Allozyme variation and conservation genetics of common wild rice (Oryza rufipogon Griff.) in Yunnan, China

In order to reveal levels and distribution of genetic variation within Oryza rufipogon Griff. of Yunnan, China, where one of the centers of genetic diversity for Asian cultivated rice O. sativa L. is located, allozyme variation encoded by 22 loci was electrophoretically analyzed in 149 individuals of all three existing populations as well as five from other regions (Guangxi, Hainan and Jiangxi provinces) of China. As compared to the level of genetic diversity (the mean A = 1.2, P = 24.1%, Ho = 0.045 and He = 0.079) for the populations from other regions, a rather low genetic diversity (the mean A = 1.1, P = 7.6%, Ho = 0.007 and He = 0.011) was found in Yunnan, which may originate from marginal nature of these populations, recent reduction of populations and consequent drift. The result suggests that the current center of genetic diversity for O. rufipogon fail to agree with that for cultivated rice in China. The genetic differentiation for all the eight populations (F-ST = 0.254) was slightly lower than that for three populations from Yunnan (F-ST = 0.302), indicating a fairly high genetic differentiation in the region. Finally, a conservation plan for sampling/preserving fewer populations but more individuals from each population for the species was given, and an appropriate strategy for conserving the three surviving populations from Yunnan was proposed.