ارزیابی لاین‌های گندم نان حاصل از دورگ‌گیری از نظر بیماری سفیدک سطحی

Powdery mildew disease is one of the most important wheat diseases in humid and semi-humid regions of the world. The Caspian Sea region is prone to the emergence of this disease due to high relative humidity. The use of resistant cultivars is the most economical and environmentally way to reduce the application of chemical fungicides. In this study, in order to select the best lines derived from hybridization, 128 spring bread wheat genotypes were evaluated as observational approach in plots with an area of 5.5 m2 at Gorgan Agricultural Research Station. The lines were evaluated for powdery mildew disease at the adult plant stage and full emergence of flag leaf, after complete establishment of the disease on susceptible cultivar. Powdery mildew was recorded by Saari and Prescott methods with a scale of 0-9. Due to the favorable climatic conditions for the pathogen, in March and April, powdery mildew disease was well established and spread. The results showed that the majority of the lines were moderately susceptible and susceptible, so that 55 lines (43%) were also moderately susceptible and 46 lines (35.9%) were susceptible to powdery mildew. While 16 lines (12.5%) were resistant to powdery mildew. Also, no signs of infection were observed in 10 lines (7.8%). As well as, none of the lines were in the group of highly resistant or highly susceptible. Of the top 10 lines in terms of grain yield, four, one and five lines were immune, resistant and moderately susceptible, respectively.