| Conservation biology is a scientific subject which studies on the basic backgrounds related to biological diversity conservation. Its key yield is about the conservation of genetic diversity referring the total genetic variation in different populations or different individuals within the same population. The genetic variations may include a large mount of superior genes and determine the potentiality of species evolution. This study focuses the genetic diversity of Oryza rufipogon both in-situ and ex-situ conserved populations based on the SSR molecular markers and also inquires the conservation strategies and methods for O. rufipogon in China. The text of this thesis is divided into following 4 sections.Section I is about the comparative study of the genetic diversities from both in-situ and ex-situ conserved gene pools. Two populations named Anjiashan and Shuitaoshu populations in Dongxiang County were used for this purpose. The results indicated that the indices of gene diversity (He) of in-situ and ex-situ gene pools are 0.5000 and 0.3555 respectively. The dendrogram of the total samples showed that the cluster of ex-situ samples was only one of the branches while in-situ samples clustered in wide ranges. The indices of both in-situ and ex-situ samples of Shuitaoshu population were similar and the samples clustered tangly in the dendrogram which seemed that the two gene pools were similar. However, about 40% of the successive numbers from ex-situ samples were clustered together meaning that the successive number samples might be from the same clone. Therefore, the ex-situ samples could not be representative for the genetic diversity of the original populations. The suggestion is that it is necessary to have another collection of genetic resources of O. rufipogon for ex-situ conservation.Section II: The genomic DNA samples of 5 populations were amplified with 30 pairs of SSRprimers. The numbers of 5, 10, 15.....etc. of the total materials were sampled randomly each timeand repeated 10 times, then the average number of alleles and the ratio to the total number of alleles were calculated. Using the sampled numbers and the ratios of total number of alleles as axes to make the diagram. The results indicated that if we sample the number based on turning points of the diagram, 10-30 individuals could be representative for the genetic diversity of the total population. If it is necessary to have the ratio of total alleles be more than 90% and 95%, the sampled numbers should be 15-25 or 30-40 individuals respectively. This study also indicated that the distance between two samples should be more than 12 m for large populations and 5-8 m for smaller populations.Section III: Seven populations of O. rufipogon in-situ conservation sites were selected to study the genetic diversity and the conservation strategies. Total 150 alleles were detected with 30 SSR primers. The average number of alleles of each locus was 5.4 and the average gene diversity (Hs) was 0.77. The indices of the seven populations was as following order: Guangdong (0.5130)>Hainan (0.4692)>Guangxi (0.3860)>Hunan (0.3520) >Jiangxi (0.3485) >Fujian (0.3154) > Yunnan (0.1444). Among the populations of Guangdong, Guangxi, Hunan and Jiangxi, the order was from south to north, which meant that the lower the latitude, the high the genetic diversity, confirming that South China is the genetic diversity center of O. rufipogon. Moreover, the samples from the seven populations were clustered separately in the dendrogram and Hunan population was closer to Yunnan population while Jiangxi population was closer to Hainan population. It could be inferred that the seven populations were different from each other and all of them should be conserved, and the Northern Marginal Populations were isolated populations because of the fragmented environments and ecosystems. The fact that the low genetic diversity of Yunnan population inferred that cultivated rice is important for enriching the genetic diversity of wild rice.Section IV: Based on the SSR dat...
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