Rice (Oryza sativa) is the major food crop in the world. Nearly 40% of the
world population consumes rice as the major staple food. Most of the people,
who depend on rice as primary food, live in the less developed countries.
Archeological evidence on rice in India dates back to 1500-1000 B.C. Since the
dawn of civilization, rice has served humans as a life-giving cereal in the humid
regions of Asia and, to a lesser extent, in West Africa. Introduction of rice into
Europe and the America has led to its increased use in human diets. There are
42 rice producing countries throughout the world but China and India are major
rice production centers. Rice is grown in wide range of agro-climatic conditions
ranging from mountainous (Jammu) lands to low land delta areas (Sundarban),
spanning an area from 53° latitude north to 35° south of the world but about
90% of the crop is grown and consumed in Asia. Rice provides fully 60% of the
food intake in Southeast Asia and about 35% in East Asia and South Asia. The
highest level of per capita rice consumption (130-180 kg per year, 55-80% of
total caloric source) takes place in Bangladesh, Cambodia, Indonesia, Laos,
Myanmar (Burma), Thailand, and Vietnam (Kenneth and Kriemhild, 2000). In
many cultures of the world rice is the central part of people’s life and culture.
Rice is an excellent food and is an excellent source of carbohydrates and energy.
During last 50 years, world rice area has increased by 1.37 times from
115.50 to 159 m ha but production has increased three times from 216 to 685 mt
and productivity has increased 2.3 times from 1.87 t/ha to 4.30 t/ha (Fig. 4.1).
China is the world’s leading rice producer with nearly 125 million tones
production. India possess largest rice area (45 m ha) producing nearly a quarter
of Asia’s production occupying second position after China (Moya et al., 2004).
In India, Rice production and productivity showed a steady increase from the
first five year plan to the tenth five year plan (Fig. 4.2). Rice production has
been increased during last six decades by nearly 481% or 4.8 times from 20.58
mt in 1950-51 to nearly 99.15 mt during 2008-09, whereas the average rice
productivity has been increased 3.3 folds from 668 kg/ha in 1950-51 to 2186
kg/ha in 2008-09 (Table 4.1).
production will have to grow by almost a billion tonnes. Crop yields will grow
but at a slower rate than in the past. Although rice commands a higher price
than wheat on the international market, less than 5% of the world’s rice enters
that market, contrasted with about 16% of the wheat. On the basis of mean
grain yield, rice crops produce more food energy and protein supply per hectare
than wheat and maize. Hence, rice can support more people per unit of land
than the two other staples (Lu and Chang, 1980). It is, therefore, not surprising
to find a close relationship in human history between an expansion in rice
cultivation and a rapid rise in population growth (Chang, 1987).
As a human food, rice continues to gain popularity in many parts of the
world where other coarse cereals, such as maize, sorghum and millet, or tubers
and roots like potatoes, yams, and cassava have traditionally dominated. For
example, of all the world’s regions, Africa has had the sharpest rise in rice
consumption during the last few decades. Rice is unquestionably a superior
source of energy among the cereals. The protein quality of rice (66%) ranks
only below that of oats (68%) and surpasses that of whole wheat (53%) and of
corn (49%). Milling of brown rice into white rice results in a nearly 50% loss of
the vitamin-B-complex and iron and washing milled rice prior to cooking further
reduces the water-soluble vitamin content. However, the amino acids, especially
lysine, are less affected by the milling process (Kik, 1957; Mickus and Luh 1980;
Rice, which is low in sodium and fat and is free of cholesterol, serves as an
aid in preventing hypertension. It is also free from allergens and now widely
used in baby foods (James and McCaskill, 1983). Because rice flour is nearly
pure starch and free from allergens, it is the main component of face powders
and infant formulas. Its low fibre content has led to an increased use of rice
powder in polishing camera lenses and expensive jeweler. Rice starch can also
serve as a substitute for glucose in oral rehydration solution for infants suffering
from diarrhoea (Juliano, 1985b). The coarse and silica-rich rice hull is finding
new use in construction materials. Rice straw is used less in rope and paper
making industries than before, but except for modern varieties, it still serves as
an important cattle feed throughout Asia.
In industrial usage, rice is also gaining importance in the making of infant
foods, snack foods, breakfast cereals, beer, fermented products, and rice bran
oil, and rice wine remains a major alcoholic beverage in East Asia.
On the research front, rewards can be gained by breaking the yield ceiling,
making pest resistance more durable, and improving the tolerance to
environmental stresses. Biotechnology will serve as a powerful force in
broadening the use of exotic germplasm in Oryza and related genera (Chang
and Vaughan, 1991). We also need the inspired and concerted teamwork of
those various sectors of society that, during the 1960s and 1970s, made the
“Green Revolution” an unprecedented event in the history of agriculture.