitude, mature in140-200 days and are generally only suited toproduction under irrigation where planting canbe carried out before the onset of the rains.These varieties are planted from late-September to mid-October and are harvestedfrom late-March to mid-April. The ability to plantearly with irrigation has resulted in theachievement of high yields (Metelerkamp290

1967). The highest yield achieved to date on afield scale is 9.6 t/ha unshelled.The short season varieties (Spanish andValencia botanical types), depending onaltitude, mature in 110-150 days and are usuallygrown under rainfed conditions but haveproduced promising yields when grown underirrigation in the warmer areas.Table 1.Some climatic data f o r selected sites in Zimbabwe (means f o r 5-month periodNovember—March).Meteorological station (with altitude in m)Marandellas Gatooma Tuli Triangle1628 1157 765 421Mean max. temperature (°C) 24.4 28.4 30.4 32.2Mean min. temperature (°C) 14.2 17.0 17.9 19.3Mean hours sunshine/day 6.5 6.8 7.3 7.3Mean evaporation/month (mm) 152 175 198 200Duration of rainy season (days) 135 125 80 105Rainfall for Nov-Mar (mm) 840 706 394 539Annual rainfall rail (mm) 936 776 455 622Table 2.Groundnut production in Zimbabwe (unshelled groundnuts; Crop Forecast Committeeestimates).SeasonSourceAreaplanted Yield Production Retention Deliveries(ha) (t/ha) (tonnes) (tonnes) (tonnes)1978/79 Large-scale farming areas- irrigated- dryland1 50014003.331.435 0002 0002 900 7 000 250 6 7501978/79Small-scale farming areasRural areas12 000240 0000.580.427 000100 0002 00091 7505 0008 250252 000 107 000 93 750 13 250Total 254 900 114 000 94 000 20 0001979/80 Large-scale farming areas- irrigated- dryland2 20014003.501.647 7002 3003 600 10 000 300 9 7001979/80Small-scale farming areasRural areas11 000360 0000.540.316 000110 0005 000100 70010009 300371 000116 00010570010 300Total 374 600 126 000 106 000 20 000291

Although good yields have been achieved byefficient producers the national average yieldsare disappointingly low.In recent years a close relationship betweenweather and yield has become evident (Williams,Hildebrand and Tattersfield 1978). Theinfluence of radiation and temperature on finalyield is illustrated in Figure 1 for two shortseason varieties grown in variety trials at SalisburyResearch Station over a period of 12 years.An interaction with environment has alsobecome evident in which Valencia varietiestend to yield more in the cooler, high altitudeareas while the Spanish types tend to yieldmore than Valencia types in the warmer andgenerally drier areas.The influence of altitude, and therefore temperature,on the mean yields and gross returns ofthese two varieties at 11 sites over a number ofyears is illustrated in Figures 2 and 3.Some work on the agronomic aspects ofgroundnut production was conducted in thesixties and early seventies and has resulted inthe basis for recommendations for productionin the large scale farming area (Collett 1973).These have also provided principles on which tobase recommendations for production in therural areas. However, certain problems stillexist which are limiting yields and for whichsolutions must be sought. These are dealt within more detail in the section under FurtherResearch Needs.Variety ImprovementLong-Season VarietiesBreeding and selection continues to developResearchThe bulk of the research effort in the pastdecade has been placed on variety improvement(Hildebrand 1975a), physiology andgrowth analysis. This effort has resulted in anumber of varieties being made available forcommercial production (Department of Researchand Specialist Services 1979) and a verysignificant contribution has been made to theunderstanding of groundnut growth undervarying climatic conditions.Figure 2.Altitude (m)The relation between yield and altitudefor two groundnut varieties.Radiation (22-41 days) + Mean maximum temp. (°C)(December + February + M8rch)Figure 1.The relation between yield andweather for two groundnut varietiesgrown at Salisbury Research Station.Figure 3.The relation between gross returnand altitude for two groundnut varieties.292

improved varieties for production under irrigation.Table 1 shows that the irrigated crop,that is largely grown in the large scale farmingarea, is small but it is nevertheless importantas the high yields and good quality nuts producedare a valuable earner of foreign exchangewhen exported for confectionery. Objectivesare to improve yield potential, kernel size andkernel quality. Considerable emphasis has beenplaced on selection of varieties with a pale pinktesta since world markets for red-skinned varietiesare limited. This had led to the developmentof the variety Egret which is now the mainvariety grown (Hildebrand 1975c). Selection willcontinue for higher yields, better quality andimproved agronomic aspects such as diseaseand pest resistance, strong peg attachment andacceptable shelling characteristics (Hildebrandand Smartt 1980).Short-Season VarietiesHIGH ALTITUDE AREAS. Many of the Valenciatypes collected in the country and introducedfrom elsewhere are red-skinned. Because of thelimited market for red-skinned groundnuts in theconfectionery trade, considerable emphasishas been placed on the selection of pinkskinnedValencia varieties or varieties with acceptabletesta color that yield well in the highaltitude areas.The red-skinned Valencia R2 was released in1974 (Department of Research and SpecialistServices 1974). This variety was introducedfrom Dr. W. C. Gregory's South American collectionand has given high yields and showssome tolerance to Cercospora arachidicola. Anumber of promising pink Valencias and othervarieties which are adapted to the higher altitudeareas are in advanced stages of varietytesting at this time. Promising results have beenshown by locally bred varieties, some arisingfrom infraspecific crosses.The past season's results indicate toleranceto drought, improved kernel size and qualityand the presence of seed dormancy in some ofthe locally bred selections.Low ALTITUDE AREAS. Natal Common hasbeen grown in these areas for many years. It is asmall-kemelled Spanish variety with a light pinktesta. Considerable effort in the past decade hasbeen placed on the selection of similar varietieswith improved yield, kernel size and kernelquality. It was felt that under conditions oflimited rainfall, it will be difficult to make significantincreases in yield but that superiorkernel size and quality could result in greaterreturns to the producer through better gradesand greater value in the confectionery market.A Spanish type, Jacana, having superioryield, kernel size and market quality, was releasedin 1975 (Hildebrand 1975b). This varietyhas, however, recently been withdrawn becauseof difficulties experienced in shelling.A number of varieties in advanced stage oftesting have shown promise including somealready mentioned from locally bred selectionswhich appear to be adapted to a wide range ofaltitudes.Dwarf GenotypesExtreme rank growth has been experiencedwith long and short season varieties whengrown at low altitudes under irrigation.Branches often reach 1.5 m or more in lengthand represent an apparent waste of photosynthatein producing excess vegetativegrowth.Selection for genotypes with short staturehas led to encouraging results with lines whichhave stems of only 0.5-0.8 m in length.Disease ResistanceSources of tolerance to Phoma arachidicolahave been included in crosses and selectionfrom segregating populations and progenies iscurrently being undertaken.Some breeding and screening for rust resistancehas been carried out. Three of the FESR Falines were used as parents in crosses but nomajor emphasis has been placed on this workas serious rust occurs only in the low altitudeareas. It is not likely to become as economicallyimportant as the leaf spot diseases.One source of tolerance to Cercosporaarachidicola has been used in some crosses.Some fairly promising selections from a crossbetween this Valencia line and a long seasonline are in variety trials.Shelling AbilityThe marketing policy in Zimbabwe is to encour-293

