Rice

Description

Rice is a glabrous annual plant with Chaume (the Paille) drawn up or spread out variable height, of less than one meter up to two meters, even up to five meters for floating rices. It is a plant predisposed with the Tallage, forming a bouquet of Tige S, with fasciculées roots. The flowers, in épillets uniflorous, are grouped in Panicule S from 20 to 30 cm, are drawn up or hanging. The Fruit is a Caryopse wrapped in two Glumelle S large, coriaces and adherent, the unit forming the Paddy. The density of in bulk believed white rice is of approximately 0.9g/cm³.

According to the texture of the caryopse, one distinguishes the varieties:

ordinary, with white tegument, generally, or red;
glutinous (or sticky rice, sweet rice ).

The varieties of African rice are generally with red tegument.

Botanical origin

Rices belong to the kind Oryza L. which includes/understands more than one score of Espèce S, of which two are cultivated:

Oryza sativa L., originating in the Asia, it is cultivated the most;
Oryza glaberrima Steud., rice African or rice of Casamance, originating in central Africa.

Oryza sativa comes from various events of domestication having taken place approximately 5000 years front J. - C. in India of North, and around the border sino-Burmese. The wild relative of cultivated rice is Oryza rufipogon (in the past, the annual forms of Oryza rufipogon were named Oryza will nivara ). With not confusing with rice named wild Rice of botany Zizania.

Oryza glaberrima comes from the domestication of Oryza barthii . One does not know where domestication took place, but it seems to go back to before 500 av. J. - C.. Since a few tens of years, this rice is less and less cultivated in Africa where Asian rice is preferred to him more and more. Today, of the hybrid varieties sativa - glaberrima combining qualities of the two species is diffused under the name Nérica .

Varietal classification

Cultivated rice exists in very many varieties, several thousands, which were classified historically in three groups: japonica with épillet short, indica with épillet very long, and an intermediate group in the past named javanica .

Today, one classifies Asian rice in two subspecies, indica and japonica , on molecular bases, but also of reproductive incompatibility. These two groups correspond to two events of domestication having taken place on both sides the Himalayas. Named in the past rices " javanica " belong to the group japonica . One speaks sometimes about “ japonica tropical”.

The subspecies indica gathers traditional indica , scented rices long grain (basmati and sadri), the rices adapted to the “dry” culture (without flood of the field) and of the floating ecotypes. The subspecies japonica gathers the japonica moderate and tropical (ex- javanica ), the ecotypes “aus”, and of the floating ecotypes.

The thousands of existing varieties of rice are sometimes classified according to their degree of precocity, according to the length of the vegetative Cycle (on average 160 days). One speaks then about varieties very early (90 to 100 days, écoptypes “aus”), early, semi-early, late, very late (more than 210 days). This mode of classification, if it is practical from an agronomic point of view, does not have any taxonomic value however.

The “wild Riz” belongs to a nearby kind: the Discord ( Zizania aquatica L., originating in the North of the the United States and the Canada).

Species

100.000 existing varieties of rice today are counted|date= November 17th, 2007 .

The kind Oryza includes/understands a score of different species. Many classifications of these species in complexes, tribes, series, etc were proposed, and recut the one more or less the others. Classification suggested here has the advantage of being simple, and resumes the most recent work. The base as of these classifications is the organization of the genome (Ploïdie, level of homology of the genomes, etc), but is coherent with the morphological characteristics observed at these various species.

Complex sativa . In this group the two rice species are found cultivated, their wild parents, and of the close species.

