YIELD LOSSES IN WHEAT CAUSED BY STRIPE RUST (PUCCINIA-STRIIFORMIS WEST) IN NORTHERN NEW-SOUTH-WALES

Three field trials were established at Tamworth in northern New South Wales to quantify the effect of stripe rust on the yield of wheat. The yield parameters were total grain yield per plot, 1000-grain weight, number of grain produced per head. tiller number and grain yield per plant. In addition, grain protein and dough and flour quality were determined. The total yield losses were found to be dependent on the cultivar, the timing of the epidemic and the yield potential of the crop. In most cases, early stripe rust epidemics had a greater effect on yield than late epidemics. Total grain yield and 1000-grain weight were most often affected. Long season epidemics affected all the yield parameters, with losses of up to 50% in grain yield being recorded in susceptible cultivars. The quality of dough and flour was unaffected by the fungicide treatments. The results suggest that the levels of resistance of the currently recommended wheat cultivars were sufficient to protect them from yield losses from stripe rust epidemics in most years. © 1990 CSIRO. All rights reserved.