Genetic diversity in coastal and inland desert populations of Peganum harmala L. (Peganaceae)

This study compared the genetic diversity within and among six naturally growing coastal and inland populations of Peganum harmala by using random amplified polymorphic DNA (RAPD) technique. Seven primers generated a total of 63 RAPD bands (loci) of which 60 (95.24%) were polymorphic across all individuals. The genetic diversity of P. harmala at the population level and species level were percentage polymorphic loci (PPL) = 42.59%, Nei’s gene diversity (h) = 0.1892, Shannon information index (I) = 0.2711 and PPL = 95.24%, h = 0.3116, I = 0.4723, respectively. The value of differentiation (the coefficient for gene divergence, Gst = 0.3925) and analysis of molecular variance (AMOVA) indicated that there was a relatively high genetic differentiation within populations, and about one-six of the genetic variations occurred among populations. Analysis of fixation indices (FST) = 0.15500, p < 0.00196 showed low degree of differentiation among populations. The genetic variation in the coastal populations was higher than the variation in the inland populations. The present study suggests that the gene drift may play an important role in the differentiation of P. harmala populations. The in situ conservation of the species should focus on establishing more sites to protect the natural populations and their habitats, while the ex situ conservation needs to focus on enhancing the exchange of seeds and seedlings among populations to facilitate gene flow, exchange and recombination.