age delivery of unshelled pods for centralizedshelling by the Grain Marketing Board. There isa specific requirement therefore for varietiesthat can be suitably shelled since although asmall proportion of the crop is marketed, thatportion is however valuable, and it must bepossible to carry out efficient shelling.Jacana is one variety which shells very poorlywhen grown under difficult conditions of harvestingand curing. For this reason routinescreening of shelling ability of all varietiesentered into variety trials is now carried outusing a Dawson Model 3 groundnut shelter(Davidson and Mcintosh 1973). Considerabledifferences have been noted between varietiesbut the poor shelling results of Jacana underfield scale production has not been found inJacana grown in variety trials.D i s e a s e C o n t r o lResearch on the epidemiology of leaf spot andpod rot fungi has been carried out over the pastdecade (Cole). Leaf spots caused by Cercosporaarachidicola and Cercosporidium personatumare well controlled by the recommendedmancozeb/benomyl mixture. Good control hasalso been achieved with chlorothalonil. Phomaarachidicola is more difficult to control withchemicals. It has been found that C. arachidicolais antagonistic toward P. arachidicola and completechemical control of C. arachidicola resultsin severe infection by P. arachidicola.Delaying the start of a chemical disease controlprogram, to allow a low level of C.arachidicola to develop, generally results in alow and balanced level of both pathogens.Efficient control of foliar diseases results inreduced losses caused by pod rots and podshedding.Depressed yields due to chemical diseasecontrol have been experienced under conditionsof limiting moisture. For this reason sprayingof dryland crops is generally not recommended.Encouraging results have been achievedusing spinning disc ULV sprayers and thesecould be of considerable benefit on irrigationschemes in the rural areas.Aspergillus flavus appears to occur in significantlevels only in those years where amidseason dry spell is experienced duringJanuary or February.Rosette virus is of economic importance only inthe rural areas when plant stands are thin.P h y s i o l o g y a n d G r o w t h A n a l y s i sA very significant contribution has been madeto the understanding of groundnut growth inthe past decade (Williams, Wilson and Bate1976; Williams 1979a, b, c, d, e). This has shownhow groundnuts respond to the environmentand how different varieties are affected bydifferences in climate (Williams, Wilson andBate 1975; Williams and Allison 1978).A g r o n o m yResearch on plant populations, spacing,and early planting with irrigation have madesignificant contributions to increased production(Metelerkamp 1967). In additon the work onphysiology and growth has contributed towardsbetter agronomic practice, particularly inthe irrigated crop.M e c h a n i z a t i o nInvestigation into mechanization of groundnutproduction has resulted in expansion ofmechanized harvesting and curing of the irrigatedcrop plus development of picking andcleaning aids for small scale producers. Investigationsinto drying methods, including the use ofsolar energy, have been conducted (Oliver1978).W e e d C o n t r o lScreening of chemicals for, and methods of,weed control have continued and have resultedin chemical weed control recommendationswhich are widely used in the irrigated crop(Borland 1973 and 1975).A f l a t o x i nDuring the sixties and early seventies, a surveyof the incidence of aflatoxin in the national cropwas conducted. This work led to the establishmentof a monitoring procedure for aflatoxin foruse by the Grain Marketing Board (Du Toit 1971)and established the environmental conditionswhich would influence the incidence of Aspergillusflavus damage in the national crop.294

N u t r i t i o nLimited research on nutrition of groundnuts onpoor soils in the rural areas has shown largeresponses to the application of manure, manureand gypsum, and phosphates. Application ofphosphate and sulphur are most important. Thefertilizer recommend ations as made by fertilizeradvisory services for large scale farming areasdo not apply since the residual fertility in therural areas is very low. It is felt that groundnutscould play an important part in the improvementof general fertility practices in the ruralareas since large applications of nitrogen arenot required and the good monetary returnsfrom the groundnut crop are likely to betterstand the cost of increased fertilizer applicationthan many other crops.Responses to Rhizobium inoculation havebeen small since there are naturally occurringRhizobia in most soils.A g r o n o m yIt is generally accepted that the technology forincreased groundnut production is available.The greatest need now is for an expansion ofthe extension effort.There are, however, certain problem areas theextent of which are not known and it is felt thatthese should be investigated as early as possible.These problem areas include: (1) methodsof facilitating earlier planting. Lack of draught isthe greatest limiting factor to being able toplow and plant as early as possible after thefirst rains. Although it may not facilitate earlyplowing, water-planting ahead of the rainsmay enable the producer to best use residualmoisture and favorable early season radiationand temperature; (2) the effect of nematodes ongroundnut crops is not well known. Some effortshould be made to establish if it is in fact aproblem.Further Research NeedsV a r i e t y I m p r o v e m e n tThis must be continued and expanded with theobjective of developing new varieties, particularlyfor the rural areas, which have: improvedyield and quality; drought tolerance; diseaseand pest resistance; seed dormancy at harvest;reduced vegetative growth for those areaswhere rank growth occurs; and satisfactoryshelling quality when grown under difficult harvestingand curing conditions.Disease C o n t r o lResearch should continue with regard to:epidemiology of the economically importantdiseases; screening of chemical control measures;cost and efficiency of chemical controlmethods; and feasibility of foliar disease controlin the dryland crop.P e s t C o n t r o lHilda patruelis has been a problem in the past inthe large scale farming area, particularly in dryseasons. It could well be a problem in the ruralareas. Further research on the biology andcontrol of this pest is necessary.N u t r i t i o nFurther research is needed to provideguidelines for fertilizer applications in the ruralareas with particular reference to: basal fertilizerrecommendations; the timing of gypsumapplications since it is likely that gypsum will bea more important source of sulphur than calcium;and levels of starter nitrogen requiredand whether benefits would accrue from theuse of Rhizobium inoculant since groundnut inthe rural areas are not, as a rule, inoculated.R e f e r e n c e sBORLAND, T. M. 1973. Weed control systems forgroundnut and soyabeans. Rhodesia AgriculturalJournal 70: 162.BORLAND, T. M. 1975. Weed control in oilseed crops.Rhodesian Farmer 46: 15, 25.COLE, D. L. Diseases of groundnuts (Arachis hypogaeaL.) 1. Fungicide spray effects on Cercosporaarachidicola and Phoma arachidicola leaf infection,kernel yield and pod rots. (Submitted for publicationin Zimbabwe Journal of Agricultural Research).COLLETT, W. E. 1973. Oilseeds Handbook. Departmentof Conservation and Extension, Salisbury, Zimbabwe.295

DAVIDSON, J. I. and MCINTOSH, F. P. 1973. Developmentof a small laboratory shelter for determining peanutmilling quality. Proceedings of the American PeanutResearch Education Association 5(1).DEPARTMENT OF RESEARCH AND SPECIALIST SERVICES.1974. Release of Valencia R2 groundnut. RhodesiaAgricultural Journal 71: 129.DEPARTMENT OF RESEARCH AND SPECIALIST SERVICES.1979. A description of crop varieties released by theDepartment of Research and Specialist Services.Supplement to Zimbabwe Rhodesia AgriculturalJournal 76, 1979.DOTOIT, A. A. 1971. Safety standards for aflatoxins inRhodesia. Rhodesia Agricultural Journal 68: 67.HILDEBRAND, G. L. 1975a. Groundnut variety improvementin Rhodesia. Workshop on germplasmpreservation and genotype evaluation in peanuts.July 12-15,1975. University of Florida, Gainesville,Florida, USA.HILDEBRAND, G. L. 1975b. Jacana groundnut — cropvariety release notice. Rhodesia Agricultural Journal72: 153.HILDEBRAND, G. L. 1975c. Egret groundnut — crop varietyrelease notice. Rhodesia Agricultural Journal72: 154.HILDEBRAND, G. L, and SMARTT, J. 1980. The utilizationof Bolivian groundnut (Arachis hypogaea L.)germpiasm in Central Africa. Zimbabwe Journal ofAgricultural Research 18: 39.M ETERLERKAMP, H. R. A. 1967. Response to early plantingand irrigation of a late maturing groundnut variety.Rhodesia Agricultural Journal 64: 127.OLIVER, G. J. 1978. Report of oilseeds mechanizationinvestigation. Institute of Agricultural Engineering,Department of Conservation and Extension, Salisbury,Zimbabwe.WILLIAMS, J. H. 1979a. The influence of shading duringthe pre-flowering phase of groundnuts {Arachishypogaea L.) on subsequent growth and development.Rhodesia Journal of Agricultural Research17: 31WILLIAMS, J. H. 1979b. The physiology of groundnuts(Arachis hypogaea L. cv. Egret). 1. General growthand development. Rhodesia Journal of AgriculturalResearch 17: 41.WILLIAMS, J. H. 1979c. The physiology of groundnuts{Arachishypogaea L. cv Egret). 2. Nitrogen accumulationand distribution. Rhodesia Journal of AgriculturalResearch 17: 49.WILLIAMS, J. H. 1979d. The physiology of groundnuts{Arachis hypogaea L. cv Egret). 3. The effect of thinningat different stages of development on reproductivegrowth and development. Rhodesia Journalof Agricultural Research 17: 57.WILLIAMS, J. H. 1979e. The physiology of groundnuts{Arachis hypogaea L. cv. Egret). 4. The growth ofgroundnut fruit set at the start and end of pod setting.Rhodesia Journal of Agricultural Research17: 63.WILLIAMS, J. H., and ALLISON, J. C. S. 1978. Geneticdifferences in the growth of groundnuts {Arachishypogaea L.) pods and kernels. Rhodesia Journal ofAgricultural Research 16: 73.WILLIAMS, J. H., WILSON, J. H. H., and BATE, G. C. 1975.The growth of groundnuts {Arachis hypogaea L.) atthree altitudes in Rhodesia. Rhodesia Journal of AgriculturalResearch 13: 313.WILLIAMS, J. H., WILSON, J. H. H., and BATE, G. C. 1976.The influence of defoliation and pod removal ongrowth and dry matter distribution in groundnuts(Arachis hypogaea L. cv Makulu Red). RhodesiaJournal of Agricultural Research 19: 241.WILLIAMS, J. H., HILDEBRAND, G. L, and TATTERSFIELD,J. R. 1978. The effect of weather andgenotype x environment interaction on the yieldsof groundnuts (Arachis hypogaea L). RhodesiaJournal of Agricultural Research 16: 193.296

