Identification of resistance genes against Erysiphe graminis tritici in Indian and exotic wheats

Powdery mildew resistance genes were postulated in 82 Indian and exotic wheat genotypes using infection-type matching technique. The genotypes were subjected to eight pathotypes of Erysiphe graminis f. sp. tritici with diverse virulence. Based on their reaction to the pathotypes, the genotypes were categorised into 8 groups (I to VIII). Resistance in first VI groups was govemed by genes Pm3a, Pm3c, pm5, Pm8 and some unidentified gene(s) individually or in combination. In majority of the genotypes resistance was attributed to gene Pm8 individually or in combination with other gene(s). Presence of gene Pm8 was confirmed by pedigree relationships. Sixteen genotypes in group VII behaved differentially to the pathotypesi however, resistance in these genotypes could not be attributed to any known gene(s). Twenty two genotypes in group VIII showed susceptible reaction to all the pathotypes indicating absence of resistance gene(s).