گزارش نهایی طرح تحقیقاتی ارزیابی مقاومت ارقام و لاینهای پیشرفته گندم دیم نسبت به بیماری زنگ زرد در مراحل گیاهچه ای و گیاه کامل در شرایط گلخانه ای و مزرعه ای

‭Evaluation of Resistance of some Raiu-fed Bread Wheat Advanced Lines and CUltiva" to Y eHow Rust at Seedling and Adult-Plant Stages Abstract In the present investigation, resistance of 184 rain-fed bread wheat advanced lines and cnltivars were evaluated to yellow rust for two years. Wheat entries were evaluated at adult‬ص ‭plant stage in field (under artificial epidemic conditions in eight locations) and at seedling resistance in greenhouse to identiIY adult-plant and seedling resistance 1'espectively. In field tests wheat entries were planted during the last week of November 2000 (first year) and 2001 (second year), at the rate of 8-10 g of seed in two 1m long rows and spaced 30cm apart. A susceptible cultivar (Bolani) was planted among the experimental entries (10 entry intervals) and also borders of the nurseries. Artificial inoculation of the nurseries was done four times in a period of two months starting at tillering stage using the relevant race of each location. The infection type (IT) of each entry Was evaluated when the disease developed well on susceptible check. The percentage leaf area affected was also scored using Cobb's modified scale at the same time and coefficients of infection (CI) were calculated. To evaluate the resistance of the genotypes at seedling stage, seeds 184 accessions were planted in Scm diameter pots (4-6 seeds per pot) in the greenhouse. The seedlings Were inoCulated with fresh harvested urediniospores of an isolate of Puccinia striiformis f.sp. trifici (isolate collected fi'om Karaj) 9 days after sowing, when the first seedling leaves were fully expanded Inoculated plants were placed inside a small plastic covered cage and kept at I 0 "C and 90% RH in the darkness for 48 bro, and then transfelTed into a greenhouse at 15 "C. The reaction of each line or cultivar was evaluated using McNeal ef al, (1971) scale 15-17 days after inoculation. A heavy epidemic of the disease was established in the nurseries of Karaj, Miandoan, and Moglian, in the first year of field tests but it was relatively light in other locations. Based on data of Karaj, Miandoan, and Moghan, most of entries were resistant to yellow rust in one or more locations and 114 entries (about 62% of the genotypes) were resistant in all of locations. Based on data of Karaj, Miandoan, Moghan, and Maragheh (with a heavy epidemic of disease) in the second year of field tests, most of entries were resistant to yellow rust in one or more locations as well. Results showed that 87 entries (about 47% of the genotypes) were resistant in all of locations. Integrating the results of first and second years of field tests showed that 74 entries (about 40% of the genotypes) had high levels of resistance to yellow rust in two years and in different locations. The results of seedling tests indicated that most of entries were susceptible to the yellow rust isolate ofKaraj at seedling stage. ri‬

Keywords:

گندم , زنگ زرد گندم , بیماری ها , دیم کاری , آفت ها , آفت , آفت