Study on Virulence Factors of Mycosphaerella graminicola, the Causal Agent of Septoria Leaf Blotch and Reactions of Some Iranian Wheat Genotypes to this Pathogen in Iran

Septoria leaf blotch disease caused by Mycosphaerella graminicola is one of the most important diseases of wheat in Iran and around the world. Evaluation the reaction of wheat genotypes as well as identifying pathogen virulence factors is required in order to achieve a successful breeding program. The aim of this study was to assess the adult plant responses of Iranian bread wheat and durum wheat genotypes (developed by Iranian seed) Septoria tritici leaf blotch. Furthermore, this study has aimed surveying the virulence factors of this pathogen in warm and humid weather conditions of the south of Iran. Thus, the study was conducted in one of southern provinces of Iran, Khuzestan, for two sequential years (December 2013-May 2014 and December 2014-May 2015) and included 47 commercial varieties and 26 differential lines with a local pathogen isolate that was collected on a bread wheat variety. Data records were performed with a modified Saari and Prescott method in double-digit scale of 00–99. According to the results, from all commercial varieties, 5 varieties were resistant. Surprisingly, the durum varieties like Behrang and Karkhe were susceptible too. Based on the results of differentia-tion tests showed that the pathogen isolate of this region has virulence reaction against stb2, stb3, stb4, stb6, stb7, stb8, stb9, stb10, stb12, stb13, stb14, and stb18 genes and avirulence reaction against stb1, stb5, stb11, stb15, stb16, and stb17 genes.