The genetic diversity of wild populations of Rubia cordifolia L. in Shaanxi province based on SCoT analysis

Rubia cordifolia L. has been used as a traditional Chinese medicine for several centuries. In recent years, the resources of wild Rubia cordifolia have been declined sharply due to increased utilization and rising price. Therefore, it is of great urgency to evaluate and protect resources of wild plant of Rubia cordifolia. In our study, sixty-four individuals that represent eight wild populations of Rubia cordifolia L. were analyzed by Start Codon Targeted Polymorphism (SCoT) molecular markers. Genetic distance was calculated by POPGENE 3.2 software, cluster analysis was generated by NTSYS 2.10 software based on UPGMA method and Mantel Test was used to analysis the relationship between the genetic distances and geographical distance among the wild populations. The results showed a high genetic diversity of wild populations of Rubia cordifolia L. in Shaanxi province. A total of 182 bands were produced by 14 primers, among which 163 bands were polymorphic bands, and the percentage of polymorphic bands was 89.56%. The average value of Nei's genetic diversity index (H) was 0.293 6, Shannon's information index (I) was 0.444 6, genetic differentiation coefficient (Gst) was 0.555 3, and the gene flow (Nm) was 0.440 8, the wild populations were ranked by genetic diversity:AK > YL > SL > BJ > TC > YA > WN > XY. Mantel Test analysis demonstrated that the significant correlation was found between the genetic distances and geographical distances (r=0.776 4, P<0.05). There is a significant correlation between geographical and genetic distances. This study provides a theoretical basis for the protection and development of the resources of wild Rubia cordifolia L. germplasms.