ZHAO Yufeng, ZHOU Qingyuan, GAO Huanhuan, YE Sang, WANG Qian, CHENG Chuang, GUO Yanjun, CUI Cui
In order to study the drought tolerance of vegetable pea seeds during germination period, 31 vegetable pea varieties were used as experimental materials and were treated with 2.5% PEG-6000 solution to simulate drought stress. The seed germination energy (GE) and germination rate (GR) were counted, and fresh weight (FW), dry weight (DW), root length (RL), buds length (BL) and storage material transfer rate (STR) were measured. Then, correlation analysis, principal component analysis, cluster analysis, grey correlation analysis and stepwise regression analysis were used to identify drought tolerance and screen drought tolerance index of 31 vegetable pea varieties during seeds germination stage. The results showed that 2.5% PEG had significant effect on indexes measured during germination of vegetable pea. The germplasm were sorted according to the comprehensive drought resistance coefficient value (CDC), drought tolerance evaluation value (D) and weighted drought tolerance coefficient value (WDC). As a result, there were 4 varieties including 16110, 16055, 16140 and 16107 showed stronger drought tolerance while 3 varieties including 16106,16175 and 16177 showed drought sensitivity. By cluster analysis, 31 pea germplasm can be divided into 4 group at Euclidean distance D2=8.5, in which the first group includes 20 varieties such as 16054, 16142, 16138 and so on, the second group includes 16140, 16079 and 16055, the third group contains 6 varieties, such as 16175,16104 and etc, and the fourth group contains 16110 and 16107. Also, stepwise regression analysis showed that the indexes closely related to D value were germination index, vigor index, germination potential and root length, which could be used as indicators of drought tolerance of pea germplasm resources during germination period. The results provide a theoretical reference for further study on drought tolerance mechanism and drought mitigation mechanism of vegetable pea during germination, and laid a foundation for breeding and popularizing the drought-tolerant varieties of vegetable pea.