66份云南茶树种质生化成分的分析及特异种质筛选

【目的】鉴定云南茶树种质资源，分析其儿茶素和嘌呤生物碱的多样性，筛选出高儿茶素指数（Catechin index，CI）、高苦茶碱等特异茶树种质资源，为茶树品种选育和特异产品开发提供科学依据。【方法】通过高效液相色谱（HPLC）检测云南66份代表性茶树种质的儿茶素[没食子儿茶素（GC）、表没食子儿茶素（EGC）、儿茶素（C）、表儿茶素（EC）、表没食子儿茶素没食子酸酯（EGCG）、没食子儿茶素没食子酸酯（GCG）、表儿茶素没食子酸酯（ECG）]和嘌呤生物碱（咖啡碱、可可碱和苦茶碱）等主要品质和功能性成分；利用统计软件分析其遗传多样性（香农多样性指数，H'），并对其进行主成分分析和聚类分析；最后筛选出高CI、高苦茶碱的种质。【结果】66份云南茶树种质的GC、EGC、C、EC、EGCG、GCG、ECG、咖啡碱和可可碱等成分存在丰富的遗传多样性和变异性，其中，H'除EC、ECG外均大于1.80，EGCG的H'最高（2.06）；C（66.07%）具有最大的变异系数，可可碱的变异系数（15.68%）最小。通过主成分分析，发现前5个主成分的累计方差贡献率达83.37%，包含所有性状的大部分信息。基于14个生化成分，可以将66份茶树种质分为4个类群，不同类群在CI、可可碱、咖啡碱、儿茶素总量等主要指标有明显差异。综合分析结果，筛选到13份CI > 0.60的茶树种质，其中有4份大于0.90（2份大于1.00）；另外，还鉴定到4份（其中有3份还具有低咖啡碱性状）高苦茶碱茶树种质。【结论】云南省茶树资源的儿茶素和嘌呤生物碱多样性丰富，变异系数大，具有丰富的遗传多样性；筛选到高CI、高苦茶碱、低咖啡碱等特异种质17份。

Biochemical component analysis and specific resource selection of 66 accessions of tea germplasms in Yunnan

【Objective】The genetic diversity of catechins and purine alkaloids of tea germplasms in Yunnan were identified. Afterwards, the specific tea genetic resources with high catechin index(CI) values and high theacrine content were screened according to the results, which provide scientific bases for tea breeding and product development.【Method】The predominant components of 66 representative tea germplasms in Yunnan, including catechins[(+) -gallocatechin(GC), (-) -epigallocatechin(EGC), (+) -catechin(C), (-) -epicatechin(EC), (-) -epigallocatechin-3-gallate(EGCG), (-) -gallocatechin-3-gallate(GCG), (-) -epicatechin-3-gallate(ECG)], purine alkaloids(caffeine, theobromine, and theacrine), were detected by high efficiency liquid chromatography(HPLC). Their genetic diversity(Shannon's diversity index, H') were performed by statistical software, principal component and cluster analysis were conducted. And the resources with high CI value and high theacrine were selected from the 66 accessions of tea germplasms.【Result】There were abundant genetic diversity and variability of GC, EGC, C, EC, EGCG, GCG, ECG, caffeine, theobromine in 66 Yunnan tea germplasms. Among them, the genetic diversity index of EGCG was the highest(2.06). Furthermore, the other components were greater than 1.8 except for EC and ECG. C had the largest coefficient of variation(66.07%), while theobromine had the smallest coefficient of variation(15.68%). Principal component analysis revealed that the cumulative contribution rate of the first five principal components presented the most of trait information as it reached 83.37%. Based on 14 biochemical components, 66 accessions of tea germplasms could be divided into four groups. And each groups had different main indicators such as CI value, theobromine, caffeine, and total catechins. A total of 13 tea germplasms with CI value greater than 0.60 were screened according to comprehensive analysis results, of which four were greater than 0.90(including two were more than 1.00);in addition, four tea germplasms with high theacrine(including three resources with low caffeine) were also identified.【Conclusion】Tea germplasms in Yunnan contain large variability of catechins and purine alkaloids, large variation coefficient. Therefore, they possess abundant genetic diversity. More importantly, 17 specific tea resources such as with high CI values, high theacrine, and low caffeine are selected.