ارزیابی مقاومت نسبی به بیماری سفیدک پودری در ارقام تجاری و تعدادی از لاین های امید بخش جو به روش اندازه گیری سطح زیر منحنی پیشرفت بیماری

Powdery mildew of barley caused by Blumeria graminis f.sp. hordei, is one of the most important diseases of barley in major barley production regions in Iran. More than 100 race-specific resistance genes to powdery mildew have been found in barley. However most of these sources of resistance become ineffective after a few years of cultivation due to appearance of new physiological races of the pathogen. Plant breeders are continuously searching for sources of partial resistance that usually is under the control of several genes with minor effect and is more durable. The objective of this study was to evaluate the level of partial resistance to powdery mildew in elite lines and commercial cultivars of barley. Evaluation of resistance was conducted at adult plant stage under the natural conditions of disease epidemic at Agricultural Research Stations of Torogh (Mashhad), and Araghi Mahale (Gorgan). From the total number of 56 lines and cultivars evaluated in Gorgan, 6 lines were resistant, 25 lines were evaluated as moderately susceptible and 25 lines as susceptible. Results of powdery mildew evaluation in Torogh stations using the area under the disease progress curve (AUDPC) showed that in 54% of genotypes relative AUDPC was less than 50%, indicating that they have high level of partial resistant. Results of this study will be used for the selection of superior lines that show desirable morphological and agronomical traits and in powdery disease management.