THE RYE MILDEW FUNGUS CARRIES AVIRULENCE GENES CORRESPONDING TO WHEAT GENES FOR RESISTANCE TO RACES OF THE WHEAT MILDEW FUNGUS

The common wheat cultivar Chancellor and its near-isogenic lines carrying resistance genes to Blumeria graminis f. sp. tritici, the wheat powdery mildew fungus, were inoculated with 60 F-1 cultures derived from a cross between B. graminis f, sp, secalis, the rye powdery mildew fungus, and B. graminis f. sp. tritici. Segregation patterns of avirulent and virulent cultures showed that the F-1 population carries avirulence genes corresponding to Pml, Pm2, Pm3a, Pm3b, Pm3c, and Pmla, resistance genes to races of the wheat mildew fungus. This result indicates that the rye mildew fungus, an inappropriate forma specialis for wheat, carries these avirulence genes.