Session 8 — Country ReportsDiscussionP. SubrahmanyamYou mentioned that both rust and leaf spotsare important in Malaysia and that you wereusing benomyl as a fungicide. How are yougoing to control rust as benomyl will onlycontrol leaf spots? Secondly, what is the rangeof aflatoxins in Malaysian peanuts?H. B. HamatRust came to Malaysia only recently and so faris not a threatto groundnut cultivation. We arepresently controlling leaf spots with benomyland will have to change fungicides if rustbecomes serious. Aflatoxin levels in Malaysiangroundnuts have not been determined.R. P. ReddyYou state that in Malaysia lime is applied at therate of 1 tonne/ha. What sort of lime do youapply and is it to supply calcium or to changethe soil pH?H. B. HamatI am not sure what the source of lime is, but itis to combat the low pH of Malaysian soils,which are very acidic.R. O. HammonsYou mentioned that peanut is boiled in theshell in Malaysia. In what form is it eaten — asthe seeds or the whole fruit? In Bolivia youngboiled fruits are eaten whole.H. B. HamatOnly the seeds are eaten in Malaysia.R. W. GibbonsDo you manufacture your own Ultra LowVolume (ULV) spraying equipment inAustralia?K. MiddletonAt present we are importing ULV or CDA(Controlled Droplet Application) equipmentfrom the United Kingdom. But a subsidiarycompany in the USA is now manufacturingthis equipment on a large scale and thisshould be available on a large scale shortly.S. M. MisariThe pattern of plants wilting that you showedin one of your slides indicated that the affectedareas were scattered through the field, and yetthe field showed no obvious depressions.Have you investigated the soil properties, andhave you checked for soil pests in these wiltedareas?K. MiddletonWe have obtained negative results for soilpests and nematodes in these wilted patches.We feel that these patches are the result ofchanges in the physical structure of the soilscaused by intensive cropping and machinecompaction over the years.J. S. ChohanYou have mentioned that leaf spot and rust arecontrolled in Venezuela by fungicides. Whatfungicides do you use, and what costs areinvolved?B. MazzaniThe most important disease is leaf spot. Rust ispresent every year, but only occasionallydoes it'become serious, say every fifth or sixthyear. Benlate is commonly used to controlleaf spot, but many sprays are used and it is themost costly of all the inputs. One farmer toldme recently that he spent up to US$ 250 perhectare on leaf spot control.P. J. DartI was surprised to hear that you used 1tonne/ha of a 6:12:6 compound fertilizer ongroundnuts in Venezuela. This means that youare applying 60 kg of nitrogen. Do your experimentsshow the need for so much nitrogen?The implication is that the nodule nitrogenfixing system is not working effectively and297

would warrant some microbiological research.B. MazzaniThe soils in the groundnut growing regionsare very poor and contain practically no nitrogen.Experiments show that this amount offertilizer is required, and this question of highfertilizer usage in Venezuela is often askedbecause it is so unusual.Vikram SinghIn Venezuela there has been a significantincrease in yield, from 700 kg/ha in 1972 toover 1800 kg/ha in 1979. How have these largeincreases come about?B. MazzaniNot all the factors that have contributed to thisincrease have been analyzed, but I would thinkthatthe most significant singlefactor has beenthe increase in the area under irrigation.A. S. ChahalBreeding is under way in Brazil for resistanceto Aspergillus flavus but what about A nigerlIs this fungus also a problem?A. S. PompeuAspergillus niger is at present only a minorproblem in Brazil. The most important of alldiseases is leaf spot.K. MiddletonI would like to inform the delegates thatbesides Brazil, there is an interest in the use ofunrefined groundnut oil to power diesel enginesat the James Cook University inTownsville, Queensland. Groundnut oil hasbeen used as fuel in a diesel engine, and itproved to be competitive with normal dieselfuel.J. S. SainiI would like to ask the speaker from Malawi tocomment on weed control in that country. Weheard that weeds, particularly grassy weeds,are a real problem there and cause large yieldreductions.C. KisyombeGenerally, the weed problem is still tackled bymost farmers in the traditional way — b yusing the hand hoe or by hand pulling tallweeds. There has been some success with the"Lasso" brand preemergence herbicide on aresearch basis, and herbicides will be used bylarge growers.T. P. YadavThe average yields obtained by farmers inMozambique are very low — around 200 to500 kg/ha. What are the highest researchyields obtained?A. D. MalithanoDuring colonial times very little research workwas done on groundnuts as it was not a majorexport crop, so it was largely ignored. Thecurrent research program has only just startedand our first results gave us yields around 700to 900 kg/ha; but we are sure we can improveon these figures, particularly if we usesupplementary irrigation.J. S. ChohanWhat is the current staffing pattern forgroundnut research in Mozambique?A. D. MalithanoMany scientists left Mozambique after independencein 1975. At present I am the plantbreeder, and there is an FAO expert who has todivide his time with several other crops. Wehope shortly to recruit an agronomist and apathologist.J. S. ChohanThe extension agency in Mali seems to be veryeffective. Would you care to elaborate on this?D. SoumanoWe have separate extension and researchunits. Thedetailed data from research findingsare handed overto the extension agency. Theyare well-equipped with extension aids to carrythe information to the farmers. Research resultsare only carried to the farmers via extensionworkers, never directly.P. W. AminTermites appear to be important pests in Mali.Are they more troublesome as field pests orstorage pests? What control measures areused?298

D. SoumanoMost of the problems by termites are causedin the field, even before harvest. At present,Furadan is being used to control termites.Vikram SinghWhat are some of the morphological featuresand/or physiological traits identified by theworkers in Senegal that impart drought toleranceor resistance?J. GautreauFrom our studies morphological characters donot appear to be important. Two cultivars, onedrought resistant and the other not, can havevery similar morphological characters. Wefound differences between cultivars when wemeasured transpiration rate, stomatal resistance,and leaf water potential.Vikram SinghIn the fungicide trials in Zimbabwe you sometimesgot a depression in yield. Can you offeran explanation?G. HildebrandWe have not got enough data on this, but wesuspect that in dry years the treated plantsretain their leaves and lose too much water,whereas the untreated plants have lost someof their leaves due to disease and can withstandthe dry conditions.K. MiddletonWe have had similar experiences in Australia.The fungicides we use (chlorothanonil andfentin hydroxide) seem to affect the physiologyof the plant even when diseases are notprevalent. They help to delay maturity and theplants may wilt if sufficient water is not availablein heavily sprayed plots.D. V. R. ReddyIs 'clump' virus economically important inSenegal? Is rosette still important?J. GautreauIn Senegal 'clump' is present but in verylocalized small pockets. It is not economicallyimportant as yet but it has a very spectaculareffect on the plant.Rosette is more important in the south ofSenegal. A new resistant variety (69-101) hasbeen released, and where it is grown, rosetteis no longer a problem.R. W. GibbonsThe world record commercial yield of over 9tonnes/ha was achieved a few years ago inZimbabwe. Under what production practiceswas this yield obtained?G. HildebrandThe yield of 9.6 tonnes/ha was achieved in1973-74 in a comparatively dry year in theBulawayo region. The farmer planted early, hefollowed an irrigation schedule and used benlateand mancozeb for disease control. He didhowever use about twice the recommendedplant rate per hectare but he repeated theseyields over the next two seasons with thenormal rates of 1.25 to 1.5 million plants/ha. Heobtained these yields with the Makulu Redcultivar over an area of 30 acres.D. R. C. BakhetiaIn one of the slides during the presentationfrom Nigeria we saw stunted growth in onetrial that resulted from the effect of a fungicide.What was the fungicide?C. HarknessI would prefer not to disclose the name of thefungicide, which was an experimental formulation.We grew groundnut the next season onthe same area and the residual effects wereclearly apparent on the plots that had beentreated with this chemical.D. H. SmithI obtained similar results with an experimentalformulation, perhaps the same one. Stuntingof the plants was observed in residual peanutcrops for 2 years.W. V. CampbellI was surprised that so few insects werementioned as pests in the country reports,except as vectors of virus diseases such asrosette. Are insects not a serious problem or isit because there is a lack of detailed investigationson crop losses or entomologists workingin these countries?S. M. MisariI think that entomological aspects have been299

