Tolerances of wheat cultivars to post-emergence wild oat herbicides

Abstract

Sixteen spring wheat cultivars were tested in southern New South Wales for their tolerances to the recommended rates, and three times the recommended rates, and three times the recommended rates of barban, diclofop-methyl, difenzoquat and flamprop-methyl in 1978 and 1979. Differences between cultivars in their tolerances to barban and diclofop-methyl were identified in the grain yield responses to three times the recommended rates of these herbicides. Crop damage was more severe in 1978 than 1979. Olympic, Shortim, Teal and Warimba were consistently susceptible to barban, while Condor, Cook, Egret and Oxley were more tolerant than the other cultivars. The differences between cultivars treated with diclofop-methyl were smaller and variable. However, Lance, Teal and Tincurrin were the most sensitive whilst Cook, Kewell and Oxley showed the greatest tolerance. Visual assessments of crop damage did not accurately reflect crop tolerance, therefore grain yield should be used to identify susceptible cultivars.