واکنش لاین‌های گندم نان به بیماری زنگ زرد در آزمایشات مقدماتی عملکرد در گرگان

Yellow rust disease (Puccinia striiformis f. sp. tritici) is the most important wheat disease in Iran and it is observed in most parts of the country. The warm and humid agro-climatic zone of northern Iran is prone to the emergence of this disease due to high relative humidity. The use of resistant cultivars is the most economical way to control this disease. In this study, 160 bread wheat genotypes in preliminary yield trials were evaluated for yellow rust disease n Gorgan agricultural research station in the 2019-2020 cropping season. To further spread the yellow rust infection, Falat cultivar (susceptible) was cultivated in the margin of the trail. Tirgan cultivar was also used as a resistant control in the trial. After complete establishment of the disease on the susceptible cultivar in the adult plant stage, data were recorded based on the infection type, as susceptible (S), Moderately susceptible (MS), resistant (R), Moderately resistant (MR) and immune (O). Infection intensity was also graded from 0-100. The coefficient of infection (CI) was calculated by multiplying the infection intensity in the constant values that is related to the plant response (O = 0, R = 0.2, MR = 0.4, MS = 0.8 and S = 1). Due to the favorable climatic conditions for the pathogen, in March and April, yellow rust disease was well established and spread. The results showed that based on the infection type, 42 lines (26%) were moderately resistant and 36 lines (23%) were moderately susceptible and 27 lines (17%) were susceptible to yellow rust. Also, no signs of infection were observed in 55 lines (34%). Based on coefficient of infection (CI), 63 lines (39%) were resistant, 26 lines (16%) were moderately resistant, 4 lines (3%) were moderately resistant to moderately susceptible and 10 lines (7%) were moderately susceptible. Of the top 10 lines in terms of grain yield, four, five and one lines were immune, resistant and moderately resistant to yellow rust disease, respectively.