neglected. Very often people look only for thedramatic effects, e.g., a heavy infestation ofaphids that are easy to see. If you look carefully,the groundnut plant contains a richfauna. Over 70 insects have been reported tocause damage to groundnuts in Nigeria; apartfrom the noninsects such as termites andmillipedes, which are also important pests.C. HarknessWe got an unexplained increase in yield in the1979 season from insecticide-treated plots inNigeria. Treated plots gave 2600 kg/ha comparedto 1800 kg/ha from untreated plots. Wedid not determine which pest or pests wereinvolved.A. S. PompeuThere are many reports of insect pests ongroundnuts in Brazil but very few reports onthe actual losses due to pest attack. The majorpest in Brazil is Enneothrips flavens, which canreduce yields from 10to 100% with an averageof 30%.Vikram SinghAphids can cause 40% yield losses in India andthe red hairy caterpillar from 35 to 40% yieldloss.K. MiddletonGenerally, in Australia there are not seriouspest problems. Controlling mites and jassidsgives a cosmetic improvement in appearanceof the crop rather than a yield improvement.Large losses have been caused by whitegrubsbut no effective soil insecticide has yet beenapproved by the authorities. Heliothis cancause up to 35% defoliation without affectingyields.P. W. AminInsect pests are important in West Africa andso are millipedes and termites in Nigeria,Sudan, Upper Volta, and Senegal. Many farmersuse insecticides in the Sudan. Storagepests are also important, and they causequality losses as well as destroying seeds. Mysecond comment is that the entomologiststhemselves have not done enough on quantifyinglosses, particularly in financial terms.The first priority must be to obtain moreaccurate figures.D. R. C. BakhetiaCarbofuran 3G at 1 kg a.i./ha and carbofuran50% WP at 2.5 g a.i./kg seed have been foundto be very effective against white grubs inIndia. Yield increases of between 53 and 144%have been recorded by controlling whitegrubs.A. B. SinghYield losses due to white grubs and termitesvary from season to season and dependupon the soil type and the moisture level.Losses due to white grub may reach 80%.D. H. SmithWhat about the importance of nematodes,which have not been mentioned?S. M. MisariA seed coat inhabiting nematode has beenrecorded in Nigeria. Approximately 11 speciesof nematode have been reported fromgroundnuts. Much more work is needed in thisarea.R. O. HammonsSeed lots from Nigeria kept in a cold store atthe germplasm center in Georgia were foundto be infested with the seed coat nematodementioned by Dr. Misari. This poses a quarantineproblem.P. GillierWe get yield increases from applying carbofuranto the soil in Senegal, but so far it has notbeen determined whether these increases aredue to the control of nematodes or other soilinhabitants.J. GautreauIn 1975, nemagon-treated plots in Senegalgave yield increases of 39%, and there wasalso a significant residual effect. Nemagontreatment is difficult and expensive for smallscalefarmers.R. O. HammonsFive hundred germplasm lines were screenedunder controlled conditions in Georgia forresistance to the root knot nematode, but noresistance was found.300

Session 9Plenary Sessionand General DiscussionChairman: R. W GibbonsRapporteurs: D. McDonaldJ. P. MossD. V. R. RoddyJ. H. Williams

Plenary SessionThe Chairman opened this session with theremark that it should be kept as informal aspossible and although there were some specificpoints to be covered, any point could be raisedin the general discussion.The first item on the agenda was the reportsfrom the Chairmen of the sessions, in whichthey briefly summarized the papers and discussionspresented during the respective sessions.Following these reports, there was a generaldiscussion of the major points brought outduring the Workshop.Summary of Session 2Research Organizationand DevelopmentC. Harkness — ChairmanDelegates have been presented with a goodpicture of groundnut research organization anddevelopment in both developed and developingagricultural systems. Dr. Vikram Singh hasprovided a comprehensive report on the activitiesof the All India Co-ordinated ResearchProgram for Groundnuts, a large and complexorganization. The large numbers of scientistsand institutions concerned with research ongroundnut problems in India make an organizationsuch as AICORPO a necessity if costlyduplication of effort is to be avoided. Dr. Gilliergave an excellent description of the role of IHROin groundnut research and development withparticular reference to West Africa. His commentson seed multiplication are highly relevantand of great value to workers in developingcountries. Dr. Hammons talked aboutgroundnut production in Georgia. He describedthe advances and improvements in farmmachinery, weed control, crop protection,supplementary irrigation, and breeding whichhave together resulted in a high and stableproduction of groundnuts in Georgia. Dr.Hammons stressed the important part played inthis success story by the extension services.There is a great need to improve extensionservices in developing countries as many usefulfindings are not getting through to the farmer.Dr. Jackson's explanation of the Title XIIproject for cooperative research on groundnutsbetween USA institutions and research organizationsin the developing countries was particularlywell received by delegates. The benefits tobe obtained by such linkages should be evidentto all who have attended the present workshop.Summary of Session 3Genetics and Breedingft. O. Hammons — ChairmanIn the initial paper of this session, Dr. V. R. Raostressed the need for collecting and conservingthe world's groundnut genetic resources beforefurther genetic diversity is lost and as cropimprovement replaces ancient landraces. Developmentalactivities will soon result in theirretrievable loss of valuable genes. He tracedthe scope and present status of ICRISAT's dualefforts in the collection, maintenance, andevaluation of such germplasm and itsdocumentation and distribution. There havebeen substantial inputs to the germplasm bankfrom many countries as well as requests fordissemination. Each Workshop participantshould have gained the perspective of thespecial obligation that a groundnut scientistshould have to insure that the material alreadyassembled in a particular country should bemade available to ICRISAT and to secondarycenters.In discussing documentation. Dr. Rao reportedthat a descriptive language is underpreparation by which evaluations can be computerizedto facilitate information retrieval fromthe catalog. Finally, he pointed to the quarantineconstraints that are necessary to minimizethe possibility of introducing a new and destructivepest or pathogen into a country during seedtransfer.For improvement of the crop one starts with aportion of the available genetic variation and,through one of the basic techniques used in303

self-pollinated species, breeds for yield stabilityby one or more of the procedures outlined byDr. A. J. Norden. Here considerable interest wasshown in the multiline variety concept that hasbeen successfully employed in Florida, USA, tomaintain greater genetic diversity in new cultivarsthan that in the pure lines they replaced.This report described the successful cooperationamong U.S. breeders and the multidisciplinaryteam effort involved in research and developmentand introduction of new varietiesinto agricultural production and use by theconsumer.From a breeding program that has been incontinuous progress since 1928 in Florida, ourattention was directed by Dr. S. N. Nigam andco-workers to the 4-year-old program atICRISAT. Here the emphasis is not toward thedevelopment and release of the finished varietybut, rather, the emphasis has been and iscontinuing on producing and disseminatingsuitable breeding material to cooperators indifferent countries of the SAT. Under the conditionsat ICRISAT Center, exceptional numbersof cross-pollinations have been achieved, andvery large populations of bulked breeding linesare evaluated in appropriate field designs toprovide promising selections for distribution inareas that address many of the major constraintspresently limiting production in theSAT.The two papers presented in this sessionevoked considerable discussion. The majoremphasis has been on the analysis and use ofwild species that are currently available, andthis should be continued and expanded inscope to include newly collected material. Theapplication of D 2 analysis to chromosome armratios to increase the knowledge of relationshipsbetween wild species to facilitate theirutilization is of interest. Aneuploids have receivedlittle attention in the past, buttheseare ofimportance and more emphasis is needed,especially on their breeding behavior, becauseour knowledge of aneuploids in Arachis ismeager compared with the great advances thathave been made in some other crop plants, forexample Triticum and Nicotiana.The absence of reports on haploids in Ahypogaea either from twin seedlings or producedby anther culture was noted. Thesewould also be useful in isolating aneuploids.Another constraint on the utilization of wildspecies, especially on the production of amphiploidsand synthesis of A hypogaea from itswild ancestors, is that there is only one specieswith the B genome, and this limited the range ofdifferent amphiploids that could be produced.However, the production of hybrids and hexaploids,their screening for potentially usefulcharacters, especially disease resistance andyield potential, should receive high priority.The increased knowledge, with the improvedtechniques and the wider range of germplasmnow available, is leading to greater possibilitiesin the utilization of wild species of Arachis.Summary of Session 5Crop Nutritionand AgronomySummary of Session 4Cytogenetics and Utilization ofWild SpeciesV. S. Raman — ChairmanA. Narayanan — ChairmanThe environmental factors responsible for effectivenodulation in relation to crop growthneed extensive investigations in order to improvethe nitrogen nutrition of groundnuts. Theinfluence of fertilizer nitrogen with reference tonodule formation in the seedl ing stage was alsostressed. To determine the requirement of nitrogen,a proper balance sheet has to be workedout for various soil types and populargenotypes. It will aid in arriving at an appropriatecrop rotation. The utilization of biologicallyfixed nitrogen by a subsequent crop, especiallya cereal in a rotation, is an important area to beconsidered.Rhizobial strains are specific for genotype304

