Abstract: To clarify the genetic diversity of tea germplasm resources in Hunan Province, explore the genetic structure of germplasm resources for accurate identification and evaluation, genotyping by targeted sequencing (GBTS) was used to genotype and analyze the genetic diversity of 76 252 SNP loci in 78 tea germplasm resources in Hunan Province. A total of 30 agronomic traits and 15 biochemical components of this batch of resources were accurately identified. The results show that there was abundant genetic variation among 78 tea germplasm resources in Hunan Province, with a genetic diversity index of 0.07-2.08 for phenotypic traits and a coefficient of variation of 2.26%-47.50%. The smallest was the number of calyxs and the largest was the depth of leaf serration. The genetic diversity index of the biochemical components was 1.36-2.09, and the coefficient of variation was 5.90%-118.49%, with the smallest being water extract and the largest being gallic acid. When the Euclidean distance was 20, the 78 tea germplasm resources could be divided into five groups, and there were significant differences in leaf length, leaf size, leaf base shape, ratio of polyphenols/amino acids, GA, THEO, GC, EGC, EC, EGCG, GCG and ECG in groups Ⅰ and Ⅲ. Based on the genotype detection results of 78 resources, a phylogenetic tree was constructed, and 78 resources could be divided into three groups. At the same time, this study identified 23 tea resources with specific phenotypic traits, high levels of functional components such as amino acids, theobromine and caffeine. The results of this study could provide a basis for the protection and utilization of tea germplasm resources in Hunan.

Key words: tea plant, germplasm resources, accurate identification, genotyping by target sequencing (GBTS), genetic diversity