Abstract: The gene effects, combining abilities of resistance to powdery mildew in common wheat were investigated in this study on a 6x6 diallel crossing design. The results showed that the disease index of powdery mildew in wheat was of quantitative character inheritance, which fitted the additive-dominant model. Therefore, it was controlled simultaneously by both additive and dominant gene effects, the former of which had the preponderance over the latter. As to the dominant gene effects, the low disease index showed partial dominance. There was remarkable difference among the parents examined in GCA effects and the number of favourable dominant genes. To obtain desirabls combinations, attention should be paid to the evaluation of SCA on the basis of GCA of the parents. The results of this experimnt also showed that pero-xidase(POD) activity in susceptible cultivars was higher than that in resistant ones.

Key words: Common wheat, Powdery mildew, Combining ability, Peroxidase