基于表型性状和生化成分的贵州乔木型茶树种质资源遗传多样性研究

Genetic Diversity of Guizhou Arboreous Tea Plants based on Phenotypic Traits and Biochemical Components

以贵州9个县(市)195份乔木型茶树种质资源为研究对象,通过表型性状及生化成分分析,探究其遗传多样性。结果表明:16个描述型表型性状变异系数为0~44.00%,平均27.33%,多样性指数为0.19~0.99之间,平均0.67;5个数值型表型性状的变异系数为12.17%~33.37%,平均20.75%,遗传多样性指数为4.36~4.91,平均4.64。不同数值型表型性状变异系数差异较大,遗传多样性指数差异较小。基于形态学性状聚类分析,可将195份乔木型茶树资源聚为3个类群,发现第Ⅰ类群为中小叶类,第Ⅱ类群和第Ⅲ类群为中大叶类,除叶片大小外,3个类群的描述型表型性状较为复杂,没有明显的特征性状。茶多酚含量为10.93%~21.35%,茶氨酸含量为0~3.19%,咖啡碱含量为0.07%~5.32%,苦茶碱含量为0~2.87%,EGCG含量为0~10.87%。同时从195份乔木型茶树资源中筛选出74份特异种质资源,包括低咖啡碱资源35份,高咖啡碱资源2份,高ECG资源5份,高EGCG资源6份,高EGC资源26份,其中35份低咖啡碱资源全部来自盘州市,同时这35份资源检测出苦茶碱。遗传多样性指数在1.15~4.01之间,平均为2.90,表现出丰富的遗传多样性,保持着较高的遗传多样性水平。各个县(市)茶树种质资源间变异系数为13.91%~211.84%,变异幅度较大。基于主要生化成分聚类分析,可将195份乔木型茶树资源聚为3类,发现第Ⅰ类以苦茶碱为主要生物碱,而第Ⅱ类和第Ⅲ类中不含苦茶碱,以咖啡碱为主要生物碱。

Using 195 arboreous tea germplasm resources from 9 counties(cities)in Guizhou as the materials,the genetic diversity was explored through phenotypic traits and biochemical component analysis.The results show that the coefficient of variation of 16 descriptive phenotypic traits ranged from 0 to 44.00%,with an average of 27.33%.The diversity index ranged from 0.19 to 0.99,with an average of 0.67.The coefficient of variation of the five numerical phenotypic traits ranged from 12.17%to 33.37%,with an average of 20.75%.The genetic diversity index ranged from 4.36 to 4.91,with an average of 4.64.The coefficient of variation of phenotypic traits varied greatly among different numerical types,while the difference in genetic diversity index was relatively small.Based on morphological trait clustering analysis,195 arboreous tea germplasms could be clustered into three groups.It was found that the first group had small and medium-sized leaves,while the second and third groups had medium and large leaves.Except for leaf size,the descriptive phenotypic traits of the three groups were relatively complex without obvious characteristics.The contents of tea polyphenols,theanine,caffeine,theacrine,EGCG were 10.93%-21.35%,0-3.19%,0.07%-5.32%,0-2.87%and 0-10.87%,respectively.Meanwhile,74 specific germplasm resources were selected from 195 arboreous tea germplasms,including 35 low caffeine resources,2 high coffee resources,5 high ECG resources,6 high EGCG resources,and 26 high EGC resources.All 35 low caffeine resources were from Panzhou City,and the content of theacrine was detected in these 35 resources.The genetic diversity index H′ranged from 1.15 to 4.01,with an average of 2.94,demonstrating a highrich genetic diversity and maintaining a high level of genetic diversity.The coefficient of variation in each county(city)ranges ranged from13.91%to 211.84%,with a significant range of variation.Based on the clustering analysis of main biochemical components,195 arboreous tea germplasms can could also be clustered into 3 categories.It was found that in the first category,theacrine isbitter theophylline is the main alkaloid,while high caffeine but no theacrine were identified in the second and third categories,bitter theophylline is not present,and caffeine is the main alkaloid.