Oryza sativa Flax., Asian cultivated rice.
Oryza sativa F. spontanica auct.
Oryza rufipogon Griff., is the relative supposed of the cultivated species Oryza sativa , Asian rice. Certain individuals of this species are annual plants, others are perennial. Traditionally, the annual form of Oryza rufipogon was named Oryza will nivara . This name of species should not be used any more today, because the annual and perennial forms are completely interfertiles, and do not form two distinct populations. In order to remove any ambiguity, one writes sometimes Oryza rufipogon sensu lato to indicate this species in his new meaning on the perennial form, on the annual form (ex- Oryza will nivara )
Oryza meridionalis Ng.
Oryza glumaepatula comes from South America. This species cannot be distinguished from Oryza rufipogon on a morphological basis. However, it is indeed a different species because the plants d' Oryza glumaepatula and d' Oryza rufipogon are not interfertiles.
Oryza glaberrima Steud., the rice of Casamance. It was probably domesticated in West Africa starting from the annual wild species Oryza barthii . Oryza glaberrima is cultivated only in West Africa (Senegal until the Lac Chad) whereas Oryza barthii is present in East Africa (Tanzania) and southern (Zambia).
Oryza barthii A. Chev., probable wild relative of the rice of Casamance ( Oryza glaberrima ). This species also exists in the form of Adventice S of which some were historically named Oryza stapfii A. Chev. One also finds in the literature the name Oryza breviligulata which is synonymous with Oryza barthii .
Oryza longistaminata Chev. & Roch.

Complex officinalis . This other great group gathers species with L `more diversified ecology: one finds species pushing with the sun in flooded zones in a permanent or temporary way, but also of the species pushing in underwood, or in nonflooded zones.

Oryza officinalis Wall.
Oryza minuta Presl
Oryza rhizomatis Vaughan, is limited to the island of Ceylon (Sri Lanka).
Oryza eichingeri Peter
Oryza punctata Kotschy ex Stend.
Oryza latifolia Beauv.
Oryza Alta Swallen
Oryza australiensis Domin
Oryza grandiglumis (Gift.) Prod.

Two other smaller groups of many species are described in the literature:

Complex ridleyi

Oryza ridleyi Hook. F.
Oryza longiglumis P. Jansen

Complex granulata

Oryza granulata Born.
Oryza neocaledonica Morat, a species close to Oryza granulata which pushes only in New Caledonia (endemic species ).
Oryza meyeriana (Zoll. & My.) Baill

Lastly, the two following species are gathered with no other:

Oryza schlechteri Pilqer - This species is close to the complex ridleyi , but would not form part of it.
Oryza brachyantha Chev. is completely independent.

History

The Homme started to cultivate rice there is close to 10 000 years at the time of the Neolithic revolution . It develops initially in China then in the rest of the world. Oryza rufipogon , from which is derived cultivated rice, exists since less than 680.000 years.

Rice was known old Greek S since forwardings of Alexandre Large the in Perse.

Rice is mentioned as of 1393 in France, in Mesnagier of Paris , but it is still a product of importation. They are the Moslem which introduces it in Spain. In Italy, it appears in 1468. In France, attempts at cultures are carried out at the 17th century, but it is only in second half of the 20th century that this culture develops, parallel to the installation of the delta of the the Rhone.

Culture

Nearly 2000 varieties of rice are cultivated today but especially, one counts several names of them:

the paddy in a rough state,
the cargo liner or brown rice ,
the white rice at the time of its last phase.

Generally, 1 Kilogram of rice paddy gives 750 G of rice cargo liner and 600 G of white rice . The difficulties related to the culture of rice make that contrary to corn, it is cultivated in very little country. Thus, nearly 90% of the worldwide production is provided by Asia of the Mousson S. Alone, the total productions added with the China and of the India exceed half of the worldwide production. That is explained in particular by the requirements of matter rice Climat ic and human.

Indeed, the needs for the plant in heat, moisture and light are very specific. It is only in the tropical and subtropical areas that rice can be cultivated all the year. The luminous intensity required limits its production to the zones being between the parallel 45e northern and the 35e parallel South while the necessary conditions pedological S prove more flexible, the plant being relatively accommodating. The culture of rice requires an important moisture however: the needs rise to at least 100 mm of water per month.

Rice thus involves strong a domestic Consommation out of water.

To all these climatic obstacles the difficulty to Récolte R rice is added. There does not exist equivalent for rice with the reaping-machine used for the Blé. Harvest thus or is not automated very little, which requires a important Labor human. By this aspect, the rice perhaps considered as a culture of poor countries, so much the costs in human capital plays a paramount role.

