Rice

Origin

Rice belongs to the Poaceae or Gramineae family and genus Oryza. The genus Oryza includes 20 wild species and two cultivated species. The wild species are generally found in humid tropics and subtropics. Of the two cultivated species, African rice (Oryza glaberrima) is native and confined to west Africa, whereas Asian rice (Oryza sativa) is commercially grown in all continents. The reason for the parallel evolution of the above two cultigens in Africa and Asia is the origin of genus Oryza in Gondwanaland in the supercontinent Pangaea before it fractured and drifted apart. Oryza‘s origin in Gondwanaland is also confirmed by the presence of closely related wild species of rice in Australia, Central America, and South America. The wild rice species of North America is Zizania palustris. Traditionally, this species was self-propagated and harvested only by [Page 374]Native Americans in the Great Lakes area. Today, it is grown in Minnesota and northern California.

There are two major subspecies in Oryza sativa: the sticky, short-grained japonica (or sinica) variety, and the nonsticky, long-grained indica variety. Japonica is generally cultivated in dry fields in east Asia, whereas indica is mostly cultivated submerged under water in tropical Asia. Although the origin of domestication of Asian rice is still controversial, the scientific consensus concludes that Oryza sativa indica was domesticated in eastern India and japonica in southern China. A recent archaeological study suggests a single domestication of rice in the lowlands of China. The Yangtze was probably the site of the earliest rice cultivation.

China introduced japonica rice to Korea before 1030 B.C.E. Rice cultivation in Japan began in the late Jomon period in about 1000 B.C.E. From the Indian subcontinent and mainland southeast Asia, the indica rice spread to Sri Lanka before 543 B.C.E., to the Malay Archipelago, to the Indonesian islands between 2000 and 1400 B.C.E., and to central and coastal China.

...