Objective The study was conducted to reveal the diversity of phenotypic traits of carambola leaves and explore the excellent germplasm resources so as to improve the protection and utilization of germplasm resources of Daguotianyangtao.

Method Taking the five species of carambola germplasm resources approved and named by the Crop Variety Approval Committee of Guangxi Zhuang Autonomous Region as research materials, six compound leaf traits, three terminal leaflet traits and three lateral leaflet traits were determined. The leaf phenotype and diversity characteristics were evaluated by variation analysis, correlation analysis, principal component analysis and cluster analysis.

Result The coefficient of variation of the 12 traits ranged from 9.97% to 28.94%, and the average coefficient of variation was 16.86%. The diversity was relatively rich. There were different degrees of correlation among the 12 phenotypic traits in the leaves of Daguotianyangtao, which could provide a certain theoretical basis for the improvement of leaf traits. Based on principal component analysis, 12 quantitative traits were divided into 4 principal components, and the cumulative variance contribution rate was 80.723%, which could be used as a comprehensive index for selection of leaf traits of Daguotianyangtao. Cluster analysis results showed that, when the square Euclidean distance was 5, all the materials were divided into 3 groups, and the second group was the best in 9 phenotypic traits such as compound leaf length, compound leaf width and compound leaf principal axis length, which could be selected as the prioritized germplasm resources for leaf trait breeding.

Conclusion Based on the results of variation analysis, correlation analysis and principal component analysis of the phenotypic characteristics of the tested Carambola varieties, Daguotianyangtao 2 showed the optimal performance in compound leaf length, compound leaf width, compound leaf principal axis length, compound leaf fresh weight, and leaflet number, terminal leaflet length, lateral leaflet length, lateral leaflet width, and lateral leaflet fresh quality among the 9 phenotypic traits, and could be used as a prioritized variety for leaf trait breeding.