This article is about the food grain; see also rice (disambiguation).Rice (Oryza sativa) is a plant of the grass family, which feeds more than half of the world's human population. Rice cultivation is well suited to poor countries as it is very labor-intensive, but with plenty of water for irrigation, can be grown practically anywhere, even on steephillsidessides.
Rice is the world's third largest crop, behind maize and wheat — both of which have significant uses outside of human nutrition.
In some instances, a deepwater strain of rice, often called floating rice is grown. This can develop elongated stems capable of coping with water depths exceeding 2 meters (6 feet).
Rice paddies are an important habitat for birds such as herons and warblers, and a wide range of amphibians and snakes. They perform a useful function in controlling insect pests.
Whether it is grown in paddies or on dry land, rice requires a great amount of water compared to other food crops, making rice growing a controversial practice in some areas, particularly in the United States and Australia, where rice farmers use 7% of the nation's water to generate just 0.02% of GDP. However, in nations that have the periodical rain season and typhoons, rice paddies serve to keep the water supply steady and prevent flood from reaching a dangerous level.
Colonial South Carolina and Georgia grew and amassed great wealth from the slave labor obtained from the Senegambia area of West Africa. At the Port of Charleston, through which 40% of all American slave imports passed, slaves from this region of Africa brought the highest prices, in recognition of their prior knowledge of rice culture, which was put to use on the many rice plantations around Georgetown, Charleston, and Savannah. From the slaves, plantation owners learned how to dike the marshes and periodically flood the fields. At first the rice was milled by hand with wooden paddles, then winnowed in sweetgrass baskets (the making of which was another skill brought by the slaves). The invention of the rice mill increased profitability of the crop, and the addition of water power for the mills in 1787 by millwright Jonathan Lucas was another step forward. Rice culture in southeastern USA became less profitable with the loss of slave labor after the American Civil War, and it finally died out just after the turn of the 20th century.
Indian rice varieties include long-grained Basmati (grown in the North), medium-grained Patna and short-grained Masoori. One variety, available in the South Indian state of Kerala, is usually referred to in English as boiled rice. This is prepared by boiling it just after harvesting, in huge pans, often over coconut-shell fires, to kill any fungi or other contaminants. It is then dried, and the husk removed later. It often displays small red speckles, and has a smoky flavour from the fires.
Scientists are working on so-called golden rice which is genetically modified to produce beta carotene, the precursor to vitamin A. This has generated a great deal of controversy over whether the amount of beta carotene would be significant and whether genetically modified foods are desirable.
Draft genomes for the two commonest rice cultivars, indica and japonica, were published in April 2002.