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The Wheat Program's structure and the role of outreach/regional programs have been described. It wasnoted that outreach staff did not have their own programs but rather worked within the national programs,giving technical support and training and, where feasible, financial support for equipment.The Wheat Program Crop Protection Unit has as its major objective to aid in increasing wheat productionand productivity through breeding support, research, training, and technical assistance in wheat pathology.Details of our organization and staff were discussed. The following are the diseases of concern at present:rusts; foliar blights and blotches; fusarium scab; smuts and bunts, and BYD.Highlights of recent research at CIMMYT were given for specific diseases with emphasis on diseases ofimportance In Russia and Ukraine.Adult plant (= slow rusting or rate limiting) resistance concepts were presented and discussed. It wasemphasized that we believe this type of resistance, as a whole, will be longer lasting than thehypersensitive, major gene type. We are attempting to combine diverse sources of this type of resistancefor leaf rust. Genetic studies indicate that many genes are involved in this kind of resistance in CIMMYTmaterials. Prominent are the Frontana and Pavon leaf rust resistance complexes. A study on RUSSian andUkrainian spring bread wheats done at CIMMYT indicated that the Frontana complex type of resistance iscommonly present in these wheats as are other sources of adult plant resistance, i.e., slow rustingresistance genes. Discussions were held on identifying slow rusting resistance and incorporating it intogermplasm.Further discussions were held on slow rusting resistance to yellow (stripe) rust. It was noted that, inCIMMYT germplasm, Anza-type durable slow rusting resistance is present as the Yr18 complex. In Pavonthere are other sources of durable slow rusting resistance genes (probably 3-4). It appears that slow rustingresistance sensu Parlevliet is not present in the wheat:yellow rust system. The resistance is likely due todelayed primary hyphal growth.Durable stem rust resistance worldwide appears to be due to a complex of genes linked to Sr2 derived fromthe cultivar Hope. No stem rust epidemics have occurred for many years in areas where this resistance hasbeen in use.Genetic studies on the basis of slow rusting and adult plant resistance for leaf and yellow rust are beingconducted at CIMMYT. There are clear indications that a range of resistance genes are involved.Information was presented on some of the best available spring bread wheat germplasm for resistance/tolerance to septaria tritici blotch (Tinamou, Catbird, Bobwhite, Milan); scab (Sumai 3, Wuhan 1,2,3, Suzhue6, Frontana); powdery mildew (Kalyansona); BYD (Anza, Milan, Th. intermedium); eyespot (Rendezvous,Cappel Ie Desprez. Cerco), and common root rot (Marshall, Thatcher, Nordic, Norseman).Discussions were held on how to increase cooperation and promote the exchange of germplasm andinformation.2
Wheat Germplasm Improvement at CIMMYT MexicoS. Rajaram 1 and A.!. Morgounov 2IntroductionIn 1994 the Wheat Program celebrated 50 years of wheat breeding at CIMMYT and Its predecessororganization. the Office of Special Studies (founded in 1944 by the Government of Mexico and theRockefeller Foundation). Within a span of 50 years, wheat breeding has evolved through three majorstrategic phases: 1) the bilateral phase (1944-1960) within Mexico; 2) the Green Revolution phase (19611976): Internationalization of CIMMYT wheat breeding, and 3) the Post-Green ReVOlution phase (1977present): globalization of CIMMYT wheat breeding.Bilateral phase within Mexico (1944-1960)During this 16-year penod, stem rust resistance of a durable nature, derived from the variety Hope andbased on the Sr2 complex was bred into adapted Mexican germplasm. Thus. the threat caused by thisdisease was virtually eliminated. Shuttle breeding, a revolutionary breeding methodology was implemented.This permitted selection of photoperiod insensitivity (based on the genes Ppd1 and Ppd2) , which wouldallow adaptation of the gene pool far beyond Mexico. Dwarfing genes of Japanese origin (Rht1 and Rht2)were incorporated into the stem rust-resistant and photoperiod-insensitive varieties to reduce plant height. Ifeither Rht 1 or Rht2 are present. the reduction is 40 cm; if both genes are present the reduction is 55 cm.Consequently, lodging tolerance under optimum irrigation and high fertility conditions was achieved. theoutcome of this experiment was revolutionary and resulted in the production of semidwarf advanced linesshOWing a yield advance of more than 50%. The essence of wider adaptation of the germplasm had beencreated.Green Revolution phase (1961-1976)CIMMYTs breeding program was internationalized through the establishment of International Nurseries inthe 60s. Diverse agroecological regions such as the Indo-Gangetic Plains of the Indian Subcontinent, theNile Valley, the Mediterranean Basin, the Humid Pampa region of Argentina, and the high rainfall/irrigatedcoastal and pre-Cordillera areas of Chile were recognized as requiring focused efforts within CIMMYTsoverall mandate.• T~e major breeding initiatives during this period were the following:• Exploitation of the spring x winter gene pool with additional assistance through a cooperative venturebetween CIMMYT and Oregon State University in the USA.• Septoria leaf blotch resistance in semidwarf wheats with additional assistance through a cooperativeventure between CIMMYT, Tel Aviv University in Israel, and IPO, Wageningen, Holland., CIMMYT Mexico.2 CIMMYT. PK 39 Emek 06511, Ankara, Turkey.3
Page 3: CIMMYT is an internationally funded
Page 8 and 9: Slow rusting genes to leaf rust wer
Page 10 and 11: The seven-cycle scheme outlined bel
Page 12 and 13: ME4: Low rainfall; 21.6 million ha:
Page 14 and 15: The International Winter Wheat Impr
Page 16 and 17: approach it is possible to select f
Page 18 and 19: Eyupoglu et al. (1993) showed that
Page 20 and 21: Selected activities and accomplishm
Page 22 and 23: 3. Double crosses F1 (S x W) x F1 (
Page 24 and 25: The data presented here allowed us
Page 26 and 27: Table 3. The relationship between a
Page 28 and 29: Role of International Wheat Nurseri
Page 30 and 31: involved parties. We should have re
Page 32 and 33: characteristics of some recent wint
Page 34 and 35: Backcrossing of the hybrids with th
Page 36 and 37: In 1974 the Institute submitted the
Page 38 and 39: History, Achievements, and Perspect
Page 40 and 41: translocation. These are Kavkaz, Au
Page 42 and 43: Lee J-H., Graybosch R.A., Kaeppler
Page 44 and 45: Table 3. Derivatives of Russian cul
Page 46 and 47: is based on a cross Lutescens 6915/
Page 48 and 49: The combined resistance to leaf rus
Page 50 and 51: Developing Winter Wheat Germplasm o
Page 52 and 53: Table 2. Winter hardiness and other
Page 54 and 55: squ produced 2% awnless plants in M
Page 56 and 57:
grains per spike and spikelet as we
Page 58 and 59:
p' jsiology and Biochemistry Resear
Page 60 and 61:
Phytopathological Characteristics o
Page 62 and 63:
Resistance to S, tntiei is manifest
Page 64 and 65:
Breeding aimed at developing winter
Page 66:
wheats are more easily transformed
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