and location, thereby indicating no possibilityof having a universally efficient strain forgroundnut.The isogenic nonnodulating lines can be usedfor quantifying the nitrogen fixed by nodulesand the uptake from the soil. It is known thatnonnodulating character is genetically controlled,probably by two genes. Evidence is alsoavailable to show that genotypes differ in theirability to fix nitrogen.The mode of inoculation is an important basisfor better nodulation. The seed and/or soiltreatment(s) with fungicides, pesticides, or herbicidesmay influence the nodulation and fixationof nitrogen. Application of rhizobial inoculumbelow the seed, either in the liquid formor with sand, may help to avoid the harmfuleffects of fungicides used for seed treatment.Since the soils of the SAT areas are poor inphosphorus the exploitation of mycorrhizalfungi was also stressed.High partitioning and longer pod fillingperiod are the two important bases for yieldimprovement under optimum growing conditions.These two criteria, in addition to seedlingvigor and rapid canopy development etc., maybe used for breeding better genotypes for yield.However, in the SAT regions, the haulms ofgroundnut are used as cattle feed; thus itbecomes an economic yield. Therefore, thephysiological bases stressed above may not beapplicable for such conditions.Groundnut is intercropped with various cropsincluding cereals in various parts of the world.This system has proved to be physiologicallyefficient and economically feasible. Informationon the pattern of disease spread in this systemis to be gathered for making the system stillmore efficient.Summary of Session 6Groundnut EntomologyW. Reed — ChairmanThe Chairman opened the session with theobservation that entomology of groundnutshas always been an underrated input. Insectpests causefar greater losses to this crop than isgenerally realized. The cost of the insecticidespoured onto this crop worldwide far exceedsthat of the fungicides. In this workshop theentomology session had been allocated onehour, only two papers were presented, andthere were relatively few entomologists in thegathering.The first presentation was by Dr. Campbell,entomologist, and Dr. Wynne, plant breeder,both from North Carolina State University. Theydescribed their work on resistance ofgroundnuts to insects and mites. The resultsreported were impressive, with substantial resistanceto all of the major insect pests of theirarea having been discovered and subsequentlyutilized in commercial introductions. Resistanceto thrips, leaf hopper, Heliothis, andDiabotrica was described and illustrated. Inaddition substantial resistance to the twospottedmite was reported; this mite being aninduced pest following the use of insecticidesearly in the season. The current work is aimed atincreasing the levels of the resistance andcombining these with resistance to diseases,which has been developed by pathologists.Dr. Amin and Dr. Mohammad, entomologistsof ICRISAT reported on the current status oftheir groundnut pest research. Here the initialemphasis has been on the major pests on theICRISAT farm, i.e., thrips and jassids, with theprimary aim of reducing the damage in theresearch fields and so facilitating the researchof the groundnut scientists. The work wasstructured under three main headings, (1) surveyof the pest problems, (2) ecology andbiology of the major pests, and (3) screeninggermplasm for resistance.Although this program began less than 3years ago substantial progress was reported. Inparticular the work on Frankliniella schultzei,which is now known to be the major vector ofthe bud necrosis disease, has already given us ameans of reducing this problem in our fields,with early sowing, close planting, and preciselytimed insecticide use all contributing to a majorreduction of thedisease incidence. Initial resultsfrom screening the available germplasmagainst thrips, jassids, aphids, and termites lookpromising.There was limited time for questions and305

discussion, but it was evident that the representativesfrom India regard white grubs as themajor pest problem. These pests are devastatinglarge areas and are displacing this particularlysusceptible crop from several districts.Major questions asked were whether ICRISATcould take up research on these pests and wasthere any hope of host plant resistance being ofany utility against such polyphagous pests.It was pointed out that white grubs are notcommon at ICRISAT Center and the initial researchhas been concentrated upon the locallydamaging pests. In future, increased resourcesmay become available and at that time duepriority will be given to supplementing thenational efforts against this pest, if a suitablesite in an endemic white grub area can be madeavailable. The successes reported in locatingresistance to Heliothis, which is also apolyphagous pest, should encourage us in thesearch for white grub resistance. Another questionerbrought the attention of the meeting tothe importance of aphids as pests and vectors ofrosette in Africa.The Chairman had to cut short the discussionsbecause the allocated time had beenexceeded. He congratulated the speakers anddiscussants on their clear and precise contributions.The time limit ensured that the quantitywas limited but this was compensated for byhigh quality. The report by Dr. Campbell, whohad dedicated over 20 years to this work,exemplified the need for persistence in hostplant resistance research because worthwhileresults will only come with continuity. Far toomany programs are initiated and then changedor dropped after two or three seasons. TheICRISAT program had made a good, enthusiasticbeginning, and it is hoped that an expandingpest management research effort, aimed atpractical improvements at the small farmerlevel, will be built on these firm foundations.There was a clear advantage in cooperation andcommunication between research programsboth nationally and internationally. ICRISATcould derive enormous benefit from the wellestablishedprograms at North Carolina andelsewhere. The thrips, jassids, and Heliothismethodology and materials developed by Dr.Campbell will be of obvious value to the programbeing developed at ICRISAT, and it isessential that maximum advantage should bederived. We should not reinvent the wheel ineach and every research program.There is a clear need for an expansion inresources devoted to groundnut entomologyresearch. This need has been recognized, andICRISAT will be expanding its staffing andresources in this area in the near future.Summary of Session 7Groundnut PathologyJ. S. Chohan — ChairmanIt was strongly felt that diseases (fungal andviral) are causing the greatest constraints togroundnut production in the SAT. The researchesto date appear to be inadequate indepth regarding the biology, agroecology of thehost-pathogen systems and host resistance. Inspite of the good work conducted by someinstitutions/countries in the SAT and particularlyat ICRISAT Center, a lot more needs to bedone, particularly with respect to screening ofgermplasm and distribution of the resistantlines to countries in the SAT.Keeping this in view, although some goodgermplasm screening methods (epidemiological)have been perfected for some pathogens,more efforts are needed in this direction in theremaining economically important pathogens,especially the soilborne ones and the viruses.Concomitantly, additional laboratory equipment,screen houses, and other associatedfacilities are required.After intensification, all these inputs shouldlead to a major emphasis and breakthrough onthe development of stable disease resistance inthe not too distant future. It was envisaged thatlooking at the meager resources at the commandof the SAT farmers, regional programsshould now be strengthened to achieve theabove objectives. Close cooperation with scientistsin other disciplines is of paramount importanceto develop effective techniques in hostpathogen-environmentsystem(s), and thisshould be continued.306

Summary of Session 8Country ReportsA. W. Gibbons and J. P. MossCo-ChalrmanThe Chairman opened the session with theobservation that this was probably the mostimportant day of the Workshop because thedelegates would be hearing about groundnutproduction, utilization, research problems, andfurther research needs from 17 countries representingwidely different geographical areas,with widely different production methods.These methods ranged from completelymechanized systems to production methodsrelying almost entirely on hand labor, usingsimple tools or, at the most, bullock-drawnequipment. The Chairman also remarked thatthis session was particularly important to theICRISAT Groundnut Program scientists as theyare now at the stage where genetic materialsare becoming available for dissemination toother countries, particularly those in the SAT. Itwas important that the ICRISAT research goalswere matching the needs of client countries.The first session of the day was devoted toAustralia and Asia. The Australian groundnutsituation was rather unique in that although theproduction system was highly mechanizedthere were still serious deficiencies, particularlyin the supply of good quality planting seedOnly one rainfed crop is grown in a year anddrought is a common problem. At present theavailable planting seed was drawn from theindustry and it was often contaminated with A.flavus. Aflatoxin is, in fact, a very serious problemand is receiving a lot of attention. Incontrast, the Southeast Asian countries ofBurma, Malaysia, and Thailand are often able togrow two crops of groundnuts in a season. InMalaysia, groundnuts are often grown underplantation crops. Both Burma and Malaysiahave relatively young research programs. InThailand, the research infrastructure is moreadvanced and plans have been implemented toincrease production over the next 5 years. Ingeneral the disease and pest situation in SoutheastAsia does not appear to be as serious as it isin India, although the common diseases such asrust and leaf spots are always present. Thedevelopment of suitable cultivars to fit into thegroundnut farming systems, the need formechanization, and the strengthening of researchinputs are important in this region.The second group of papers covered the maingroundnut producing countries of SouthAmerica — Venezuela, Argentina, and Brazil.The production systems in Venezuela andArgentina are highly mechanized in contrast toBrazil where the production is mainly by smallscale farmers. In Brazil, two crops of earlymaturing groundnuts can be taken in a season.However, there has been a serious decline ingroundnut production in Brazil due to competitionfrom soybean. Leaf spots are prevalentthroughout the region, but rust is only a threat inVenezuela. In Brazil, the main pest is a species ofthrips. Valuable germplasm collections ofSouth American landraces are maintained atManfredi in Argentina, and wild species aremaintained in Sao Paulo, Brazil.The reports from Africa showed a wide rangeof variability in production methods, researchinputs, and problems. In many West Africancountries there has been a serious decline inproduction, mainly due to the succession ofdroughts, particularly in the Sahelian zone.Nigeria and Senegal have had a long history ofsuccessful and continuing research programs.Particularly noteworthy has been the breedingof rosette-resistant cultivars in Senegal, andlater in Nigeria, and the breeding of cultivarswith drought resistance in Senegal. Thetransferof technology from research findings to implementationby the farmer, however, remainsa problem in many of the African countries.The situation in Sudan, one of the leadinggroundnut producing countries, is in contrastto that of many of the other countries inAfrica as the bulk of the crop is grown underirrigation in the Vertisols of the Wad Medanischeme and yields average about 1440 kg/ha.These irrigated areas are mainly for the productionof large-seeded confectionery nuts for export.In the rainfed areas, early maturing cultivarsare grown and average yields are around600 kg/ha. Harvesting, however, is a problem onthe heavy Vertisols.Only recently has a fulltimeplant breeder been appointed.The reports from eastern and central Africa307