Rice growing irrigated requires plane surfaces, canals irrigation, ground liftings. In mountainous area, this type of culture is sometimes practiced in terrace S. Moreover, the Plantule S of rice are initially obtained under Pépinière before being mended under a water blade in a ground plowed beforehand. On the long run, maintenance poses also serious problems because it requires Sarclage and Désherbage of the ground before carrying out harvest with the obligatory Faucille and whose outputs prove to be weak. This mechanism is that of rice the culture known as intensive because having the best outputs and allowing several harvests per annum (up to three in the delta of the Mekong).

Flooded rice growing is practiced in naturally flooded zones in a periodic way. In this category two types of culture are included, one at a shallow depth, and comparable in less controlled with the irrigated culture, the other with strong depth (sometimes more than one meter) or particular varieties of rice (known as “floating”) is cultivated. Sometimes, there exist intermediate situations or the level of flood is partially controlled.

There exists also a rice growing known as rain . Rice is not cultivated “the feet in water” and does not require an irrigation uninterrupted. This type of culture can meet in the tropical zones of West Africa. These extensive cultures or dry are still practiced, but offer weaker outputs.

Plant health protection of rice

The plant health protection of rice is regulated, in particular in France.

Production

These last years, the rise of the production of rice was especially due to the rise of the outputs, but a relative stagnation of the latter is lately noted (approximately 38 quintals by Hectare). The general production of rice fluctuates less than that of the Blé, of the fact in particular of the least economic issues and policies.

In 2003, the worldwide production of rice paddy rose to 585 million tons (source: FAO).

Forecasts 2005

The forecasts for 2005 announce a world raising of prices, vis-a-vis a request with the rise. In 2004, Thai price of one tonne of rice the “100% rank B” varied between 250 and 270 dollars, the price of the ton of this same rice should range between 325 and 350 dollars in 2005.

The independent factors of production will be for 2005:

reappearance awaited of the climatic phenomenon “El Niño” which always has a harmful impact on the rice reproduction, while bringing the dryness on the South-East Asia;
of world stocks to low: at the end of 2004, they are with half of those of the year 2000;
trend production drops some in the majority of the exporting countries, except for the the United States;
big raise of the world demand.

Exporting countries

Seulement 4% of the annual worldwide production, which borders the 600 million tons, is intended for the international business. This one is in growth of 7% per year.
the the United States will become in 2005 the first world exporter with 10,1 MT.
the Thailand was the first world exporter in 2004: 7,58 MT (2003) - 10,13 MT (2004) - 8,5 MT (2005 envisaged.).

rice “Hom Mali”, subtly scented like the white flower of the Jasmine, account for 25% of exports, bringing back some 2,5 million dollars per year to the country with approximately 550 dollars the ton, against 250 dollars for white rice. A million small farmers in the North-East of the country, area known under the name of Isan, must be generally satisfied with a monthly income of hardly 200 dollars and live largely below the threshold of precariousness depending on the Mousson.

the Vietnam is the second exporter: 3,9 MT (2004) - 3,8 to 4,0 MT (2005 envisaged.)
the India was the second exporter in 2002: 6,7 MT (2002) - 4,3 MT (2003) - 2,8 MT (2004) - 1,3 to 1,4 MT (2005 envisaged.)
Taiwan takes part in operations of assistance per distribution of rice.

Importing countries

Filipino : 0,985 MT (2004) - 1,1 MT (2005 envisaged.).
the China: the country has an enormous evaluated rice stock with 42 MT, however its forecasts of purchases carry on 0,7 MT (2005 envisaged.)

Use

For the food

Some dishes containing rice:

Curry (Island of the Meeting)
Rice pudding
Mochi (Japan)
Paella (Spain)
Risotto
Cantonese Rice (China)
Plov (Ouzbékistan and Xinjiang (China))
Thieboudienne (Senegal)
Nasi padang (Indonesia)

For health

The rice and its water of cooking are completely effective to help to fight against the diarrheas.

