Rice
Family Gramineae (or Poaceae)
Oryza sativa, rice (O. sativa 1), is the most important tropical cereal. It is an annual grass, 50-150 cm tall, with a more or less erect culm and a single leaf at each node. Leaf-blades narrow, up to 50 cm long, often with spiny hairs on the margin. The inflorescence is a terminal panicle, up to 40 cm long, usually with about 100 spikelets, open or compact, erect or drooping (O. sativa 2).
Distribution
Rice is the staple food of about half the human race, about 90% being cultivated and consumed in Asia (O. sativa 3). Although rice has been cultivated in China for more than 5000 years, the place of domestication is not known with certainty. Most likely this domestication took place in India or Southeast Asia. About 1500 BC it was taken to Indonesia and the Philippines. It was taken to Japan from China at about 100 BC, but it never spread into the Pacific. In ancient Egypt rice was unknown. The first report of it in Europe was after Alexander the Great’s conquest of India in 320 BC. After that the Moors took it to Spain and eventually it reached Italy in 1475. Finally, the Portuguese introduced it into Brazil and West Africa. It was taken to the US in 1865. In Australia commercial cultivation did not start until 1924.
As a result of the very long cultivation of rice, numerous varieties have developed. Well-known is their classification according to the conditions under which they are grown, e.g. upland rice or hill rice; and lowland rice or swamp rice. The former is grown as a rain-fed crop, the latter on irrigated or flooded land. Upland rice is much less important than lowland rice and provides less than 10% of the rice acreage in Asia. The biggest producer of highland rice is Brazil
In the cultivation of lowland rice the land is inundated (O. sativa 4), and the crop is grown in water until the approach of harvest. An ingenious system of small dikes (O. sativa 6) creates terraces (O. sativa 5) on sloping terrain in mountainous areas. This system of cultivation in many tropical countries is very expensive in labour, as planting (O. sativa 7), (O. sativa 8), harvesting (O. sativa 9), (O. sativa 10), (O. sativa 11), and threshing (O. sativa 12), (O. sativa 13), (O. sativa 14) is usually done by hand. Ploughing is usually done with oxen (O. sativa 15), (O. sativa 16), (O. sativa 17). In Asia seed is usually sawn in nurseries and later the seedlings are transplanted into fields with shallow water (O. sativa 18), (O. sativa 19). In many parts of the tropics two and sometimes three crops of rice can be grown each year.
Use
Rice is usually cooked by boiling or steaming and eaten with pulses, vegetables, fish or meat (O. sativa 20), (O. sativa 21), (O. sativa 22). Unhusked grain is known as paddy; husked rice is usually called brown rice because of the outer brownish layer that covers the seed; and milled rice is called white rice (O. sativa 23). European and American markets demand glossy and translucent grains. This is done by glazing white rice, but much of the proteins and vitamins are removed in doing so. Parched and puffed rice and rice flakes are also made from the grains. Ground rice, made from broken grains, and glutinous rice, which coagulates in cooking, are used for making sweetmeats. Rice powder provides a cosmetic in Asia, while rice starch, made from broken rice, is used in foods, cosmetics and textile manufacture. In the East rice is also used for the manufacture of beers, wines and spirits, e.g. sake in Japan. The husks are not only used as fuel for rice mills, but also for the manufacture of hardboard and as an abrasive. The rice bran contains oil, which can be used as cooking oil or for the manufacture of soap and industrial products. Rice straw is used for thatching and the manufacture of strawboard hats and mats. Rice paper is not made from rice, but from the pith of a tree.
The largest area of rice cultivation is in India. The biggest producers are China, India and Indonesia. Other important rice producing countries are Banagladesh, Thailand, Japan, Birma, Vietnam, Korea, the Philippines, Pakistan, Brazil, and the US. The largest exporters are Thailand and the US; the largest importers are Russia, Germany and the UK.