also showed some striking contrasts. Malawiand Zimbabwe have a long history of successfulplant breeding and disease control programs.Malawi produces a high quality confectioneryexport crop as well as cultivars for oil crushingto satisfy the internal demands for vegetablecooking oils. Zimbabwe has high input productionareas, which receive supplementary irrigation,and low input rainfed areas. Most of thecrop is used for local consumption. BothMozambique and Tanzania wish to increasegroundnut production but suffer from a lack ofconsistent research programs and germplasm.These countries have recently initiated breedingand agronomic research programs, but itwill be some time before results are obtained.In general, the disease and pest situation inAfrica is serious. Leaf spots and Aspergillusflavus are major pathogens and rosette virusstill presents serious problems although, resistantcultivars are available from both West andcentral Africa. Rust is now present in almost allof the major groundnut growing areas but is notserious at present, probably because only onecrop a year is usually grown, and the long dryseasons prevent a continuous inoculum beingpresent. Pests are important — particularlyaphids, white grubs, millipedes and thrips.Drought is a major recurring problem and theneed for more research effort in this area isimportant. The yield gap between the potentialyields and those actually obtained by the farmerwas reported from many countries.In conclusion the Chairman thanked all thespeakers for their excellent presentations and mparticular for keeping to the time allotted. Thepapers stimulated a great deal of useful discussionwhich was of immense value to theICRISAT program.General DiscussionChairmanThe Director General, Dr. L. D. Swindale,charged the delegates in his opening addresswith the task of evaluating and criticizing theICRISAT Groundnut Improvement Programand to make suggestions on how it could beimproved. We would be pleased to have theviews and suggestions of the delegates.J. S. ChohanI would suggest that the regional programsshould be strengthened and that more emphasisshould be put on training.ChairmanThe regional aspects of the Groundnut ImprovementProgram are being strengthened.In 1981, an outreach program will be startedon a regional basis in Central and EasternAfrica, and a similar program is due to commencein West Africa in 1982. Besides this, weare strengthening regional work in India andother countries through the national programs.In India, we are conducting research atstations that have been mutually agreed uponby the Indian Council of Agricultural Research(ICAR) and ICRISAT. We are also increasingour training through the Institute's trainingprogram and by giving specialist short-termtraining through our own program. Our staffgive lectures to the trainees, and this yearseveral in-service trainees from Africa andAsia are specializing on groundnut researchprojects. Besides this, we have research scholarsworking on M.Sc. theses at ICRISAT. Theydo their course work at the Andhra PradeshAgricultural University and their research atICRISAT. These scholars come from India,Ghana, and Benin. We expect to increase ourtraining activities in the very near future.J. M. TeriHas ICRISAT come up with the best methodsof advising national programs? I have in minda system whereby ICRISAT scientists canmake extended visits, lasting for 2 weeks orlonger, to work in situ with groundnut researchersin the SAT countries. This would be asequally important as the researchers comingto ICRISAT.ChairmanThis is exactly what does happen with ICRISATresearch scientists, particularly in the wellestablishedprograms. The Groundnut ImprovementProgram has been in a process ofbuilding up its center activities, and staff werestill being recruited in 1978 and 1979. We havealready made trips to S. America, Africa, Asia,and Australia. These trips will become morefrequent and, once the African program hasstarted, we will have ICRISAT scientists actu-308

ally based in Africa and working on a regionalbasis. They will visit the national programs intheir region as often as possible.T. P. YadavaI think that as drought resistance is one of themost important problems in the SAT, thisshould be extensively worked on at ICRISAT.The economic aspects of groundnut production,particularly in the field of pesticide use,should also be closely studied.ChairmanDrought resistance will become a major partof the ICRISAT physiology research program.The physiologist only joined just before theworkshop and is now recruiting more staff. Agreat deal of work has been done in this area inSenegal also, and we hope that strong cooperationcan be developed between theirprogram and ours.Similarly the economists at ICRISAT are nowgoing to look at the various economic aspectsof groundnut production.K. S. LabanaI would like to suggest that information relatingto the release of cultivars, new agronomicpractices, and many aspects of groundnutresearch should be released through an internationalnewsletter.ChairmanThis is in fact being considered by the ICRISATgroundnut program. International newslettersare already being circulated from the cereal andpulse programs. At the moment, the groundnutresearch community is well served by 'PeanutResearch', which is produced by APRES andwith which Dr. Hammons is closely associated.Perhaps he may care to comment?R. 0. HammonsThe APRES newsletter 'Peanut Research'could be reproduced and circulated globallyby ICRISAT. However, the world community ofgroundnut scientists would welcome and encouragethe initiation by ICRISAT of an 'InternationalGroundnut Newsletter'.ChairmanWe will certainly give this very serious consideration.D. H. SmithThere is a need for a global informationretrieval system for groudnuts including atranslation service and reprint service.ChairmanThis is also being considered. There is aninformation system for sorghum and millets atICRISAT which is being financially supportedby the International Development ResearchCenter (IDRC). It is called 'SMIC (Sorghum andMillet Information Center). It would certainlybe desirable to have such a system at ICRISAT,but this has been also discussed by otherorganizations.R. 0. HammonsI agree; various international organizationshave discussed the need for a computer-basedinformation center for groundnuts. Hopefully,such a system can be worked out.P. GillierIn the case of foreign publications, IHRO can,within the limit of their capabilities, furnish allthe information from their documentation system.ChairmanPerhaps Title XII could consider such a requestfor financing or operating such an internationalinformation system?C. R. JacksonIt could be a possibility, and also I would like tosuggest that there should be internationalmeetings of groundnut workers at regularintervals.J. S. ChohanAs an extension of the idea of publications tobe prepared by ICRISAT, it would be valuableto prepare annotated bibliographies, for example,on diseases of groundnut. Preferablythese could be prepared for individual diseaseswhen they are of major importance. Ifscientists had this sort of information theywould be better informed and would be moreeffective in workshops such as this one.V. RagunathanI agree. Several such handbooks have beenproduced by the sorghum and millet prog-309

ams and also by the chickpea program atICRISAT.ChairmanWe realize the importance of bibliographiesand handbooks, particularly those which willbe of value to field workers. A start has beenmade on this already. Two handbooks onaflatoxin procedures have been prepared and,in conjunction with Dr. Hammons, a rustmonograph is being prepared that will containan annotated bibliography.R. 0. HammonsIs sufficient work being done on improvingpreharvest technology? This subject wasbarely touched upon in this workshop. Thereappears to be a pressing need for improvingthe 'desi' plow, the lifting plow, and the smalldecorticator. If the work has been done, is theinformation being disseminated?ChairmanThe Farm Machinery Unit of the FarmingSystems Research Program at ICRISAT is currentlyworking on the improvement of equipmentfor the small farmer. This work willinclude equipment for groundnuts. A greatdeal of work has also been done to my knowledgein Senegal, Nigeria, Malawi, Botswana,and in India. This information should begathered together, if it has not already been,and then disseminated.C. HarknessCan ICRISATdo more in thefield of agronomicand herbicide research?ChairmanA certain amount of herbicide work has beendone, again by the Farming Systems ResearchProgram, at ICRISAT. However, at the outset ofthe program the consultants who outlined thegroundnut program for ICRISAT stressed thatmuch of the agronomic research needed ongroundnuts is very locale specific, and shouldbe done by the national programs. Agronomicwork is very much related to local soils andenvironments. When we commence our outreachprograms we will be more closely associatedwith this type of research.K. S. LabanaWhat are the possibilities of ICRISAT conductinginternational variety trials? The best varietiesfrom each country could be included andthis would give us information on their performanceover a wide range of environments.ChairmanThe idea is a good one and has been discussedbefore. One major problem has been thequarantine regulations of some countries.These problems include the import restrictionsbased on importing seed from certaincountries because of the disease situation inthe exporting countries. Many countries onlyallow limited seed to be imported and otherswill only release material that has been grownfrom seed to seed. All these restrictions makeit difficult to conduct global trials. We do havemost of the necessary material in ourgermplasm collection and this would have tobe multiplied first in the recipient country.Perhaps Dr. McCloud would care to commentbecause he tried to conduct international trialsafter the 1975 meeting held in Florida.D. E. McCloudThe International Peanut Program at the Universityof Florida collected about 33 of theworld's outstanding cultivars. These weremultiplied in Florida for distribution but fundswere not adequate or forthcoming to completethis project.R. 0. HammonsThe international variety trials concept hasbeen considered again by a panel of scientistsduring the past year. Under present quarantineconstraints it is difficult but the questionshould remain on future agendas.As mentioned, one of the problems is thelimited amount of seed which can be importedby some countries. This means that with somevarieties, which are in fact multilines, it wouldbe difficult to maintain their genetic integrity ifonly 5 to 10 seeds were allowed to be imported.For example, Florigiant is compositedfrom 8 components and 5 to 10 seeds of thiscultivar would not be sufficient.ChairmanWe have circulated a questionnaire preparedby the ICRISAT groundnut scientists which310

