Evaluation of drought resistance and index screening of foxtail millet cultivars

Screening for identification indicators and establishing a drought-resistance evaluation system can provide a basis for the selection and layout of drought-resistant foxtail millet cultivars. Twenty-one main foxtail millet cultivars in China were evaluated for the drought resistance by measuring their main agronomic traits and photosynthetic indicators under the condition of drought stress and normal irrigation. Identifying the drought resistance is difficult when using a single index. The order of drought resistance of tested foxtail millet cultivars based on drought resistance comprehensive evaluation values (D value) and drought resistance index (DRI value) differed to an extent; therefore, a comprehensive evaluation method combining D and DRI values was appropriate and accurate. Gray correlation analysis showed that the grain weight per ear, yield, ear weight, and ear length could be used as indicators for drought-resistance evaluation of foxtail millet cultivars at the mature stage. According to the clustering analysis based on D and DRI values, the tested cultivars were divided into three grades of drought resistance and six foxtail millet cultivars with strong drought resistance were identified. The photosynthetic indicators showed that the net photosynthetic and transpiration rates and D and DRI values had correlation coefficients greater than 0.320.