Effectiveness of Resistance Genes to Septoria tritici Blotch (Stb) in Differential Cultivares of Wheat against Zymoseptoria tritici Isolates

Abstract Septoria leaf blotch (STB) disease, caused by Zymoseptoria tritici, is one of the most important diseases of wheat in all over the world and Iran. Genetic resistance is the most important and economical strategy to control this disease. Continuous monitoring of the fungus populations is indispensable to study the efficiency of Stb resistant genes. In this study, virulence pattern of five different isolates on differential cultivars of wheat with resistance genes and the effectiveness of these genes against isolates were studied at seedling stage under greenhouse conditions. The results showed that BK94 and BK56 were the most and the least virulent isolates on differential cultivars, respectively. M3 and Arina were resistant to all isolates. TE9111, Riband and Flame were resistant to three, two and two isolates, respectively. The other differential cultivars were susceptible against the tested isolates. Among the Stb genes, Stb15, Stb16 and Stb17 were the most effective resistance genes to all isolates, therefore they can be used as resistance sources to STB in breeding programs in Iran.