Objective Rosa persica, the only single-leaf species of Rosa, is an important material for rose breeding. It is mainly distributed in northern Xinjiang of northwestern China, but it is at risk of extinction due to human damage and environmental changes. This study analyzed the phenotypic diversity of Rosa persica and explored the rule of its phenotypic variation, aiming to provide theoretical guidance for better protection and utilization of Rosa persica germplasm resources.

Method In this study, 270 individual plants from 9 natural populations of Rosa persica were used as research materials, and the data of 19 phenotypic traits were collected. Nested analysis of variance, Pearson correlation analysis, principal component analysis and cluster analysis were used to explore the phenotypic variation and diversity level of the plants.

Result (1) The phenotypic diversity of 9 natural populations was higher, and the mean coefficient of variation and Shannon diversity index of 19 phenotypic traits was 15.90% and 2.031, respectively. The phenotypic coefficient of variation of 9 populations ranged from 10.32% (P4) to 13.19% (P8), showing moderate variation. The Shannon diversity index ranged from 1.274 (P5) to 1.825 (P8), and the P8 population showed a high diversity level. (2) The 19 phenotypic traits had significant differences between populations and within populations (P < 0.01). The average phenotypic differentiation coefficient between populations was 41.23%, and the phenotypic variation was mainly from within populations. (3) Pearson correlation analysis showed that there were significant correlations between flower diameter and leaf area, petal area and flower spot percentage. (4) A total of 5 principal components were extracted from the principal component analysis, with a cumulative contribution rate of 80.463%, and the two principal components with the largest contribution rate mainly explained the characteristics of flowers and leaves. (5) The 9 populations of Rosa persica could be divided into 2 groups by cluster analysis. The first group was large flower group, including P6, P7 and P8, and the second group was small flower group, including P1, P2, P3, P4, P5 and P9.

Conclusion The phenotypic diversity and variation level of Rosa persica in Xinjiang are high, and the sources of variation are mainly concentrated in the population.