Agricultural Uses
Wheat, along with rice and corn, forms one of the most
extensively available foods grown in a wide variety of
regions of the world.
Wheat is believed to have been in existence for over
a few thousand years, and originated in and around Iran,
Iraq and Turkey.
Wheat is a member of the grass family. The plant
grows to a height of around a meter and has narrow green
leaves. When wheat seeds germinate, they develop a
seminal root system. The first leaf, protected by the
coleoptile, is thrust through the soil upwards. As other
leaves develop, the plant grows in height. At the base of
each leaf is a bud which can develop into a tiller. Each
tiller can develop into a mature stem which holds the
wheat head. The latter contains seeds edible for humans.
The kernel, or the seed, is divided into three parts:
the endosperm, the bran and the germ (embryo). The
endosperm constitutes over 80% of the seed, and is rich
in protein (gluten being an important component),
carbohydrates, iron and Vitamin B (riboflavin, niacin
and thiamine). Bran constitutes 15 % of the kernel weight
and holds Vitamin B, fiber, Mg, Zn, Mn, folic acid and
protein. Whole wheat flour contains bran. The germ,
which has high quality protein, accounts for 2% of the
kernel weight, and is also present in whole wheat flour.
Foods made out of whole wheat have more vitamin, fiber
and proteins.
Ideal conditions for wheat cultivation are temperate
grasslands with 30 to 90 cm of rain and relatively cool
temperatures, especially during its early growing stages.
During the later stages, the kernel growth is encouraged
by sunny days.
Today, wheat is grown in many parts of the world.
USA, China, the erstwhile USSR and India being the
prime producers. India, for instance, produces about
12% of the world wheat.
The modem wheat, as we know it today, is the
natural cross between the Triticum spp and the goat grass
(Aegilops spp). The Triticum monococcum or the einkorn
wheat is believed to have been the first to be cultivated.
This later evolved into emmer wheat.
Over years of hybridization, bread wheat (Triticum
aestivum) and durum wheat (Triticum turgidum) are now
widely cultivated.
Wheat is used in the making of bread, pastries,
breakfast cereal, spaghetti, noodles, pasta, sauces,
gravies, etc. These and other wheat products are high in energy and low in fat. But in the process of refining, the
bran chaff and the germ are removed, leaving behind only
starch in the final product.
There are two crops of wheat worldwide. One is the
winter wheat (Sept-Oct) and the other is the spring
wheat (mid-May). Wheat that is grown in limited rainfall
areas is called hard wheat. It has a higher protein
content. Adequate rainfall favors soft wheat which has a
lesser protein content.
The need to increase the yield per hectare has
encouraged research in biotechnology, plant breeding
and genetic engineering. These initiatives have opened up
a few areas of conflicting view-points which seem to have
ethical and moral overtones.
Wheat is prone to many foliar-, soil- and seed-borne
diseases throughout its growth. Many fungal, viral and
bacterial diseases affect wheat yields worldwide. Rust
diseases (leaf rust and stem rust), loose smut, powdery
mildew, take-all, etc. affect almost all areas. Fungal
diseases are categorized on the part of the affected plant,
and thus, there are leaf and stem pathogens (like rusts,
mildew) and seed related pathogens (like smut and bunts
diseases).
Rust disease which is a fungal disease, is of two
kinds, namely, leaf rust and stem rust. Leaf rust is
caused by Puccinia recondita tritici and is more common
and destructive than stem rust, caused by Puccinia
graminis tritici. Leaf rust may cause up to 50% of the
yield loss, if infection is not controlled in time. The
spread of rust occurs in late winter or early spring. The
fungi causing the rust disease go through several spore
stages in their life cycle and some of the stages are
completed on alternate or collateral hosts. Humid and wet
conditions, with warm temperatures, favor infection
which spreads as strong winds transport the spores.
Since wheat is grown in large areas throughout the
world, there may be peculiar management practices
prevalent under specific local conditions. However,
broadly, there are some recommended practices such as
crop rotation, planting management, crop residue
management, volunteer wheat, nitrogen management and
wheat varieties - which can yield a healthy crop.
The twin objectives of farmers and researchers alike
have been to increase productivity of crops, and control
the losses by diseases. There are two approaches toward
achieving high yields in environment friendly conditions
from the same plot of land: organic farming, and
conventional farming with the use of chemical fertilizers.
Both approaches have yielded expected results.
Conventional farming methods include the incorporation
of synthetic fertilizers and the use of genetically modified
varieties of wheat by customizing land races of a plant to
suit the local conditions. Such varieties can result into
cultivars exhibiting favorable properties of early
maturity, heat tolerance, etc. Many research stations,
established worldwide, develop seed banks and preserve
germplasm for plant breeding, to produce robust,
disease-resistant and high yielding varieties. There are many research institutes that focus on the objective of
developing modem wheat cultivars.
Organic farming is cultivation of a crop without the
use of synthetic fertilizers. Organic farmers rely on the
use of naturally available sources of minerals for
supplying nutrients to crop.