Abstract: Germplasm resources are the basis of genetic breeding research. Analyzing the genetic diversity of germplasm resources can provide a certain theoretical basis for parental selection. Genetic diversity, correlation, principal component and cluster analysis were performed on 11 phenotypic traits of 500 cotton germplasm resources materials. The results showed that the average coefficient of variation of the 11 traits was 9.69%. And there were 6 trait which coefficient exceeded 10.0%. The variation coefficient of the number of bells (20.14%) was maximum, and the variation coefficient of the fiber uniformity (1.81%) was minimum. The genetic diversity index of each trait was in the range of 1.71-2.06. The genetic diversity of boll number was highest and the genetic diversity index of growth period was lowest. Correlation analysis showed that there were different correlations between the various traits. Fiber length was significantly positively correlated with fiber uniformity, fiber strength and growth period but it was significantly negatively correlated with the micronaire value. The fiber strength was significantly positively correlated with the micronaire value and growth period. The lint percent was significantly positively correlated with the fiber length, fiber uniformity, and micronaire value but significantly negatively correlated with the seed index. The boll weight was significant positive correlated with lint percent, fiber length, fiber uniformity and growth period. By the principal component analysis, 5 principal components were extracted which cumulative contribution rate was 73.677%. The first principal component mainly related to fiber length, fiber strength, and fiber uniformity; the second was mainly related to the lint percent; the third was mainly related to the micronaire value; the fourth was mainly related to the number of fruit branches and the fifth was mainly related to the boll weight. Cluster analysis classified 500 cotton germplasm materials into four clusters at genetic distance 1.33. Cluster Ⅰ contained only one material, which character was high plant height, high boll weight, low lint percent, high seed index. Cluster Ⅱ contained 73 materials, which characters were few boll, low lint percent, and poor fiber quality. The Cluster Ⅲ contained 122 materials, which characters were high boll weight, high lint percent, long fiber and high fiber strength. Cluster Ⅳ contained 304 materials, which boll number, boll weight, lint percent, fiber length, and fiber strength were moderate.50 germplasm resources were extracted to construct the core collection. The variable coefficient and variance of each trait in core collection were higher than ones in the original population. Indicating that the core germplasm has better heterogeneity. The core collection heterogeneity was better than the original population. The core collection retains the genetic information of germplasm resources with the least number of resources, which not only reduces the workload of germplasm conservation, but also facilitates the selection of breeding parents.

Key words: Cotton, Core germplasm, Genetic diversity, Germplasm resources, Agronomic traits

CLC Number: 

• S562.03