the Symposium on Wheats for More Tropical Environments - cimmyt

69primarily due to a lack of finances on<strong>the</strong> part of <strong>the</strong> majority of farmers forimplementing modern technology forwheat production. Thus, <strong>the</strong>re is greatscope for improving wheat productionand yield in <strong>the</strong> country.CODstraints to ProductionLike many developing countries, wheatproduction is confronted with bothbiophysical constraints (disease,fertilizer, water, seed, varieties, culturalpractices and salinity/sodicity) andsocioeconomic constraints (credit,knowledge, experience, tradition andinstitutions).DiseaseAlthough several diseases attack wheat,<strong>the</strong> most important are stripe and leafrusts, loose and flag smuts, Kamal bunt.powdery mildew, helminthosporium leafspots and foot and root rots. O<strong>the</strong>rdiseases,such as those caused bySeptoria spp., downy mildew, blackpoint and black chaff, are of minorimportance. The major thrust in <strong>the</strong>breeding program at present is todevelop wheat varieties which areresistant or tolerant to <strong>the</strong> principaldiseases. Measures to minimize <strong>the</strong>iradverse effects on production are alsobeing investigated. The reactions ofcommercial wheat varieties to importantdiseases are shown in Table 1.Table 1. Reactions of commercial wheat varieties to six diseases, PakistanDisease reaction.NYellow Leaf Loose Flag Powdery CompleteVariety rust rust smut smut mildew buntBlue Silver S S S S S SBarani 83B/ MR-MS MR-MS S R SIndus 79 MS MS S S SBahawalpur 79 MS-S MS-S S S SLU26 S MS-S S MR RLyallpur 73 S S S S S SPARI73 MS-S S S S S SSandal MR-S S S MR S SSonalika MS-S S S S SPunjab 81 MS-S MR S S SPakistan 81 MR MR S S RFaisalabad 83B/ R R S MR SArz MR-MS MR S S SZamindar 80 MR-MS MS S S SZargoon 75 MR S S S SKhyber 79 MR-MS SJauhar 78 S SSarhad 83~/ R RKohinoor 83 ~/ R R S S S.J./ S = susceptible, MS = moderately susceptible, M R = moderately resistant,R = resistant9./ Candidate for release