Rice: Origins and Development

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Basic Species Information

The genus Oryza consists of 24 species, among which two domesticated species are recognized. On the one hand, there is Asian rice, Oryza sativa; today one of the most widely grown and productive of world crops, which had its origins in southern and eastern Asia. On the other hand, there is African rice, Oryza glaberrima, which is native to and mostly restricted to western Africa (see Fig. 1). Asian rice is conventionally divided into two subspecies, subsp. japonica and subsp. indica, although more recent genetics suggests that five distinct groups should be recognized within O. sativa (Garris et al. 2005): indica, aus, tropical japonica, temperate japonica, and aromatic. Rice is closely related to bamboos but distantly related to the major cereals maize, wheat, and sorghum (Vaughan 1994). Oryza sativa and O. glaberrima and their wild progenitors are diploids (2n = 24) with AA genomes. Asian rice is closely related to a wild complex of a ...