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
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
The three
largest producers of rice in 2009 were China
(197 million tonnes), India
(131 Mt), and Indonesia India
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 China , India , Indonesia , Pakistan ,Bangladesh , Vietnam , Thailand , Myanmar , Philippines ,
and Japan
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
|
+
|
9,051,788
|
2,525.0
|
22,855,318
|
-Eastern
|
2,571,816
|
2,615.6
|
6,726,891
|
-Middle
|
715,537
|
953.8
|
682,478
|
-Northern
|
473,465
|
9,300.8
|
4,403,590
|
-Southern
|
1,135
|
2,647.6
|
3,005
|
-Western Afrtca
|
5,289,835
|
2,086.9
|
11,039,354
|
+
|
7,308,591
|
5,085.8
|
37,170,221
|
-Northern
|
1,462,950
|
7,537.5
|
11,027,000
|
-
|
332,168
|
3,799.6
|
1,262,106
|
-
|
423,324
|
3,540.1
|
1,498,624
|
-
|
5,090,149
|
4,593.7
|
23,382,492
|
+
|
136,550,500
|
4,447.6
|
607,328,408
|
-Central
|
241,254
|
3,410.9
|
822,904
|
-Eastern
|
33,206,936
|
3,463.4
|
188,556,290
|
-Southern
|
48,511,763
|
4,141.0
|
200,887,445
|
-Western
|
148,580
|
6,863.4
|
1,019,759
|
+
|
717,728
|
6,190.6
|
4,443,148
|
-
|
256,503
|
5,202.5
|
1,334,448
|
-Southern
|
437,425
|
6,835.9
|
2,990,200
|
-
|
23,800
|
4,979.0
|
118,500
|
+
|
23,400
|
9,337.3
|
218,492
|
-
|
19,000
|
10,842.1
|
206,000
|
-
|
4,310
|
2,861.7
|
12,334
|
-
|
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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