Use of Multiple Regression to Examine the Effect of Leaf Rust and Yellow Spot on Yield of Wheat in Northern New South Wales

In trials with 5 recommended cultivars considerable yield losses were recorded from comparatively low levels of infection. Yellow spot (Pyrenophora tritici-repentis) was associated with losses of 13 and 21% in the leaf rust (Puccinia recondita) resistant cultivars Banks and Durati, respectively. Leaf rust was associated with a loss of 15% in Kite which has moderate resistance to yellow spot. The combined effects of both diseases reduced yields of Cook by 36% and of Songlen by 7%. The yield losses of Banks and Kite were associated with reduced kernel size while that of Durati was related to reduced number of kernels. Yield loss in Cook was related to reduced size and number of kernels. These results indicate that a model of yield loss based on disease level of the crop is potentially superior to one based on disease on single tillers. Resistance to P. recondita and P. tritici-repentis is a desirable character in wheats being bred for this area. Australasian Plant Pathology 14(4) 62 - 64 Full text doi:10.1071/APP9850062 © CSIRO 1985