Diversity and correlation analysis of phenotypic traits in Camellia yungkiangensis H. T. Chang germplasm resources

【Objective】The morphological characteristics genetic diversity and the correlations of Rongjiang tea（Camellia yungkiangensis H. T. Chang），an exotic tea resource in Guizhou，were analyzed. It would not only lay the foundation for future in-depth research on the origin and evolution of this resource，but also provide reference for its excellent gene mining，innovative utilization and conservation.【Method】In this study，118 C. yungkiangensis germplasm resources were used to determine 19 phenotypic traits. Through analyzing their genetic variation，correlation，principal components and clustering，their genetic diversity and affinities could be studied.【Result】The plant shapes under study were mostly upright or semi-open，the plant types were mostly shrubs，and the leaf characteristics were mainly medium leaf types with green leaf color，acuminate leaf tip，cuneate leaf base，spreading leaf body，smooth leaf surface，spreading leaf edge，hard leaf texture，medium density of leaf teeth，and shallow depth of leaf teeth. The values of diversity index for 13 qualitative traits ranged from 0.33 to 1.07 with an average of 0.66，and the coefficient of variation ranged from 20.06% to 66.83% with an average of 40.56%；the values of diversity index for 6 quantitative traits were 1.74-2.09 with an average of 2.00，and the coefficient of variation ranged from 8.20% to 23.92% with an average of 14.37%. The results of correlation analysis of 19 morphological traits of the study subjects showed that 14 pairs of traits were highly significantly positively correlated，10 pairs were significantly positively correlated，4 pairs were highly significantly negatively correlated，and 9 pairs were significantly negatively correlated. Principal component analysis showed that the first 7 principal components had eigenvalues greater than 1.000 and a cumulative contribution of 69.515%，containing most of the information of the original variables. The comprehensive scores of leaf phenotypic traits of each germplasm resource on each principal component were obtained by the factor score coefficient matrix，and 13 germplasm resources with high comprehensive leaf scores were selected. According to the cluster analysis，the 118 C. yungkiangensis germplasm resources could be divided into 7 clusters at the Euclidean distance of 17.5，with the Ⅰ cluster containing 83 resources；the Ⅱ cluster containing 5 resources；the Ⅲ cluster containing 4 resources；the Ⅳ cluster containing 12 resources；the Ⅴ cluster containing 6 resources；the Ⅵ cluster containing 7 resources；the Ⅶ cluster containing 1 resources.【Conclusion】 The germplasm resources of C. yungkiangensis are rich in genetic diversity and have great potential to be used in the selection and breeding of new tea varieties and germplasm innovation. The 13 germplasm resources with high comprehensive leaf scores can be used in variety breeding.