Identification of Resistance Sources to Septoria tritici Blotch with Causal Agent Zymoseptoria tritici in Bread Wheat Genotypes

The Septoria tritici blotch disease (STB) caused by Zymoseptoria tritici is one of the most important wheat diseases in the world as well as Iran. Genetic resistance is one of the most efficient and economical strategies to control this disease. Identification of resistance sources in wheat genotypes is necessary to control STB. In this study, 33 spring bread wheat genotypes were evaluated against five Z. tritici isolates at seedling stage. Of 33 genotypes, 10 genotypes showed resistance to one or more isolates., Nogal, Arta and N-92-9 genotypes were highly resistant to all isolates tested that show these genotypes possess known or novel effective resistance genes that can be used as resistance sources to the STB in wheat breeding programs. Seven genotypes were moderately resistant against one or more of isolates. The other wheat genotypes were susceptible to isolates tested. The five isolates studied in this study had varying degrees of virulence and invasion on wheat genotypes, which indicates difference in avirulence genes of this pathogen. The isolate BK94 was the most virulent and invasive isolate on wheat genotypes, and the isolate BK56 had the least virulence and invasion.