would provide a great deal of informationwhich would be useful for compiling informationon most aspects of groundnut production.We would like delegates to consider this questionnaireat length when they return home andmake suggestions on how it could be improved.If anyone has had time to read it, wewould invite comments now.J. S. SainiUnder the section on soils I suggest that thenutrient status of the soil may also be includedso that it can be correlated with fertilizer response.Rainfall figures should also be givenon a monthly basis rather than a seasonal onewith the average number of rainy days permonth. Average monthly temperaturesand relative humidity should also be included.The Chairman concluded the session bythanking all the people who had helped toorganize the workshop and, in particular, theparticipants who had presented papers and hadtaken part in the discussions. Professor C. Harkness,Ahmadu Bello University, Nigeria, onbehalf of the delegates thanked the DirectorGeneral of ICRISAT and his staff for invitingthem to ICRISAT and giving them the opportunityto take part in the Workshop.311

Appendix 1Poster Session

P o s t e r SessionThe following papers appeared in poster sessions or were distributed during the Workshop. Copiescan be obtained from the authors.Groundnut Breeding: Some ConsiderationsR. Pankaja Reddy and N. G. P. Rao*National Research Centre, IARI Regional StationRajendranagar, Hyderabad 500 030, India(•Present address- ICRISAT, PMB 1044, IAR, ABU, Samaru, Nigeria).AbstractEarly maturing bunch type groundnuts have largely been replaced by runner types in many parts ofthe USA. This subspecific shift has not taken place in India or Africa. Under uncertain rainfallsituations in India runners are grown but under the more assured conditions of irrigation bunchforms are grown, which is the reverse of the USA system. The question of whether the subspecificstatus of rainy and postrainy crops in India should be changed needs investigation. The moderncultivars in the USA are more efficient in partitioning photosynthates to the pods but this does notappear to be happening with Indian cultivars and priority should be given to this by breeders.Through the choice of suitable parents it should prove possible to generate material which is suitedto both rainy and postrainy seasons in India. Groundnut also offers scope for fitting into profitableand stable intercropping, relay cropping and sequential cropping systems. This again should be apriority research area.G r o u n d n u t R e s e a r c h a t P u n j a b A g r i c u l t u r a l U n i v e r s i t yOilseeds Section, Department of Plant BreedingPunjab Agricultural UniversityLudhiana, Punjab 141 004, IndiaAbstractGroundnut production has increased rapidly since the crop was first introduced in 1931. Presentlythe crop occupies 0.13 million hectares with an average yield of about 886 kg lha. About 82% of thecrop is grown under rainfed conditions, and groundnuts are rotated with irrigated wheat. Fivegroundnut cultivars have been released since breeding commenced, and one of these cultivars,M-13, has been released on a national basis. The cultivar M-13, however, is too late in maturityfor Punjab conditions, and it has been replaced by new cultivars. The latest cultivar, M-37, wasreleased in 1980, specifically for rainfed conditions. A new package of agronomic practices hasbeen evolved which has substantially increased yields. White grubs, aphids, leaf webbers, termites,and hairy caterpillars are serious insect pests. Considerable research has been conducted on thebiology and control of these pests, both by chemicals and by identifying sources of resistance. Of thediseases, collar rot and leaf spots are important and control measures have been recommended.315

Clump' virus is a relatively new disease and is causing concern. It appears to be soilborne, andmethods of control are being investigated.Production Problems in Groundnut — Impact of Improved TechnologyRelating Mainly to Conditions in the Punjab, IndiaJ. S. SainiAgronomist (Oilseeds), Punjab Agricultural University, Ludhiana, Punjab 141 004, IndiaAbstractOn the research farm the approved package of practices increased the pod yield by 133%, shelling by7.5%, total oil yield by 169%, and the haulm yield by 134% over the farmers' local practices. Themost important among the production factors were protective irrigation, weed control, harvesting atfull maturity and fertilizer application. Omission of these factors from the package of practicesreduced the mean pod yield by 33%, 32%, 26%, and 20%, respectively. Control of leaf spots was onlyimportant during a high rainfall season. When some of the more important practices were tested inunrep/icated large plots (0.4 ha) on farmers' fields they gave on an average yields of 1730 kglhacompared to 1170 kglha obtained from the local methods. This represented a yield increase of 48%.Future research strategies are also discussed to further enhance yields.Induced Mutants in Peanut (Arachis hypogaea)M. V. R. Prasad and Swamalata KaulIARI Regional Station, Rajendranagar,Hyderabad 500 030, Andhra Pradesh, India.AbstractIt was envisaged that the use of mutagens was a possible method whereby increased podproduction could be achieved with a reduction in plant canopy structure. Seeds of standard Spanishand Virginia cultivars were subjected to a wide range of mutagens such as gamma rays, EMS, andNMU in different doses. In the Spanish cultivars, mutants characterized by a compact canopy frameand short intemodes invariably produced fewer pods. Mutants with a large number of pods did nothave compact canopies. A Virginia runner mutant with narrow leaves was developed however froma Spanish cultivar. In addition to the narrow leaf character, there was an increased number ofnodules in the deeper areas of the root zone, a reduced susceptibility to leaf spots, an increase in podnumber and the seeds were non-dormant. In Virginia types it was possible to develop mutantscombining a compact canopy and more pods, as well as high yielding plants without anycompaction of the canopy. The useful mutants are being utilized in recombination breeding programs.316

The Differentiation and Identification of the Chromosomesand the Embryology of Arachis with Referenceto Alien Incorporation in GroundnutU. R. Murty, P. B. Kirti, M. B harati and N. G. P. RaoIARI Regional StationRajendranagar, Hyderabad 500 030 (A.P.)AbstractTriploid interspecific hybrids were produced between 10 varieties of Arachis hypogaea L and a wilddiploid species, A. chacoense (PI 276235). The hybrids exhibited varying chiasma frequencies,indicated differences in the pairing ability of the chromosomes in the different groundnut varietiesand suggested possibilities of increasing the success of alien incorporation. To enable generalcytogenetic studies, and particularly to identify alien addition and substitution races, the twentypachytene chromosomes of groundnut were identified, described and classified for the first time.The 'A' chromosome was found to correspond to a small chromosome that was completelyheterochromatic.To fill the gap in our knowledge of seed failure in some Arachis species, the embryology of arhizomatous species was studied. Fertilization proceeded slowly and incompletely and seed failurewas brought about by a cessation in the endosperm development and by a hyperplasticdevelopment of the endothelium. Triploid interspecific hybrids exhibited embryological featuressuggestive of non-recurrent apomixis.317

Appendix IIParticipants

ParticipantsArgentinaJ. R. PietrarelliINTA, Manfredi Research Station, 5988ManfrediAustraliaK. J. MiddletonDepartment of Primary IndustriesBjelke-Petersen Research StationKingaroy, QueenslandBrazilA. S. PompeuInstituto Agronomico, CP2813100 Campinas, S.P.BurmaU. Win NaingAgriculture CorporationMagwe DivisionMagweFranceP. GillierAnnual Oilcrops DepartmentIHRO, 11 Square Petrarque7501L, ParisEthiopiaA. KrauszP.O. Box 30726Plant Genetic ResourcesWest German EmbassyAddis AbabaIndiaV. ArunachalamNational FellowIndian Agricultural Research InstituteRegional StationRajendranagarHyderabad 500 030D. R. C. BakhetiaEntomologist (Oilseeds)Punjab Agricultural UniversityLudhlana 141 004PunjabA. S. ChahalPlant Pathologist (Oilseeds)Punjab Agricultural UniversityLudhiana 141 004PunjabJ. S. ChohanJoint DirectorPlant Disease ClinicCommunication CenterPunjab Agricultural UniversityLudhiana 141 004PunjabN. D. DesaiResearch Scientist (Oilseeds)Gujarat Agricultural UniversityJunagadh 362 001GujaratM. P. GhewandeScientist (Plant Pathology)Directorate of Oilseeds ResearchRajendranagarHyderabad 500 030B. S. GillNational FellowGujarat Agricultural UniversityJunagadh 362 001GujaratS. V. JaiswalGroundnut BreederPunjab Agricultural UniversityLudhiana 141 004PunjabN. C. JoshiDirectorCPPTIRajendranagarHyderabad 500 030K. S. LabanaSenior Oilseeds BreederPunjab Agricultural UniversityLudhiana 141 004PunjabD. P. MisraDirectorNational Research Centre for Groundnut (ICAR)Opp. TimbawadiJunagadh 362 002321

