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Wheat plant
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Poales
Family: Poaceae
Genus: Triticum
T. aestivumT. aethiopicum
T. araraticumT. boeoticum
T. carthlicumT. compactum
T. dicocconT. durum
T. ispahanicumT. karamyschevii
T. militinaeT. monococcum
T. polonicumT. spelta
T. timopheeviiT. trunciale
T. turanicumT. turgidum
T. urartuT. vavilovii
T. zhukovskyi
ITIS 42236 2002-09-22
Wheat (Triticum spp) is a grass that is cultivated around the world. Globally, it is the second-largest cereal crop, tied with maize; the third being rice. Wheat grain is a staple food used to make flour, as livestock feed and for brewing beer. Wheat is also planted strictly as a forage crop for livestock and hay.

It is thought that wheat was first domesticated in the Fertile Crescent area of the Middle East.

Table of contents
1 Varieties
2 Production and consumption statistics
3 Agronomy
4 Economics
5 Wheat in the United States
6 See also
7 External links


Wheat varieties are classified by growing season (winter wheat vs. spring wheat) and by gluten content (hard wheat (high gluten content) vs. soft wheat (high starch content)).

Major varieties of wheat

Production and consumption statistics

In the 2002 crop year, international wheat production totalled 563.2 million tons and the top wheat producing countries were:

  1. China: 89 million tons
  2. India: 71.5 million tons
  3. Russian Federation: 50.6 million tons
  4. United States: 44 million tons
  5. France: 39 million tons
  6. Canada: 15.7 million tons

1997 global per capita wheat consumption was 101 kg, led by Denmark at 623 kg.

Past international wheat production statistics.


Crop development

Crop management decisions require the knowledge of stage of development of the crop. In particular, spring fertilizers applications, herbicides, fungicides, growth regulators are typically applied at specific stages of plant development.

For example, current recommendations often indicate the second application of nitrogen be done when the ear (not visible at this stage) is about 1 cm in size (Z31 on Zadok scale). Knowledge of stages is also interesting to identify periods of higher risk, in terms of climate. For example, the meļosis stage is extremely suceptible to low temperatures (under 4°C) or high temperatures (over 25°C). Farmers also benefit from knowing when the flag leaf (last leaf) appears as this leaf represents about 75% of photosynthesis reactions during the grain filling period and as such should be preserved from disease or insect attacks to insure a good yield.

Several systems exist to identify crop stages, with the Feekes and Zadoks scales being the most widely used. Each scale is a standard system which describes successive stages reached by the crop during the agricultural season.

Wheat stages


Wheat is subject to more diseases than other grains, and, in some seasons, especially in wet ones, heavier losses are sustained from those diseases than are felt in the culture of any other culmiferous crop with which we are acquainted. Wheat may suffer from the attack of insects at the root; from blight, which primarily affects the leaf or straw, and ultimately deprives the grain of sufficient nourishment; from mildew on the ear, which operates thereon with the force of an apoplectic stroke; and from gum of different shades, which lodges on the chaff or cups in which the grain is deposited.

Examples of wheat diseases:

Bacterial disease

Fungal diseases Nematodes, parasitic Viral diseases and viruslike agents Phytoplasmal diseases


Harvested wheat grain is classified according to grain properties (see below) for the purposes of the commodities market. Wheat buyers use the classifications to help determine which wheat to purchase as each class has special uses. Wheat producers determine which classes of wheat are the most profitable to cultivate with this system.

Wheat is widely cultivated as a cash crop because it produces a good yield per acre, grows well in a temperate climate even with a moderately short growing season, and yields a versatile, high-quality flour that is widely used in baking. Most breads are made with wheat flour, even many breads named for the other grains they contain, including most rye and oat breads. Many other popular foods are made from wheat flour as well, resulting in a large demand for the grain even in economies with a significant food surplus.

Wheat in the United States

Classes used in the United-States are

Hard wheats are harder to process and red wheats may need bleaching. Therefore, soft and white wheats usually command higher prices than hard and red wheats on the commodities market.

Much of the following text is taken from the Household Cyclopedia of 1881:

Wheat may be classed under two principal divisions, though each of these admits of several subdivisions. The first is composed of all the varieties of red wheat. The second division comprehends the whole varieties of white wheat, which again may be arranged under two distinct heads, namely, thick-chaffed and thin-chaffed.

The thick-chaffed varieties were formerly in greatest repute, generally yielding the whitest and finest flour, and, in dry seasons, not inferior in produce to the other; but since 1799, when the disease called mildew, to which they are constitutionally predisposed, raged so extensively, they have gradually been going out of fashion.

The thin-chaffed wheats are a hardy class, and seldom mildewed, unless the weather be particularly inimical during the stages of blossoming, filling, and ripening, though some of them are rather better qualified to resist that destructive disorder than others. In 1799, thin-chaffed wheats were seriously injured; and instances were not wanting to show, that an acre of them, with respect to value, exceeded an acre of thick-chaffed wheat, quantity and quality considered, not less than fifty per cent. Since that time, therefore, their culture has rapidly increased; and to this circumstance may, in a great measure, be attributed the high character which thin-chaffed wheats now bear.

See also

External links