Low levels of genetic diversity within populations and high differentiation among populations of a wild rice, Oryza granulata Nees et Arn. ex Watt., from China

To characterize genetic diversity within and among populations of Oryza granulata Nees et Am. ex Watt., allozyme variation was assayed for 17 loci in 15 natural populations from Hainan and Yunnan provinces, China, using starch gel electrophoresis. A low level of genetic variability within populations (the mean A 1.09, p = 6.33%, H-e = 0.016, and H-o = 0.009), but high genetic differentiation (F-ST) among populations was observed. The low amount of genetic variability of the species may be strongly affected by founder effect because of the marginal nature of the populations in China. The results also indicate that the restricted gene flow occuring between the two regions as well as the characteristics of O. granulata as a colonizing plant species are probably of significance in shaping the observed population genetic structure. Finally, an appropriate strategy for sampling more populations, but fewer individuals within populations, was proposed for the conservation of O. granulata in China.