Abstract:Twelve representative soybean varieties were used for the evaluation of drought resistance under two given treatments (drought stress and normal irrigation) in Dunhuang City (Gansu Province) with an annual rainfull below 40mm in 2014 and 2015. Two evaluation methods, an improved drought index evaluation and a weight subordinate function evaluation (D value) were applied to the evaluation using eight morphological traits (plant height, number of main stem nodes, branch number, pod number per plant, seed number per plant, yield per plant, biomass per plant and 100-seed weight) and plot yield. Three different drought-resistant type soybean varieties were detected for six physiological indexes of SOD (superoxide dismutase), POD (peroxide), CAT (catalase) activities, and MDA (malondialdehyde) content, Pro (proline) content and SS (soluble sugar) content to validate the evaluation methods and the suitability of the physiological indexes as indicators of drought resistance. The results showed that six morphological traits and plot yield except branch number per plant and 100-seed weight in 2014 and all the traits in 2015 reached significant differences in drought stress treatment against the irrigation treatment (CK). The weight subordinate function evaluation highly coincided, with a significant correlation among varieties and plot yield showed an extremely significant correlation with the index values of the two evaluation methods between the two years. Six physiological indexes showed that under two treatments conditions, the three different drought-resistant type varieties had larger differences in these indexes among varieties, and also week drought-resistant WDD00172 and moderate drought-resistant Zhonghuang No. 24 had extremely significant differences between the both treatments of drought stress and normal irrigation in all the physiological indexes, whereas high drought-resistant Jindou No. 21 did not, which appeared to suggest that although the activities or contents of the six physiological indexes were significantly correlated with the weight subordinate function evaluation of week and moderate drought-resistant varieties, they were not correlated with the weight subordinate function evaluation of high drought-resistant varieties. Therefore, the results obtained in this work strongly suggest that the weight subordinate function evaluation can be used as an effective method and plot yield as a reliable index in drought resistance evaluation.