Rice and the GMO

See also: Organization genetically modified

According to the review Science , the China, first producer country and consuming rice, plans to market rices GMO in the short run, i.e. since 2006. They are two varieties resulting from Chinese research, resistant to the Pyrale of rice thanks to transplanted genes, one of the Bacillus thuringiensis (rice Xianyou 63) and the other of a plant, the Dolique in black eye (rice Youming 86). These varieties were the subject of culture in real conditions in 2001 and 2003. These tests showed the signficant reduction of the consumption of pesticides (80%) with a positive effect on health of the farmers and their economic results, and an improvement of the output (63,6 q/ha against 61,5 for traditional varieties). However, no scientific study still showed the harmlessness of these products GMO on the human body, nor their harmfulness besides. China is already largest cotton producer GMO, but with rice, it would be the second time that products GMO would be put massively on the market of the human consumption (after soya).

In addition, following the presence of GMO in Chinese Noodles distributed by Tang Brothers, discovered in September 2006, China denied to have authorized the culture of genetically modified organizations.

Case of gilded rice

The “Rice gilded” or “ Golden Rice ” is a whole of rice lines which were obtained by transgénèse by a research team Swiss carried out by the P Potrykus in Zurich, in collaboration with a German team directed by the P Beyer in Freiburg. The character " doré" of these lines is due to their transformation with various genes coding a whole of enzymes allowing biosynthesis β- Carotène to take place in the grain of rice. The human organism is able to transform β-carotene into Vitamine has. According to these researchers, “gilded rice” could be an answer to the distress of a half-million people who each year lose the sight, and of one to two million people who, each year, die of deficiency in this vitamin. This work was resumed by the IRRI, which currently works to integrate these transgenes in many news varieties adapted to the various conditions of culture of rice. Within this framework, the character " doré" was transferred to IR64, one of the most used varieties rice indica . The lines obtained kept all caracteric relationship variety, and do not contain genes markers of resistance to antibiotics.

Controversies related to gilded rice

Many groupings ecologists (whose Greenpeace and Friends off the earth) as of the groupings altermondialist S criticized this work and emitted fears concerning their application.

For the activist Vandana Shiva, but also according to other opponents with the GMO, like the international association Greenpeace, it is the approach even which is to be re-examined, the deficiencies in vitamin has are consequences of the Monoculture founded by the Green revolution, the solution resides according to it in the restoration of the Biodiversité. In addition, Greenpeace association showed that the β-carotene amounts found in the first gilded rice lines were very low. He was said by militants of this association that very great quantities (of 4 has 18 kilos according to the sources) of gilded rice were to be consumed each day to obtain the daily Apport recommended (AJR) in vitamin A. Cependant, the recent gilded rice lines produce greater quantities of vitamins has (23 times more than the first), and a daily consumption much more modest makes it possible to provide the amounts of vitamin has desirable.

The people and the organizations at the origin of this technique (particularly Ingo Potrikus and the Foundation Rockefeller) defended, sometimes with vehemence the interest of this novel method for health in the countries in the process of development. Two axes of argumentation were developed: on the one hand, there would not exist reasonable scenario leading to a serious risk for the environment; and D `another share, the people currently suffering from Avitaminose has are reached in spite of the programs of fight existing against this deficiency. Gilded rice would be added, and would not replace, the existing programs.

Many mediae carried out reports reporting the controversy related to gilded rice for example.

Climate warming

The intensive culture of rice contributes to the Climate warming. It is at the origin of the emission of a rather large quantity of Méthane, powerful Gaz with greenhouse effect.

As rice growing, two types of bacteria act: the anaerobic bacteria develop in the absence of oxygen; the bacteria Aérobie S develop in the presence of oxygen. The anaerobic bacteria produce methane, and the aerobes consume some. The techniques of irrigation usually used for rice growing support the principal development of the anaerobic bacteria, therefore the production of methane only is absorbed very little by the aerobic bacteria. Consequence, a great quantity of methane is produced and released in the atmosphere. Alternative techniques of irrigation could however be used to limit this problem.

The production of one kilo rice corresponds to the emission of 120 G. of Methane. Rice growing represents of this fact the second world producer of Méthane with 60 million tonnes/an; just behind the breeding of the ruminants which him génêre 80 million tonnes/an.

See too

Random links:

Cartigny (Geneva) | Tournament of the six nations 2006 | Aizuwakamatsu | National missile defense | Nogegon