9 June 2006 (Proceedings of the National Academy of Sciences of the United States of America) – A study tracing the origins of Asian wild rice and rice cultivation has determined that rice was likely to be domesticated in East India-Myanmar-Thailand (Orzya sativa indica) and Southeren China (Orzya sativa japonica). Abstract is cited here, full text requires subscription.
Phylogeography of Asian wild rice, Oryza rufipogon, reveals multiple independent domestications of cultivated rice, Oryza sativa
Jason P. Londo, Yu-Chung Chiang, Kuo-Hsiang Hung, Tzen-Yuh Chiang, and Barbara A. Schaal
Cultivated rice, Oryza sativa L., represents the world’s most important staple food crop, feeding more than half of the human population. Despite this essential role in world agriculture, the history of cultivated rice’s domestication from its wild ancestor, Oryza rufipogon, remains unclear. In this study, DNA sequence variation in three gene regions is examined in a phylogeographic approach to investigate the domestication of cultivated rice. Results indicate that India and Indochina may represent the ancestral center of diversity for O. rufipogon. Additionally, the data suggest that cultivated rice was domesticated at least twice from different O. rufipogon populations and that the products of these two independent domestication events are the two major rice varieties, Oryza sativa indica and Oryza sativa japonica. Based on this geographical analysis, O. sativa indica was domesticated within a region south of the Himalaya mountain range, likely eastern India, Myanmar, and Thailand, whereas O. sativa japonica was domesticated from wild rice in southern China.