Phenotypic diversity analysis of Polygala tenuifolia Willd germplasm resources in China

Polygala tenuifolia Willd is a perennial herb in the family Polygalaceae and is used as an expectorant and stimulant in traditional Chinese medicine. There is a large demand for P. tenuifolia, while the good cultivars of P. tenuifolia are not enough. In this study, we collected 157 germplasm resources of P. tenuifolia from different regions in China, and 12 phenotypic traits of these samples were analyzed using correlation analysis, principal component analysis (PCA), and cluster analysis methods. The correlation analysis showed the associations between different traits, and the first four principal components contributed 62.63% of the total variation. They contained most of the information of five above-ground traits and eight root traits. Phylogenetic clustering divided materials divided into four taxa, with characteristics of high-yielding specific material, long-rooted specific material, multi-branching specific material, and high plant height specific material, respectively. Our study provides the material and theoretical basis for the utilization of germplasm resources, parental selection, and varietal improvement of P. tenuifolia.