Oryza sativa : The most important world rice


Oryza sativa : The most important world rice sepecies

a-Species Oryza sativa L.

+Classification
Kingdom:
Plantae
Division:
Angiosperms
Class:
Monocots
Order:
Poales
Family:
Poaceae
Genus:
Oryza
Species:
Oryza sativa L.
Oryza sativa, commonly known as Asian rice, is the plant species most commonly referred to in English as rice. Oryza sativa is the cereal with the smallest genome, consisting of just 430 Mb across 12 chromosomes. It is renowned for being easy to genetically modify, and is a model organism for cereal biology.
+How many subspecies of Oryza sativa?
+In tradictional classification system, Oryza sativa contains three major subspecies (also called varieties):
-Varieties indica: with the name O. sativa var. indica are the nonsticky, long-grained rice variety also called tropical rice or Asia rice or Indian rice. This variety distributes in the tropical Asia. Now today it is growing in the tropical areas of Asia, Africa, America and Australia.
-Varieties japonica: with the name O. sativa var. japonica (or sinica) 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.
-Varieties javanica: with the name O. sativa var. javanica are broad-grained and thrives under tropical conditions, was identified based on morphology and initially called javanica, but is now known as tropical japonica with the name O. sativa var. tropical japonica. Examples of these varieties 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,  naromatic, 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.
Indeed, revised dating of the origins of the rice tribe Oryzeae have been led to the suggestion that the date might be pushed back as early as 107 Ma to 129 Ma.
On over the world before growing improment rices, there are a bout 40.000 varieties of Oryza sativa , but now almost of them have lost by not be grown.
Rice is known to come in a variety of colors, including: white, brown, black, purple, and red.

b-Distribution of Species Oryza sativa L. on the world

Rice is a major food staple and a mainstay for the rural population and their food security. Rice is vital for the nutrition of much of the population in Asia, as well as in Latin America and the Caribbean and in Africa; it is central to the food security of over half the world population.
Developing countries account for 95 percent of the total production, with China and India alone responsible for nearly half of the world output.
World production of rice has risen steadily from about 200 million tonnes of paddy rice in 1960 to over 678 million tonnes in 2009. The most productive farms for rice, in 2009, were in China producing 6.59 tonnes per hectare.
The three largest producers of rice in 2009 were China (197 million tonnes), India (131 Mt), and Indonesia (64 Mt). At 44 million hectares, India had the largest farm area under rice production in 2009.
The International Grains Council (IGC) now puts world rice production in 2010-11 at 450 million tonnes,
Global rice production in 2011-12 is forecast at a record 457.9 million tonnes.
Today, the majority of all rice produced comes from ChinaIndiaIndonesiaPakistan,BangladeshVietnamThailandMyanmarPhilippines, and JapanAsian farmers still account for 92% of the world's total rice production.
The world rice production reached a new record in 2010, at 464 million tons (696 million tons paddy).
World rice utilization in 2011/12 is forecast to expand by 2.4 percent to 472 million tonnes (milled basis), sustained by an increase in consumption of rice as food, close to 398 million tonnes.
As for food, the average per capita rice consumption is forecast to approach 57 kg in 2012, about 1 percent more than in 2011.
The folowing table shows Area Harvested (ha), Yield (kg/ha) and Total production on the world in 2011:

Areas
Area Harvested (Ha)
Yield
(kg/ha)
Total Paddy rice
(Ton)
World +(Total)
153,652,007
4,373.6
672,015,587
+Africa +(Total)
9,051,788
2,525.0
22,855,318
-Eastern Africa
2,571,816
2,615.6
6,726,891
-Middle Africa
715,537
953.8
682,478
-Northern Africa
473,465
9,300.8
4,403,590
-Southern Africa
1,135
2,647.6
3,005
-Western Afrtca
5,289,835
2,086.9
11,039,354
+America +(Total)
7,308,591
5,085.8
37,170,221
-Northern America
1,462,950
7,537.5
11,027,000
-Central America
332,168
3,799.6
1,262,106
-Caribbean
423,324
3,540.1
1,498,624
-South America
5,090,149
4,593.7
23,382,492
+Asia +(Total)
136,550,500
4,447.6
607,328,408
-Central Asia
241,254
3,410.9
822,904
-Eastern Asia
33,206,936
3,463.4
188,556,290
-Southern Asia
48,511,763
4,141.0
200,887,445
-Western Asia
148,580
6,863.4
1,019,759
+Europe + (Tptal)
717,728
6,190.6
4,443,148
-Eastern Europe
256,503
5,202.5
1,334,448
-Southern Europe
437,425
6,835.9
2,990,200
-Western Europe
23,800
4,979.0
118,500
+Oceania + (Total)
23,400
9,337.3
218,492
-Australia + N. Zealand
19,000
10,842.1
206,000
-Melanesia
4,310
2,861.7
12,334
-Micronesia
90
1,755.6
158

References:
1-Oryza sativa- From Wikipedia, the free encyclopedia
3. IRRI, 2001. Rice Research and Production in the 21st Century.

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