| After the application of herbicides on wheat, if encountering cold weather or low temperature below 0 ℃ in a short time, it is easy to cause herbicide-induced frost damage, which poses a serious threat to the production of wheat. To date, no study of indices for the identification and evaluation of wheat resistance to herbicide-induced frost damage was reported. In order to figure out the identification indices, 15 000 wheat germplasms were preliminarily evaluated, and 20 representative germplasms from different wheat regions in China were used to investigate their resistance to herbicide-induced frost damage under different conditions including seedling age for herbicide application, low temperature treatment time after herbicide, low temperature level and duration, soil moisture, and investigation time. The results showed that under the conditions of herbicide application at 3-leaf stage, 3 days’ growth after herbicide, subsequent 5 days’ growth at -4 ℃, and suitable moisture content (water content of 15%—18%), the coefficient of variation and the numerical dispersion of the relative index among the tested materials were the largest, and the significance level of differences was also the highest, which clearly distinguished their resistance to herbicide-induced frost damage of the tested germplasms. Therefore, this study proposed evaluation indices for identifying the resistance of wheat to herbicide-induced frost damage. According to the change range of relative herbicide-induced frost damage index, the characteristics of resistance to herbicide-induced frost damage in wheat were divided into five types, namely highly resistant (≤ 0.10), resistant (0.11—0.30), moderately resistant (0.31—0.50), susceptible (0.51—0.70), and highly susceptible (> 0.70). The establishment of this method will provide reliable technical basis for screening wheat germplasms resistant to herbicide-induced frost damage and breeding resistant varieties. |
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