The Correlation of Drought-Resistance Evaluation between Agronomic Traits and Physiological Indexes of Wild and Cultivated Soybean

Wild,semi-wild and cultivated soybeans were used as materials to study the evaluation system of drought resistance identification of soybean. The drought stress treatment was conducted at seedling and flowering stage under pot experiment condition. The method of subordinate function was used to comprehensive analyze the correlation of drought resistance and agronomic traits and physiological indexes. The result showed that the reaction of different types of soybeans were the same no matter in seedling or flowering stage. The comprehensive membership function values of morphological indexes and physiological indexes had significant positive correlation under the drought stress condition. The drought resistance results of soybeans were highly consistent assessed by the two indicator systems. Morphological indexes for pods per plant,plant grains and plant grain weight associated with drought resistance more closely among the agronomic traits. The physiological response of soybean to drought stress was different in seedling stage and flowering phase. The physiological indexes closely associated with drought resistance were the soluble sugar content and CAT activity in seedling stage,but it were the soluble sugar content and chlorophyll content in flowering phase. Soluble sugar content is the reliable physiological index of drought resistance of soybean.