Genetic Diversity And Relationships Between Common Wild Rice (from South Asia, Southeast Asia) And Asia Cultivated Rice

It is known that common wild rice is the ancestor of cultivated rice. The cultivated rice further differentiated into Oryza sativa japonica and Oryza sativa indica. However, the genetic structure and the relationships among Oryza sativa indica, Oryza sativa japonica and Oryza rufipogon have still not been clarified well till now.In this study, 15 Oryza sativa indica, 23 Oryza sativa japonica and 37 Oryza rufipogon, being collected from 13 different countries, were used to analyze the genetic diversity of rice based on SSR markers. 35 pairs of SSR primers were selected which random distribute in 12 chromosomes of rice. The main results were as follows:1. Genetic diversity among Rufipogon, japonica and indicaIn the groups of Oryza Rufipogon, Oryza sativa japonica and Oryza sativa indica, 249, 137 and 111 allels were found. The average gene numbers was 7.11, 3.91, 3.17, and the average gene diversity was 0.5823, 0.3728, 0.3234, and the polymorphism inofmration content (PIC) was 0.6161,0.4001 and 0.3509, respectively.It is concluded that the genetic diversity level of Oryza Rufipogon was higher than cultivated rice, and Oryza sativa japonica was higher than Oryza sativa indica in cultivated rice.2. Relationships among Rufipogon, japonica and indicaFrom the genetic distance aspect, the genetic distance between rufipogon-japonica was 0.6712, rufipogon-indica was 0.3987 and japonica-indica was 0.5721. From the Genetic differentiation aspect, the Genetic differentiation between rufipogon -japonica was 0.3222, rufipogon-indica was 0.2423 and japonica-indica was 0.4091. From the gene flow aspect, the gene flow between rufipogon-japonica was 0.5259 rufipogon-indica was 0.7818, japonica-indica was0.3611.We can draw the conclusion that, in south Asian and south-east Asian, the relationships between rufipogon rice and indica rice was closer than rufipogon rice and japonica rice. The japonica rice and indica rice had the most differentiation in genetic differentiation. Associated with some other results done by our lab, we have further guessed that the evolution of japonica and indica consisted with the theory of "two-origin".