Genetic diversity analysis and germplasm identification of ‘ShiqianTaicha’ (Camellia sinensis var. sinensis) resources based on morphological traits and biochemical components

‘ShiqianTaicha’ is a historically famous tea, and was an important local populationvariety and has rich germplasm resources. To systematically evaluate the ‘ShiqianTaicha’ resources and identify excellent resources, we analyzed the morphological traits and biochemical components of 52 tea resources. The morphological traits and biochemical components of ‘ShiqianTaicha’ tea germplasm resources exhibit high genetic diversity. The coefficients of variation (CVs) of morphological traits of ‘Shiqian Taicha’ ranged from 7.95–45.67%, with an average of 28.37%, while H' ranged from 0.37 to 2.06, with an average of 1.02; the CVs of biochemical components ranged from 3.73–54.05%, with an average of 20.35%, while H' ranged from 1.21 to 2.09, with an average value of 1.86. Significant positive and negative correlations were observed between the morphological traits and biochemical components. PCA revealed that the total contribution rate of 14 traits, including leaf length, leaf width, leaf area, leaf tooth acuity, bud leaf color, water extract, tea polyphenols, total catechin and EGCG, was 81.05%, and these were the main factors influencing differences in tea tree resource morphological traits and biochemical components. Cluster analysis grouped the morphological traits and biochemical components into three main clusters and four main clusters, respectively.Based on the biochemical components, 25 resources with high levels of EGCG (≥ 10%), 2 resources with high levels of tea polyphenols (≥ 25%) and 4 resources with high levels of catechin (≥ 20%) were selected as excellent resources. These resources have the potential to be utilized in the cultivation of specific tea tree varieties with regional characteristics.