中国普通野生稻(Oryza rufipogon Griff.)原生境保护与未保护居群的遗传多样性比较

Comparison of Genetic Diversity between in-situ Conserved and Non-conserved Oryza rufipogon Populations in China

为了明确我国已建立的普通野生稻原生境保护居群的遗传多样性状况及其代表性,利用24对SSR引物对15个原生境保护居群的427份普通野生稻材料和在我国野生稻分布区内按照纬度划分后随机挑选的15个未保护居群的357份普通野生稻材料进行遗传多样性分析。结果表明,保护居群24个位点的平均有效等位基因数(Ae)为5.98,平均香农指数(I)为1.90,均大于未保护居群在24个位点的平均Ae(5.85)和I(1.86)值,但保护居群在24个位点的平均预期杂合度(He)为0.79,略小于未保护居群He值(0.80)。显著性检验结果显示,保护居群和随机挑选的未保护居群在24个位点上及居群水平上的Ae、I和He值差异不显著,表明保护居群可以代表我国普通野生稻的遗传多样性状况。保护居群的特有等位变异数(Sa)为40,远大于未保护居群的20,说明保护居群保护了更多的特殊基因,具有较高的保护价值。根据前人的研究结果,对应普通野生稻保护居群的地理信息,发现15个保护居群涵盖了我国普通野生稻分布区内所有已知的典型地理类型,表明我国普通野生稻原生境保护居群具有典型性。由此可以看出,我国已建立的15个普通野生稻原生境保护点的选择是科学合理的。根据对我国普通野生稻遗传结构的分析,建议下一步开展的普通野生稻原生境保护点建设应以广西南部及广东为主。

By the end of 2007, altogether 15 Oryza rufipogon in-situ conservation sites had been established in different parts of China. However, these sites were selected only on the basis of the scientists’ experience and the materials submitted by different provinces. Thus, the validity of the selected populations still needs to be verified. By virtue of 24 pairs of SSR markers, the research was conducted on genetic diversity for 427 accessions of Oryza rufipogon from the 15 in-situ conserved populations and 357 accessions from 15 non-conserved populations which were randomly selected according to their latitude, so as to clarify the genetic diversity and representativeness of the existing Oryza rufipogon in situ conserved populations in China. The results indicated that the average Ae and I of the 24 lociof the conserved populations were 5.98 and 1.90 respectively, which were both higher than those of non-conserved populations （5.85 and 1.86 respectively）. However, the average He of the 24 loci of the conserved populations was 0.79, which was lower than that of the non-conserved populations （0.80）. Besides, test of significance on the Ae, I, and He of the SSRloci showed that there was no significant difference between the two populations, demonstrating that the genetic diversity of the conserved populations could be representative of the Oryza rufipogon populations in China. Moreover, the number of specificalleles of the conserved populations was 40, which far exceeded that of the non-conserved populations（20）, showing that the conserved populations possessed more unique genes which are worth conserved. In addition, based on previous research findings and in accordance with the geographic information of the conserved populations, we found that the 15 conservation sites covered all the typical geographic types in the Oryza rufipogon distribution areas in China. Thus, we may conclude that the 15 in-situ conservation sites were scientifically and rationally selected. On the basis of the analysis of the genetic structure of the Oryza rufipogon populations in China, it was recommended that future in-situ conservation sites should be established mainly in the southern part of Guangxi and in Guangdong.