Grey correlation analysis of morphological traits related to drought tolerance of wheat at the seedling stage.

This paper aims at probing the relationship between morphological traits and drought tolerance of wheat cultivars and screening effective indexes for drought resistance.A total of 9 morphological traits including plant height,main root length,root number,shoot fresh weight,shoot dry weight,root fresh weight,root dry weight,leaf number,root/shoot ratio measured in 28 wheat cultivars grown at laboratory drought stress by PEG-6000,were analyzed using grey relational grade.At the same time,cultivars were classified by using clustering analysis base on weight drought-tolerance coefficient.Grey correlation degrees were calculated between each trait and its drought coefficient and ranked as follows: leaf number(0.817) plant height(0.766) shoot dry weight(0.746) shoot fresh weight(0.729) root number(0.699) root dry weight(0.688) root fresh weight(0.681) root/shoot ratio(0.645) main root length(0.399).The result showed that 9 morphological traits could be classified 3 categories.The cluster consequence reflected fundamentally the origin and area distribution of cultivars.The results suggested that the over-ground traits was the base and the root traits were second in the trait-based selection of drought tolerance to improve the screen efficiency.