بررسی مقاومت به بیماری زنگ زرد در گندم بهاره با پایش آزمایش مقایسه مقدماتی عملکرد

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, 233 bread wheat genotypes in preliminary yield trials were evaluated for yellow rust disease n Gorgan agricultural research station in the 2020-2021 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, 27 lines (12%) were moderately resistant and 26 lines (11%) were moderately susceptible and 38 lines (16%) were susceptible to yellow rust. Also, no signs of infection were observed in 142 lines (61%). Based on coefficient of infection (CI), 51 lines (22%) were resistant, 6 lines (3%) were moderately resistant, 10 lines (4%) were moderately resistant to moderately susceptible, 20 lines (9%) were moderately susceptible and 4 lines (2%) were susceptible. Of the top 10 lines in terms of grain yield, five, four and one lines were immune, resistant and moderately resistant to yellow rust disease, respectively.