Genetic variation in Rhodomyrtus tomentosa (Kemunting) populations from Malaysia as revealed by inter-simple sequence repeat markers

Kemunting (Rhodomyrtus tomentosa) from the Myrtaceae family, is native to Malaysia. It is widely used in traditional medicine to treat various illnesses and possesses significant antibacterial properties. In addition, it has great potential as ornamental in landscape design. Genetic variability studies are important for the rational management and conservation of genetic material. In the present study, inter-simple sequence repeat markers were used to assess the genetic diversity of 18 R. tomentosa populations collected from ten states of Peninsular Malaysia. The 11 primers selected generated 173 bands that ranged in size from 1.6 kb to 130 bp, which corresponded to an average of 15.73 bands per primer. Of these bands, 97.69% (169 in total) were polymorphic. High genetic diversity was documented at the species level (H(T) = 0.2705; I = 0.3973; PPB = 97.69%) but there was a low diversity at population level (H(S) = 0.0073; I = 0 .1085; PPB = 20.14%). The high level of genetic differentiation revealed by G(ST) (73%) and analysis of molecular variance (63%), together with the limited gene flow among population (N(m) = 0.1851), suggests that the populations examined are isolated. Results from an unweighted pair group method with arithmetic mean dendrogram and principal coordinate analysis clearly grouped the populations into two geographic groups. This clear grouping can also be demonstrated by the significant Mantel test (r = 0.581, P = 0.001). We recommend that all the R. tomentosa populations be preserved in conservation program.