Genetic Diversity Of Oryza Rufipogon Griff. With SSR Markers In Hainan Province

The genetic diversity and structure of natural populations can determine the ability of a species to respond adaptively to future environmental changes. Investigating the patterns of genetic diversity of Oryza rufipogon Griff. in the field can reflect the causes of species extinction and help to lay a foundation of a scientific conservation strategy and germplasm management. Oryza rufipogon Griff. has been commonly known as the ancestor of cultivated rice and is the most important genetic resources in rice breeding. The Ex-situ and In-situ are two mainly conserved gene pools in wild rice studies. This study focuses the questions of sampling ways of ex-situ conservation and the place selection of in-situ. Meanwhile the study discussed the genetic diversity of Oryza rufipogon Griff. with SSR markers and also inquires the conservation strategies and methods for Oryza rufipogon Griff. in Hainan, China. The results indicated that:Sectionâ… is about the most sample quantities in ex-situ conservation of wild rice: If it is necessary to have the ratio of the sampling genetic diversity and the actually genetic diversity be more than 90% and 95%, the sampled numbers should be 25 or 30 individuals respectively.Sectionâ…¡: The tested populations of Oryza rufipogon Griff. in Hainan have abundant genetic diversity because 227 alleles were detected from 28 loci, with the average number of alleles per locus (A) of 8.1071, the effective number of alleles (Ae) of 4.419, the average expected heterozygosity (He) of 0.7475, the average observed heterozygosity (Ho) of 0.7062 and Shannon-weaver's information index (I) of 1.6048. The highest genetic diversity is Haikou(I=1.1319) and the lowest is Sanya(I=0.3826), the indices of the five populations was as following order: Haikou(HK)>Chengmai(CM)>Qionghai(QH) >Wenchang(WC)>Sanya(SY).Sentionâ…¢: The gene differentiation index (Fst) was 0.4649, meaning that the genetic variability among populations was high. The fixation indices within populations ( Fis) was -0.7069 and the estimate of out crossing rate (t) was 0.4570, it is suggested that this species is a typical plant with cross-pollinate system.Sentionâ…£: The genetic relationship among populations was studied by Nei genntic similar conefficient. The results showed that all of the populations were divided into 5 group when the conefficient is about 0.3, and all of the swatchs of each population were gathered and had no cross with other populations. So the individual differentiation among populations is very evidence. Falling the conefficient, population Sanya(SY) and Qionghai(QH) clustered together and population Wenchang(WC) and Chengmai(CM)...