Genetic differentiation in Thai populations of the rare species Afgekia sericea Craib (Leguminosae) revealed by RAPD-PCR assays

Abstract

Genetic diversity within and among populations was investigated using RAPD-PCR assays in a rare species, Afgekia sericea Craib. Two hundred and sixty-nine individuals were sampled from nine geographically isolated populations from northeastern Thailand. This study includes 73 RAPD markers. Within population polymorphism as measured by percentage of polymorphic RAPDs, varied between 38.4% and 60.3%. Genetic variability was measured using Shannon's information index and partitioned into between- and within-population components. Overall, genetic variation among A. sericea populations was high (H(sp)-H(pop))/H(sp) = 48.2%. The genetic diversity for the species (H(sp)) was 43.2%. Mean of within-population values (H(pop)) for all populations was 0.224. The total genetic diversity was explained by high variation among populations (mean G(st) = 0.426), which is consistent with low gene flow among populations (N(m) = 0.35). High between-population genetic variation observed in this study could be explained by limited migration through seed and/or pollen dispersal among populations. Conservation strategies of A. sericea are discussed in the context of these results.