Abstract: The genetic diversity of tea germplasm in China is an important basis for its effective utilization. In this study, the genetic diversity of tea germplasm in China was elucidated by statistical analysis, principal component analysis, correlation analysis and cluster analysis of 18 image features of mature leaves from 504 tea germplasm accessions preserved in China National Germplasm Hangzhou Tea Repository. The results show that the coefficient of variation and genetic diversity index of this population were 15.97% and 1.98, respectively. Among different provinces, the average coefficient of variation was the largest in Fujian province, which was 16.29%. The data of Jiangsu province was on the bottom, accounting for 10.58%. Zhejiang province had the highest average genetic diversity index at 2.01. The average genetic diversity index of Chongqing municipality reached the lowest point, occupying 1.67. The dimension of 18 image features were streamlined by principal component analysis and characterized into 4 principal components, with a cumulative contribution rate of 82.63%, and 12 image features were screened out from 18 image features with significant differences. According to the image features, the tea germplasms were clustered into 6 groups. The results provided a theoretical basis and reference for further exploration and utilization of tea germplasm in China.

Key words: tea plant, germplasm, mature leaves, genetic diversity, image characteristics