AFLP analysis of genetic variation in wild populations of five Rhododendron species in Qinling Mountain in China

Abstract

The genetic diversity in 22 populations of 5 wild Rhododendron species in Qinling Mountain in China was evaluated using amplified fragment length polymorphism (AFLP). Four AFLP selective primer combinations generated a total of 135 bands with their sizes ranging from 67 kb to 501 kb, among which 123 bands were found to be polymorphic, accounting for 92.04% variations. POPGENE analysis indicated that all the five species had high levels of genetic diversity, with percentage of polymorphic loci (PPL) ranging from 87.2 to 99.8% and effective number of alleles (ne) varying from 1.4205 to 1.9957. Shannon’s Information Index (I) differed from 0.4286 to 0.6921, while Nei’s gene diversity (H) varied from 0.2711 to 0.4989. The 5 species showed similar levels of genetic variations, with Hs and Ht ranging from 0.2253 to 0.4041 and from 0.2400 to 0.4994, respectively. The coefficient of gene differentiation among 22 populations (Gst) was 0.0923, accounting for 90.8% genetic diversity and only 9.2% genetic variations among the populations tested. The differences among populations were low in comparison with the previous studies on other species using the same technique. Low level of the genetic differences among Rhododendron populations investigated in the present study might be due to their outcrossing reproductive system. The analysis of molecular variance (AMOVA) also showed that variations among the species and populations were low, mainly due to a high variation within the populations. Based on unbiased genetic distances determined by an unweighted pair group method using arithmetic mean (UPGMA) phenogram, all populations could be grouped into Rhododendron species.