Analysis of quality components and diversity of ten cultivars of introduced tea plants in the Gannan tea area

【Objective】 This study aimed to analyze quality components and diversity of ten cultivars of introduced tea plants in Gannan tea area of Jiangxi Province， and to provide references for introducing suitable tea cultivars for produ-cing Gougunao tea and breeding new tea cultivars in the Gannan tea area.【Method】 Fresh leaves of ten cultivars of tea plants introduced to the Gannan tea area were taken as materials， and Fuding Dabaicha was taken as the control to observe their phenological phases. Quality components of samples in the ten cultivars were also determined. Principal component analysis and cluster analysis were used to evaluate their quality components， genetic diversity， and suitability.【Result】 Phenological observation indicated that Huangjincha No. 1 was classified as an extra-early sprouting cultivar， whereas Zhonghuang No. 3 and Zhongcha 108 were early-sprouting cultivars； while the phenological phases of the remaining seven tea cultivars showed minor differences compared to the control. The ten cultivars of introduced tea plants showed differences in contents of quality components： water of 3.98-8.81 g/100 g， water extract of 46.67%-53.83%， tea polyphenol of 19.70%-26.93%， total free amino acid of 2.50%-3.80%， caffeine of 1.90%-3.70%， and total catechin of 7.95%- 18.40%， epicatechin （EC） of 0.48%-1.12%， epicatechin gallate （ECG） of 1.27%-3.46%， epigallocatechin （EGC） of 0.47%-2.78%， epigallocatechin gallate （EGCG） of 4.90%-10.54%， catechin （C） of 0.16%-2.11%， ester catechin 6.17%- 14.00%， non-ester catechin 1.42%-4.40%， with the catechin quality index of 400.00-1526.15. Zhenong 117 showed eight highest indexes， including total catechin， water extract， tea polyphenol， ECG， EGCG， C， ester catechin， and non-ester catechin. The ten cultivars of introduced tea plants were resources of high water extracts， Zhenong 117 and Zhongcha 108 were resources of high catechin， and Yujinxiang were resources of low caffeine. For the ten cultivars of introduced tea plants， genetic diversity indexes ranged from 2.12-2.30 （mean of 2.26）， coefficients of variation 0.00%-57.19% （mean of 22.96%）， with the highest coefficient of variation found in C （57.19%）. Cluster analysis of the ten cultivars of introduced tea plants showed that： at the genetic distance of 7.5， they could be divided into two groups； the GroupⅠincluded six tea cultivars with higher contents of caffeine， total free amino acid， and total catechin and a lower catechin quality index； the Group Ⅱ included four tea cultivars with higher contents of water extract， tea polyphenol and catechin quality index and a lower EC content. Among the 15 indexes of principal component analysis， the first four were extracted as principal components， with their cumulative variance contribution rate of 95.68%. Among the ten cultivars of introduced tea plants， five varieties （Naibai tea， Yujinxiang， Zhonghuang No. 1， Zhonghuang No. 2， and Huangjingya） demonstrated suitability for green tea production； four cultivars （Zhenong 113， Huangjincha No. 1， Zhongcha 108， and Zhonghuang No. 3） exhibited suitability for both black and green tea production； while Zhenong 117 exhibited suitability for black tea production.【Conclusion】 The ten tea cultivars introduced to Gannan tea area enjoy rich chemical components， demonstrating high water extract content， and specific resources with high catechin and low caffeine are found among them， showing relatively high genetic diversity indexes and coefficients of variation. The ten cultivars of introduced tea plants exhibit considerable potential for further research and utilization in the development of specialty tea products and genetic improvement. Zhenong 117 shows potential suitability for producing Gougunao tea.