Rice
Oryza sativa
Amharic); Ruzii (Oromifa); Bariis (Somali); Vreejay, Oreeji, Wriji (Pashtu); Brenj,
Shali (Dari); Dhan chaval (Hindi)
Rice provided 700 calories/day/person or more for approximately 2.9 billion people
during the year 1997, according to FAO. Rice is the most important cereal in the
tropics, and in global terms the tonnage of rice grown is similar to that of maize and
wheat (FAO estimates for 2004 were 605, 721 and 627 million MT respectively).
Asian Rice; grown mainly in the flood plains of the Sahel, it has poor quality dark
coloured grains; it is used in some West African rituals. The two species were first
successfully crossed in 2002, with promising results for the hybrid.
One of the species, Oryza rufipogon and others, is Perennial Wild Rice
(Brownbeard Rice, with many synonyms), an aggressive and serious weed in rice
fields. Evidence suggests that O.sativa was originally derived from O.rufipogon; the
two species hybidise readily, producing a highly variable range of weedy perennial
wild rice types, including annual types, and much taxonomic confusion. The seed is
red-brown colour, 5–7 mm long. It propagates by seed (which shatters prematurely)
and by rhizomes.
The other Wild Rice, Zizania aquatica (family Poaceae), sometimes called
American Wild Rice, grows in eastern North America and was once an important
food of the Indians living in that area. It is now cultivated to produce a highly
valued, nutritious food, the “caviar” of cereals. It is a rich source of niacin and
riboflavin.
Improved varieties of rice have been developed so far mainly for irrigated and
favourable lowland areas, but in some countries their yield advantages are more than
offset by the higher prices of traditional rices such as the aromatic Basmati types.
Classification of Rice
The classification (taxonomy) of rice is not simple, and can be based on at least four
different characteristics:
- Upland (Hill or Dryland Paddy)—varieties which can be grown in regions with
adequate rainfall for 3-4 months. Cultivation methods are similar to other
cereals. - Paddy (Lowland or Swamp)—grown on artificially flooded fields. Some
varieties are adapted to grow under both paddy and upland conditions. - Floating—very rapid plant growth keeps up with the rising level of water, up to
5m deep.
glutenous. Most varieties are non-glutenous.
long grain; medium grain; short grain.
128 TONY WINCH
Riz (French); Reis (Germany); Arroz (Spanish & Portuguese); Ruz (Arabic and
There are more than 20 species of Oryza, but only O. sativa, Asian Rice, and
O. glaberrima, African Rice, are widely cultivated. African Rice is very similar to
- Cultivation Methods. On this basis there are three types:
- Grain Characteristics. On this basis there are two types, glutenous and non-
- Grain Shape and Size. On this basis there are four types: long, slender grain;