PNAS | June 20, 2006 | vol. 103 | no. 25 | 9578-9583

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. 

Tom Billings