广西九万山茶树种质资源表型性状遗传多样性分析

Genetic diversity analysis of phenotypic traits of tea germplasm resources from Jiuwan Mountain, Guangxi

  • 摘要:目的】分析广西九万山茶树种质资源表型性状遗传多样性,为茶树起源进化研究、优异基因挖掘及种质创新利用与保护提供理论依据。【方法】以120份九万山茶树种质资源为材料,通过测定其树型、叶片等19个表型性状(包括13个质量性状和6个数量性状),通过遗传变异分析、相关分析、主成分分析及聚类分析对其主要表型性状及其遗传多样性进行系统评价。【结果】广西九万山茶树种质资源以灌木型(61.67%)和半乔木型(35.00%)为主;树姿以半披张居多(45.00%),直立(30.00%)和披张(25.00%)次之;叶片着生角度以平展为主(70.00%);叶色以绿色占比最高(74.17%),淡绿色次之(19.16%);叶尖以渐尖(38.33%)和急尖(36.67%)为主;叶基以楔形为主(74.17%);叶身以平展(57.50%)和内折(39.17%)为主;叶面以微隆(38.34%)和较平滑(30.00%)为主;叶缘以平展居多(87.50%);叶质以较柔软型和较脆型为主(各占34.17%);叶齿密度以中(55.84%)和密(38.33%)为主,叶齿深度以中(58.33%)和浅(25.00%)为主,叶齿锐度以锐(47.50%)和中(45.83%)为主。13个质量性状的平均Shannon-Wiener多样性指数(H')为1.31,变异系数为25.01%~45.07%;6个数量性状平均H'为2.03,变异系数为13.83%~38.63%。相关分析结果显示,11对性状呈极显著正相关,9对呈显著正相关,10对呈极显著负相关,10对呈显著负相关。主成分分析提取出前7个主成分,累计贡献率达67.29%,根据主成分得分筛选出5份叶片综合得分较高的优异种质。聚类分析结果显示,在欧式距离5.38处可将120份种质资源划分为七大类群,其中第Ⅰ、Ⅱ类群种质较多,合计占比75.83%;第Ⅴ类群的LZ099、LZ110及第Ⅲ类群的LZ034、LZ081因具有大叶、重芽等优良特性,可作为茶树育种的重要材料加以利用。【结论】广西九万山茶树种质资源的表型性状遗传多样性丰富,在茶树特异性新品种选育及种质创新方面具有良好的开发潜力,需进一步强化稀有类群的保护及核心种质挖掘与利用工作。

     

    Abstract:Objective】This study aimed to analyze the genetic diversity of phenotypic traits of tea germplasm resources from Jiuwan Mountain, Guangxi, providing theoretical reference for tea origin and evolution studies, superior gene mining, and germplasm innovative utilization and conservation.【Method】A total of 120 tea germplasm resources from Jiuwan Mountain, Guangxi were taken as research materials. A total of 19 phenotypic traits of them (including 13 qualitative traits and six quantitative traits) such as tree architecture and leaf morphology were determined, and genetic variation analysis, correlation analysis, principal component analysis, and cluster analysis were performed to systematically evaluate the major phenotypic traits and their genetic diversity.【Result】Most tea germplasm resources from Jiuwan Mountain, Guangxi, were shrubs (61.67%) and semi-arbors (35.00%); semi-spreading type accounted for the largest proportion (45.00%), followed by erect type (30.00%) and spreading type (25.00%). Leaf insertion angle was mainly flat type (70.00%). Leaf color was dominated by green (74.17%), followed by light green (19.16%). Leaf apexes were mainly acuminate (38.33%) and acute (36.67%). Leaf bases were mostly cuneate (74.17%). Leaf blades were mainly flat (57.50%) and involute (39.17%). Leaf surfaces were mainly slightly convex (38.34%) and relatively smooth (30.00%). Leaf margins were mainly flat (87.50%). Leaf texture was relatively soft or brittle (each accounting for 34.17%). Leaf serration density were mostly moderately (55.84%) and intensely (38.33%) dense; leaf serration depth was moderate (58.33%) or shallow (25.00%); leaf serration sharpness was mainly sharp (47.50%) or moderately sharp (45.83%). The average Shannon-Wiener diversity index (H') of 13 qualitative traits was 1.31, with coefficients of variation ranging from 25.01% to 45.07%. The average H' of six quantitative traits was 2.03, and the coefficients of variation ranged from 13.83% to 38.63%. Correlation analysis showed that 11 pairs of traits had extremely significant positive correlations, nine pairs had significant positive correlations, 10 pairs had extremely significant negative correlations, and 10 pairs had significant negative correlations. Principal component analysis extracted the first seven principal components with a cumulative contribution rate of 67.29%, and five superior germplasms with high comprehensive scores for leaves were screened according to principal component scores. Cluster analysis showed that the 120 germplasm resources were divided into seven groups at a Euclidean distance of 5.38: Group Ⅰ and Group Ⅱ had more germplasms, making up 75.83% of all materials; LZ099 and LZ110 in Group Ⅴ, along with LZ034 and LZ081 in Group Ⅲ, could serve as vital materials for tea breeding for their good characteristics such as big leaves and double buds.【Conclusion】Phenotypic traits of tea germplasm resources from Jiuwan Mountain, Guangxi show rich genetic diversity, with great development potential for breeding new distinctive tea varieties and innovative utilization of germplasm. Rare group conservation and exploration and utilization of core germplasms should be strengthened.

     

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