Abstract:

The aim of this study is to reveal the genetic diversity of different populations of Crataegus songorica and to provide a scientific basis for its protection and sustainable utilization. The experimental materials included 92 samples, which were selected from Daxigou, Huocheng County in Xinjiang and analyzed by combining the analysis of phenotypic trait variation and the SSR marker. Results showed that there was considerable genetic variation in the phenotypic traits of different C. songorica populations, as the variation coefficient varied from 2.96% to 71.32%, and the phenotypic variation was mainly caused by the variation within population, as the mean phenotypic differentiation coefficient was 13.90% among populations and 86.10% within population. A total of 739 loci were detected from five populations by 43 SSR primers, and the polymorphism loci ratio was 90.53% at the species level. Nei’s diversity index, Shannon’s diversity index (I), the gene diversity within population (H_s), the total population genetic diversity (H_t), genetic differentiation coefficient and gene flow were 0.2377, 0.3712, 0.1635, 0.2023, 0.1916 and 2.1116, respectively. Comprehensive analysis suggested that the total genetic diversity of C. songorica was higher in Daxigou, and the genetic differentiation among populations was smaller. The results of UPGMA clustering showed that five populations formed two sub-types, and the differences in different habitats were the main causes of the discrepancy among populations. We conclude that the genetic diversity of C. songorica of different populations was high both at phenotypic and molecular levels in Daxigou, and there was a visible genetic differentiation within population, moreover differentiation trends had regional characteristics. Therefore, in situ conservation is supposed to be an effective method to protect C. songorica.

Key words: Crataegus songorica, SSR, phenotypic traits, genetic diversity