Identification of new wheat common bunt pathotypes (Tilletia laevis Kuhn.)

Common bunt (CB) is the most important wheat disease after the rusts and the development of bunt-resistant cultivars is one of the best methods to control the disease. To identify new sources of resistance genes, identification of different pathotypes of this disease is essential. For this purpose, 449 isolates of CB collected from rainfed wheat fields in different regions of Kermanshah province, west of Iran were evaluated. Out of which, 417 isolates were identified as Tilletia laevis. According to the germination ability of the isolates, an isolate was chosen as the representative of the pathotypes collected from each region. Finally, 11 isolates were chosen for pathotype identification. The seeds of the differential sets were inoculated with these selected isolates and were cultivated in disinfected soil under field and glasshouse conditions. At the maturity stage the infection percentage on each differential genotype were recorded and according to the identification key, pathotypes L29, L10, L30, L31, L32, L20, L33, L34 and L3s were identified, of which only L10 and L20 were already known and the rest are newly evolved pathotypes. Virulence on M73-2154 with mixed genes Bt3,7,8 by L29 was observed for the first time.