Comparison of Evaluation Methods for Drought-Resistance at Soybean Adult Stage

Drought is a very important abiotic stress for soybean production in China. A number of methods have been used to evaluate drought tolerance of In this study, 77 soybean varieties or lines with Jindou 21 as the control were planted under both conditions of drought stress and normal irrigation in Dunhuang City, Gansu province, where the annual rainfall is less than 40 mm. The identification criteria for drought-resistance were selected from eight yield-related agronomic traits, and different evaluation methods were compared by simple correlation, spearman correlation, stepwise regression and gray correlation. The results showed that the evaluation method of drought resistance coefficient had the same effect as that of index of damage and drought resistance index. The comprehensive evaluation methods based on biomass, grain number per plant and pod number per plant had no advantages than the direct evaluation method based on yield. Drought resistance rather than high yield could be se-lected by traditional drought resistance coefficient method. The soybean varieties with drought resistance and stable yield under both drought and normal conditions could be selected using the improved drought resistance index created in this study, such as Xudou 12, Zhongzuo 00-683, and Zhonghuang 24, which could be used for soybean production in drought stress area. We might select drought resistant soybean varieties based on their maturity groups. This study provided a theoretical basis for evaluating drought resistant soybean germplasm and for establishing the standard evaluation system for drought resistant soybean.