V. V. ModhaChief AgronomistThe Vanaspati Manufacturers' Association of India6th Floor, Harilela House28/32 Mint RoadBombay 400 001U. R. MurtyNational FellowAll India Coordinated Sorghum Improvement ProjectIARI StationRajendranagarHyderabad 500 030A. NarayananProfessor of Crop PhysiologyAndhra Pradesh Agricultural UniversityRajendranagarHyderabad 500 030G. D. PatflOilseeds SpecialistMPKVJalgaon 425001MaharashtraS. H. PatilBhabha Atomic Research CentreBiology & Agriculture DivisionBombay 400 085M. V. R. PrasadGeneticistIndian Agricultural Research InstituteRegional StationRajendranagarHyderabad 500 030V. RagunathanDeputy DirectorCPPTIRajendranagarHyderabad 500 030N. RajagopalAssistant Oilseeds SpecialistReg tonal Oilseeds Research StationKadirl515 501Anantapur District, A.P.V. S. RamanProfessor & Cytogenetlcist (Oilseeds)Tamil Nadu Agricultural UniversityCoimbatore 641 003V. RavindranathPlant PathologistIARI Regional StationRajendranagarHyderabad 500 030C. Raja ReddySenior Scientist, Groundnut BreedingNational Agricultural Research ProjectS.V. Agricultural CollegeTirupati 2M. S. S. ReddyOilseeds SpecialistAndhra Pradesh Agricultural UniversityAgricultural Research InstituteRajendranagarHyderabad 500 030M. V. ReddiHead, Department of Plant BreedingCottege of AgricultureBapatlaP. S. ReddyProject Coordinator (Groundnut)Punjabrao Krishi VidyapeethAkola 444 104MaharashtraR. Pankaja ReddyGroundnut GeneticistAll India Coordinated Sorghum Improvement ProjectRajendranagarHyderabadJ. S. SainiAgronomist (Oilseeds)Department of Plant BreedingPunjab Agricultural UniversityLudhiana 141 004PunjabI. S. SekhonDepartment of Plant BreedingPunjab Agricultural UniversityLudhiana 141 004PunjabA. B. SinghBreeder (Groundnut)Groundnut Research StationMainpuri 206001Uttar Pradesh322

Vikram SinghProject DirectorDirectorate of Oilseeds ResearchRajendranagarHyderabad 500 030S. ThangaveluBreeder (Oilseeds)Cashew Research StationVriddhachalam 606 001South Arcot DistrictTamil NaduT. P. YadavaProject LeaderDepartment of Plant BreedingMaryana Agricultural UniversityHissarHaryana 125 004MalawiC. T. KisyombeMinistry of Agriculture & Natural ResourcesChitedze A.R.S.P.O. Box 158, LilongweD. E. McCloudInternational ProgramsUniversity of FloridaChitedze A.R.S.P.O. Box 158, LilongweP. K. SibaleMinistry of Agriculture & Natural ResourcesChitedze A.R.S.P.O. Box 158, LilongweMalaysiaH. B. HamatField Crop Research StationLot 206/94 Sect. 20Jalan Raja Dewa HuluKota Bham, KelantanMaliD. SoumanoRecherche AgronomiqueDe SotubaB.P. 258BamakoMozambiqueA. D. MalithanoFaculty of AgricultureUniversity of Eduardo MondlaneC.P. 257, MaputoNigerA. MounkailaSection ArachideCNRA/TarnaB.P. 240, MaradiNlgariaC. HarknessInstitute for Agricultural ResearchAhmadu Beilo UniversityPMB 1044, ZariaS. M. MisariInstitute for Agricultural ResearchAhmadu Bello UniversityPMB 1044, ZariaSenegalJ. GautreauInstitut Senegalais de Recherches AgricolesCNRA de BambeyO. De PinsInstitut Senegalais de Recherches AgricolesCNRA de BambeySudanM. A. AliAgricultural Research CorporationDirector General's OfficeWad MedaniH. M. IshagAgriculture Research CorporationGezira Research StationWad MedaniTanzaniaA. BoltonODA Oilseeds TeamAgricultural Research InstituteP.O. Box 509MtwaraA. L. DotoUniversity of Dar es SalaamDepartment of Crop ScienceP.O. Box 643Morogoro323

N. FivawoResearch DivisionMinistry of AgricultureP.O. Box 7091Dar es SalaamJ. M. TeriUniversity of Dar es SalaamDepartment of Crop ScienceP.O. Box 643MorogoroThailandT. CharoenwatanaFaculty of AgricultureKhon Kaen UniversityKhon KaenA. Na LampangField Crop DivisionDepartment of AgricultureBangkhen, BangkokD. TiyawaleeFaculty of AgricultureChiang Mai UniversityChiang MaiUSAM. K. BeuteDepartment of Plant PathologyNorth Carolina State UniversityRaleigh, NC 27650W. V. CampbellDepartment of EntomologyNorth Carolina State UniversityP.O. Box 5215Raleigh, NC 27650D. CumminsAssociate Planning DirectorPeanut CRSPGeorgia Experiment StationExperiment, Georgia 30212R. 0. HammonsUSDA-SEACrops Research UnitCoastal Plain StationP.O. Box 748Tlfton, Georgia 31793C. R. JacksonPlanning DirectorPeanut CRSPGeorgia Experiment StationExperiment, Georgia 30212A. J. NordenAgronomy DepartmentUniversity of FloridaGainesville, Florida 32611D. M. PorterUSDA-SEAPeanut Research UnitTidewater Research CenterSuffolk, Virginia 23437D. H. SmithTexas Agriculture Experiment StationTexas A & M University SystemP.O. Box 755Yoakum, Texas 77995H. T. StalkerDepartment of Crop ScienceNorth Carolina State UniversityRaleigh, NC 27650J. C. WynneDepartment of Crop ScienceNorth Carolina State UniversityRaleigh, NC 27650VenezuelaB. MazzaniCENIAP-IIAAP. Postal 4653Maracay, 20101ZimbabweC. L. HildebrandCrop Breeding InstituteP.O. Box 8100CausewayICRISATADMINSTRATIONL. D. Swindale, Director GeneralJ. S. Kanwar, Director of ResearchJ. C. Davies, Director for International CooperationGROUNDNUT IMPROVEMENTPROG RAMP. W. Amin, Entomologisti. S. Campbell, International InternP. J. Dart, Principal MicrobiologistS. L. Dwivedi, Plant Breeder324

A. M. Ghanekar, VirologistR. W. Gibbons, Principal Plant Breeder and ProgramLeaderT. Goto, International InternD. McDonald, Principal Plant PathologistV. K. Mehan, Plant PathologistA. B. Mohammad, EntomologistJ. P. Moss, Principal CytogeneticistP. T. C. Nambiar, MicrobiologistD. J. Nevill, International InternS. N. Nigam, Plant BreederD. V. R. Reddy, Principal VirologistD. C. Sastri, CytogeneticistA. K. Singh, CytogeneticistP. Subrahmanyam, Plant PathologistJ. H. Williams, Principal PhysiologistFARMING SYSTEMS RESEARCH PROGRAMC. N. Floyd, International IntermM. S. Reddy, AgronomistR. W. Willey, Principal AgronomistGENETIC RESOURCES UNITV. R. Rao, BotanistWORKSHOP EDITOR:J. V. Mertin, 6 Watson Street, Fullarton 5063, SouthAustraliaFRENCH INTERPRETERSMrs. T. N. RainaM-19 Greater Kailash INew Delhi, IndiaMrs. Pushpa SinghalAsian African LegalConsultative Committee27 Ring Road, Lajpat Nagar IVNew Delhi, IndiaA-0023325

ICRISATInternational Crops Research Institute for the Semi-Arid TropicsICRISAT Patancheru P.O.Andhra Pradesh 5 0 2 3 2 4 , Indiavokils