AppearanceA grass which can grow to over 1 m tall, or to 5 m long in deep water.
The stem is upright and composed of a series of joint-like nodes, with a leaf growing from each node.
The seeds (or grain) grow on branch-like spikes which arch over. The grain is the most economically important part of the rice plant, and its endosperm is the final product consumed.
NamingRice has been cultivated since ancient times and 'Oryza' is a classical Latin word for rice. 'Sativa' means 'cultivated'.
Common name(s): rice, paddy rice, chowdhury rice (English); dhanya, vrihi, nivara, syali (Sanskrit); dhan, chaval (Hindu); chal (Bengal); dangar, choka (Gujarat); nellu, arisi (Tamil).
Oryza sativa contains two major subspecies: the sticky, short grained japonica or sinica variety, and the nonsticky, long-grained indica variety. Japonica varieties are usually cultivated in dry fields, in temperate East Asia, upland areas of Southeast Asia and high elevations in South Asia, while indica varieties are mainly lowland rices, grown mostly submerged, throughout tropical Asia. Rice is known to come in a variety of colors, including: white rice, brown rice, black rice, purple rice, and red rice. Black rice (also known as purple rice or forbidden rice) is a range of rice types, some of which are glutinous rice. Varieties include but are not limited to Indonesian black rice and Thai jasmine black rice.
A third subspecies, which is broad-grained and thrives under tropical conditions, was identified based on morphology and initially called javanica, but is now known as tropical japonica. Examples of this variety include the medium grain 'Tinawon' and 'Unoy' cultivars, which are grown in the high-elevation rice terraces of the Cordillera Mountains of northern Luzon, Philippines.
Glaszmann (1987) used isozymes to sort Oryza sativa into six groups: japonica, aromatic, indica, aus, rayada, and ashina.
Garris et al. (2004) used SSRs to sort Oryza sativa into five groups; temperate japonica, tropical japonica and aromatic comprise the japonica varieties, while indica and aus comprise the indica varieties.
DistributionOryza sativa is cultivated in Europe, Africa, tropical and temperate Asia, Australia, and North and South America.
There have been plenty of debates on the origins of the domesticated rice. In 2011, genetic evidence published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) shows that all forms of Asian rice, both indica and japonica, spring from a single domestication that occurred 8,200–13,500 years ago in China of the wild rice Oryza rufipogon. A 2012 study published in Nature, through a map of rice genome variation, indicated that the domestication of rice occurred in the Pearl River valley region of China. From East Asia, rice was spread to South and Southeast Asia. Before this research, the commonly accepted view, based on archaeological evidence, is that rice was first domesticated in the region of the Yangtze River valley in China.
The precise date of the first domestication is unknown, but depending on the molecular clock estimate used by the scientists, the date is estimated to be 8,200 to 13,500 years ago. This is consistent with known archaeological data on the subject.
HabitatCommonly in river valleys and other areas where water is abundant, but also cultivated in some dryland areas.
UsesRice is the most widely grown tropical cereal, and over 400 million tonnes of milled rice is produced each year. The importance of rice has been recognised for many centuries - in India it was once known as 'dhanya' meaning 'the sustainer of the human race'. Rice is a staple food of South Asia and a vast number of people are employed in its cultivation.
Not only is rice used in a variety of ways as a foodstuff, but it is also an ingredient in medicines and cosmetics, and has a role in crafts and religious ceremonies.
Some text fragments are auto parsed from Wikipedia.http://www.kew.org/plants-fungi/Oryza-sativa.htm