Abstract:
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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.