Genetic diversity in wild relatives of rice and domestication events

Abstract

Two cultivated rice species, Oryza saliva and O. glaberrima, are classified as the O. saliva complex, together with five related wild species. These wild taxa are O. rufipogon (Asia and Oceania), O. barthii (Africa), O. longistaminata (Africa), O. glumaepatula (Latin America) and O. meridionalis (Oceania). They are diploid and share the AA genome in common. According to the gene pool concept (Harlan 1975), O. saliva of Asiatic origin forms a primary gene pool with its wild progenitor O. rufipogon, and O. glaberrima of African origin forms a second primary gene pool with its wild progenitor O. barthii. During the past decade, a wealth of data, obtained by molecular tools, on AA-genome Oryza species have significantly increased our knowledge of genetic diversity among and within species of this taxonomic group. However, speciation mechanisms are still not fully elucidated. In this chapter, we intend to draw an evolutionary perspective of the O. saliva complex from the viewpoints of genetics and ecology, with special emphasis on the evolutionary dynamics of O. rufipogon and domestication that occurred within the species.