Inheritance of Resistance to Powdery Mildew (Erysiphe graminis f. sp. hordei) in Barley

Two barley (Hordeun vulgare L.) genotypes, Radical and Cwb, with good to moderate levels of resistance to powdery mildew were crossed with a highly susceptible cultivar (Afzal) to determine the genetics of resistance. The parents, Fl, F2 and F3 generations of each of the two crosses, were evaluated for powdery mildew resistance in the glasshouse and field at the College of Agriculture in Karaj during 2000. The x2 analysis of the segregating ratios in the F3 generations indicated that the resistance was controlled by one gene at seedling stage and by two or three genes at adult plant stage in Cwb and Radical, respectively. Radical showed a higher level of resistance than the Cwb, therefore, it is a better source of resistance to powdery mildew