Rice

History

Early Spread of Rice

• From an early beginning somewhere in the Asian arc, the process of diffusion has carried Rice in all directions until today it is cultivated on every continent save Antarctica.
• In this early hearth area, rice was grown in forest clearings under a system of shifting cultivation. The crop was grown by direct seeding and without standing water.
• Rice was grown on "farms" under conditions only slightly different from those to which wild rice was subject. A similar but independent pattern of the incorporation of wild rice into an agricultural system may well have taken place in one or more locations in Africa at approximately the same time.
• It was in China that the processes of puddling soil and transplanting seedlings were likely refined. Both operations became integral parts of rice farming and remain very widely practiced to this day.
• Transplanting, like puddling, provides the farmer with the ability to better accommodate the rice crop to a finite water supply by shortening the field duration (since seedlings are grown separately, and at a higher density) and adjusting the planting calendar.
• With the development of puddling and transplanting, rice became truly domesticated. In China, the history of rice valleys and low-lying areas is longer than its history as a dry land crop.
• In South-East Asia, by contrast, rice was originally produced under dry land conditions in the uplands, and only recently did it come to occupy the vast river deltas.
• Migrant peoples from South China or perhaps Northern Vietnam carried the traditions of wetland rice cultivation to the Philippines during the second millennium B.C. and deutero-Malays carried the practice to Indonesia about 1500 B.C. from China or Korea, the crop was introduced to Japan no later than 100 B.C.
• Movement to Western Indian and to Sri Lanka was also accomplished very early. The crop may well have been introduced to Greece and neighboring areas of the Mediterranean by the returning members of Alexander the Great’s expedition to India ca. 344-324 B.C.
• From Greece and Sicily, rice spread gradually throughout the Southern portions of Europe and to a few locations in North Africa.
• Interestingly enough, medical geographers in the 16th Century played an important role in limiting the adoption of rice as a major crop in the Mediterranean area.
• During the 16th and early 17th Centuries, malaria was a major disease in Southern Europe, and it was believed to be spread by the bad air (hence the origin of the name) of swampy areas.
• Major drainage projects were undertaken in Southern Italy, and wet land rice cultivation was discouraged in some regions.
• In fact, it was actually forbidden on the outskirts of a number of large towns. Such measures were a significant barrier to the diffusion of rice in Europe.
• Carbondioxide has long been the prime suspect for the green house effect and warming up of early, but it is not known that, methane traps 20 times more energy.
• It is agreed that methane concentrations are increasing at the rate of approximately 1% a year.
• A major methane source, perhaps even the largest of all, is flooded rice land. Not only do methane-producing bacteria thrive in such an environment, but rice plants themselves act as gas vents, putting greater-than-expected concentrations into the atmosphere.
• The problem is, of course, magnified by the extension of rice area, by the expansion of irrigation facilities, and especially by the enlargement of double-cropped rice areas.
• Rice fields are suspected of putting 115 million tons of methane into the atmosphere each year.
• This is at least equal to the total production from all of the world’s natural swamps and wet lands.
• Is it possible that agricultural intensification is hastening environmental degradation?
• As a result of Europe’s great Age of Exploration, new lands to the West became available for exploitation.
• Rice cultivation was introduced to the New World by early European settlers.
• The Portuguese carried it to Brazil, and the Spanish introduced its cultivation to several locations in Central and South America.
• The first record for North America dates from 168 B.C.
• The crop may well have been carried to that area by slaves brought from Madagascar.
• Early in the 18th Century, rice spread to Louisiana, but not until the 20th Century was it produced in California’s Sacramento Valley.
• The introduction in the latter area corresponded almost exactly with the time of the first successful crop in Australia’s New South Wales.

The classification of rice cultivated in Indian

Botanical name : Oryza sativa L.

Family : Gramineae

• Domestication of rice ranks as one of the most important developments in history, for this grain has fed more people over a longer period of time than has any other crop.
• The earliest settlements might well have been near the edge of the uplands, on gently rolling topography and close to small rivers that provided a reliable water supply.
• The earliest agriculture was probably focused on plants that reproduced vegetatively, but the seeds of easily shattering varieties of world rice such as Oryja fatuamay have found their way to the gardens at an early date.
• If these assumptions are correct, then domestication most likely took place in the area of Korat or in some sheltered basin area of Northern Thailand, in one of the longitudinal valleys of Maynmar’s Shan Upland, in South-Western China or in Assam.
• Cultivated rices belong to two species, O. sativa and O. glaberrima. Of the two, O. sativa is by far the more widely utilized. O. sativa is a complex group composed of two forms endemic to Africa but not cultivated.
• A third form, O. rufipogon, having distinctive partitions spread into South Asian, Chinese, New Guinean, Australian, and American forms. The sub-division of O. sativa into seven forms began long ago and came about largely as a result of major tectonic events and world wide climatic changes.
• It is postulated, based on measurements by electrophoresis, that all the Australian forms of O. sativa began to diverge from the main forms about 15 million years ago. At that time, during the Miocene, the Asian portion of Gondwanaland collided with the Australia / New Guinea portion, creating a land bridge across which O. sativa migrated.
• Once the blocks separated, the Australian form was free to follow an evolutionary path some what different from that followed by the O. sativa on the main land.
• Divergence between the South Asian and Chinese forms, the ancestors of what are commonly referred to today as indica and japonica (or sinica) types, is believed to have commenced 2-3 million years ago.
• At that time, migration of fauna across the proto-Himalaya was still possible, and with the animals went wild rice. The climate was suitable for rice in what today is Central Asia, and North China.They had almost ideal conditions.
• Botanical evidence concerning the distribution of cultivated species is based chiefly on the range and habitat of wild species that are believed to have contributed to the cultivated forms.
• The greatest variety of such rice is found in the zone of monsoonal rainfall extending from Eastern India through Myanmar, Thailand, Laos, Northern Vietnam and Southern China.
• This diversity of species, including those considered by many to have been involved in the original domestication process, lends support to the argument for mainland South-East Asia as the heartland of rice cultivation.
• The earliest and most convincing archeological evidence for domestication of rice in South-East Asia was discovered by Wilhelm G. Solheim II in 1966.
• Pottery shreds bearing the imprint of both grains and husks of O. sativa were discovered at Non-Nok. Tha in the Korat area of Thailand. These remains have been confirmed by 14C and thermoluminescence testing as dating from at least 4000 B.C.
• Rice, an annual grass belongs to the genus Oryza. There are about twenty three species out of which only two species have been known of their commercial value being used for cultivation. These two species are Oryza sativa (Asian rice) and Oryza glaberrima (African rice).
• The Oryza sativa is the most commonly grown species through out the world to day while Oryza glaberrima is grown only in South Africa.
• In Asia Oryza sativa is differentiated into three sub-species based on geographical conditions, viz., indica, japonica and javanica.
• The variety indica refers to the tropical and sub-tropical varieties grown throughout South and South-East Asia and Southern China.
• The variety japonica is grown in temperate areas of Japan, China and Korea, while javanica varieties are grown along side of Indicas in Indonesia.

Uses of rice

• Rice is primarily a high energy food.
• Rice bran one of the by-products of rice milling is used as cattle and poultry feed.
• Rice hulls can be used in manufacturing insulation materials, cement and card board and as litter in poultry production.
• Rice straw can be used as cattle feed as well as litter during winter reason.
• Rice straw forms a substrate for mushroom production.
• Straw is also used as roofing material in village huts.