Drought can seriously affect the growth of plants.In order to cope with the impact of drought on vegetable production,breeding and popularizing drought-tolerance and drought-resistance varieties is an important strategy.20 different varieties of Cucurbita moschata seedlings were subjected to drought stress treatment by using hypertonic solution of 20%PEG-6000.Stem diameter,plant height,plant dry weight,aboveground dry weight,root dry weight,plant fresh weight,aboveground fresh weight,root fresh weight,number of real leaves,real leaf length,real leaf width,relative chlorophyll content(SPAD value)of leaves and drought index were measured,and drought resistance was comprehensively evaluated by using correlation analysis,difference analysis and cluster analysis.The results showed that the indexes of stem diameter,plant dry weight,aboveground dry weight,root dry weight,plant fresh weight,aboveground fresh weight,root fresh weight,real leaf length and real leaf width of'Dianxiheizuan'variety were all the largest,which were 0.68 cm,6.15 g,3.04 g,3.11 g,7.18 g,3.55 g,3.64 g,4.34 cm and 5.34 cm,respectively,and indicators of plant dry weight,aboveground dry weight,root dry weight,plant fresh weight and aboveground fresh weight showed significant differences compared with other varieties,respectively.The variation coefficients of two indicators of the real leaves number and SPAD value were the smallest,both were 10%,while the variation coefficient of root fresh weight was the largest with 53%.The correlation coefficient between plant dry weight and root dry weight was the largest(0.965).The first variety of comprehensive membership function value was'Dianxiheizuan',which has the best drought resistance,followed by the'Caiyunjingxuan'variety with the second drought resistance.The tested varieties were divided into five categories by cluster analysis,and'Dianxiheizuan'was in group 1,which was the most drought resistant variety,'Caiyunjingxuan'was in group 2,and other varieties had weaker drought resistance and were clustered into the other three groups,respectively.In this experiment,two varieties with good drought resistance were screened out,including'Dianxiheizuan'and'Caiyunjingxuan',which provided materials for the follow-up drought resistance breeding of Cucurbita moschata,and provided reference for the research of drought resistance during the seedling stage.
Cucurbita moschataseedling stagegermplasm resourcemembership function methoddrought-resistance breedingstress resistance evaluation