Domestication and geographic origin of Oryza sativa in China: insights from multilocus analysis of nucleotide variation of O. sativa and O. rufipogon.

Previous studies have indicated that China is one of the domestication centres of Asian cultivated rice (Oryza sativa), and common wild rice (O. rufipogon) is the progenitor of O. sativa. However, the number of domestication times and the geographic origin of Asian cultivated rice in China are still under debate. In this study, 100 accessions of Asian cultivated rice and 111 accessions of common wild rice in China were selected to examine the relationship between O. sativa and O. rufipogon and thereby infer the domestication and evolution of O. sativa in China through sequence analyses of six gene regions, trnC-ycf6 in chloroplast genomes, cox3 in mitochondrial genomes and ITS, Ehd1, Waxy, Hd1 in nuclear genomes. The results indicated that the two subspecies of O. sativa (indica and japonica) were domesticated independently from different populations of O. rufipogon with gene flow occurring later from japonica to indica; Southern China was the genetic diversity centre of O. rufipogon, and the Pearl River basin near the Tropic of Cancer was the domestication centre of O. sativa in China.