High levels of genetic differentiation of Oryza officinalis Wall. ex Watt. from China

In order to determine the population genetic structure of wild rice (Oryza officinalis Wall. ex Watt.), an endangered tropical and subtropical species, allozyme diversity encoded by 24 loci was analyzed electrophoretically in 145 individuals of eight natural populations from Hainan, Guangxi, and Yunnan provinces, China. A fairly high genetic differentiation (F(ST) = 0.882 and mean I = 0.786) was found among the studied populations. Our results suggest that restricted gene flow may play a significant role in shaping such a population genetic structure. In addition, high genetic differentiation among populations within a geographically limited region may stem from a reduced population size and consequent genetic drift.