Operation of resistance genes in wheat to Erysiphe graminis f.sp. tritici against E. graminis f.sp. agropyri
The common wheat cultivar 'Chancellor' and its near-isogenic lines carrying resistance genes to Erysiphe graminis f.sp. tritici were inoculated with 240 F1 cultures derived from a cross between E. graminis f.sp. agropyri, Ak-1, and E. graminis f.sp. tritici, Tk-1. Segregation patterns of avirulent and virulent cultures suggested that the F1 population carries avirulence genes corresponding to Pm1, Pm2, Pm3a, and Pm3b. These avirulence genes were considered to be derived from Ak-1. It was therefore concluded that Pm1, Pm2, Pm3a, and Pm3b, resistance genes to E. graminis f.sp. tritici, operate against E. graminis f.sp. agropyri.Key words: powdery mildew, Erysiphe graminis, resistance, wheat, wheatgrass.