The effect of powdery mildew (Erysiphe graminis f.sp. avenae) on yield, yield components and grain quality of spring oats

Yield components and grain quality were investigated on eight cultivars of spring oats with known differences in adult plant resistance to mildew and with different fungicide treatments. Losses in grain yield caused by mildew could be accounted for mainly by reductions in numbers of fertile panicles and thousand grain weights. The proportion of grain yield to total biomass, (harvest index) was also reduced. There were no effects of treatment on the concentration of fatty acids in the grain, the proportions of the component fatty acids, the percentage content of grain protein or the specific weights. However, correlation analysis of the data revealed that percentage protein contents and specific weights were negatively correlated with levels of mildew. There were significant genetic differences between cultivars in all of the yield and quality characteristics but no fungicide treatment/cultivar interactions.