Assessment of Wheat Cultivars for Resistance to Mycosphaerella Graminicola Isolates from Moghan Plain at Seedling Stage under Greenhouse Conditions

Septoria tritici blotch (STB), caused by Mycosphaerella graminicola (anamorph: Septoria tritici), is one of the most important diseases of wheat worldwide that has been intensified recently in some regions of Iran including Moghan Plain. In this study reaction of 23 bread and durum wheat cultivars to 10 isolates of the pathogen collected from Moghan region during 2007 and 2008, were evaluated under greenhouse condition. Analysis of variance (ANOVA) of pycnidial coverage of leaf areas revealed significant differences (P<0.01) among fungal isolates as well as wheat genotypes. Moreover, genotype× isolate interaction term in the ANOVA analysis was highly significant (P<0.01), indicating isolate-specific interaction between wheat cultivars and fungal isolates. Although about half of wheat cultivars were susceptible to all isolates, 40 isolate-specific resistances were identified that most of them are new records. Among the new sources of resistance, Dehdasht, Seimareh, Galanco, Saisson and Hirmand with specific resistance to nine, eight, six, five and three isolates, respectively, were the most resistant cultivars. Furthermore, the isolates exhibited different virulence patterns on wheat cultivars. Although results of this study indicated high virulence diversity of M. graminicola isolates from Moghan Plain and susceptibility of the most wheat genotypes cultivated in this region to STB, the new sources of resistance could be utilized in the wheat-breeding programs.