is the seed of the monocot plants Oryza sativa (Asian rice) or
Oryza glaberrima (African rice). As a cereal grain, it is the
most important staple food for a large part of the world's human
population, especially in Asia and the West Indies. It is the
grain with the third-highest worldwide production, after maize
(corn) and wheat, according to data for 2009.
Since a large portion of maize crops are grown for purposes
other than human consumption, rice is the most important grain
with regard to human nutrition and caloric intake, providing
more than one fifth of the calories consumed worldwide by the
There are many varieties of rice and culinary preferences tend
to vary regionally.
Pakistan is home to one of the greatest diversities of both wild
and cultivated crops. It is claimed that around 4,00,000
varieties of rice existed in Pakistan during the Vedic period.
75% of Pakistani rice production comes from 10 rice varieties -
out of 30,000 that existed a few decades ago. Most indigenous
varieties are resistant to pests, require less farm inputs like
fertilizers and pesticides and they yield straw that is valuable
to the farmer as cattle feed and roofing material.
Rice cultivation is well-suited to countries and regions with
low labor costs and high rainfall, as it is labor-intensive to
cultivate and requires ample water. Rice can be grown
practically anywhere, even on a steep hill or mountain. Although
its parent species are native to South Asia and certain parts of
Africa, centuries of trade and exportation have made it
commonplace in many cultures worldwide.
The traditional method for cultivating rice is flooding the
fields while, or after, setting the young seedlings. This simple
method requires sound planning and servicing of the water
damming and channeling, but reduces the growth of less robust
weed and pest plants that have no submerged growth state, and
deters vermin. While flooding is not mandatory for the
cultivation of rice, all other methods of irrigation require
higher effort in weed and pest control during growth periods and
a different approach for fertilizing the soil.