Analyses of the results of 21 winter wheat and 32 spring barley trials showed that cultivars differed significantly in their yield response to a standard fungicide treatment. Responses were also strongly influenced by differences between sites and between years. Regression analyses showed that responses were significantly related to reductions in foliar disease, particularly that of mildew, although the proportion of variance accounted for was small. Measurements made on seven winter wheat trials indicated that the percentage of leaf area remaining green after anthesis was increased by the fungicide treatment to a greater extent than could be attributed to reduction in foliar disease alone. In one of these trials, yield response was more closely correlated with the increase in leaf area remaining green than with reduction in foliar disease.

No abstract

The results of 21 winter wheat and 32 spring barley trials done in the United Kingdom showed that cultivars differed significantly in their yield response to a standard fungicide treatment. Regression analyses showed that yield responses were significantly related to disease reduction, particularly that of mildew, although the proportion of variance accounted for was small. Measurements made on seven winter wheat trials indicated that the percentage of leaf area remaining green after anthesis was increased by the fungicide treatment to a greater extent than could be attributed to disease reduction alone. In some of these trials, yield responses were more closely correlated with the increase in leaf area remaining green than with disease reduction.

No abstract

SUMMARYThe Wycombe seedling method for measuring the susceptibility of wheat cultivars to physiologic races of Puccinia striiformis involves determining the percentage of seedlings bearing uredosori at a fixed time after inoculation under controlled environment conditions. Each cultivar is classified statistically as either vertically or horizontally susceptible and this classification is utilized in expressing the susceptibility of each to a number of races as a single value.The method has been used for three years to evaluate wheat cultivars and examples of significant differences in susceptibility between cultivars are given.A highly significant correlation has been established between data collected using the Wycombe seedling method and field data from physiologic race test beds.