Abstract: Effect of high density and high nitrogen fertilizer on resistance to powdery mildew and yield traits of south regional testing barley cultivars was studied. The main results showed as follows: disease severity and disease index of powdery mildew significantly increased at the 0.01 level under high density and high nitrogen fertilizer, while total disease incidence was not significantly affected. As far as yield traits were concerned, 1 000grain weight, panicle length, yield and grain yield per panicle significantly decreased at the 0.05 and 0.01 level; plant height significantly increased at the 0.01 level; panicle number and seed setting rate were not significantly affected. There was great difference in the powdery mildew resistance of barley cultivars under high density and high nitrogen fertilizer, and one was resistant, the other one was sensitive to powdery mildew.

Key words: barley, high density and high nitrogen fertilizer, resistance to powdery mildew, yield traits