Key message

The natural population in S. pohuashanensis had a high-level genetic diversity and higher level genetic differentiation.

Abstract

Sorbus pohuashanensis is an ornamental and economic tree species native to northern China. We investigated the genetic diversity and structure of natural populations of S. pohuashanensis to provide a scientific basis for the protection, development, and utilization of this tree species. We analyzed 544 samples from 18 natural populations of S. pohuashanensis collected from rural Chinese provinces using molecular marker technology. Genetic diversity was high at the species level: the mean number of alleles (N_a), the mean effective number of alleles (N_e), the mean expected heterozygosity (H_e), and the Shannon’s information index (I) per locus were 13.3750, 5.2550, 0.6965 and 1.6873, respectively. With the values of H_e and I (Shannon’s information index) of populations, the genetic diversity of the SXPQG population (H_e = 0.6215, I = 1.2360) was the highest, whereas that of HLJNEL population (H_e = 0.4273, I = 0.8055) was the lowest. Molecular variance analysis showed that intra-population variation (80%) was significantly higher than inter-population variation (20%), which was consistent with the genetic differentiation coefficient (F_st = 0.2120). According to UPGMA analysis, principal coordinate analysis, and population genetic structure analysis, the 18 populations were divided into 3 groups, and different degrees of infiltration were observed for each group. In addition, a significant genetic relationship was observed among populations and their geographical distance, and two populations (LNLTDZ and HBDHT) were recently affected by bottleneck effects. These results reveal novel insights concerning population genetics of S. pohuashanensis, and provide a basis for the conservation, development, and utilization of its genetic resources.