wheat

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History

The first cereal known to have been domesticated, wheat originated in southwest Asia in the area known as the Fertile Crescent.

The cultivation of wheat began to spread beyond the Fertile Crescent during the Neolithic period. Yields of wheat continued to increase, as new land came under cultivation and with improved agricultural husbandry involving the use of fertilizers, threshing machines and reaping machines (the 'combine harvester'), tractor-draw cultivators and planters, and better varieties (see green revolution and Norin 10 wheat).

Genetics and breeding

Wheat genetics is more complicated than that of most other domesticated species. emmer and durum wheat) are derived from wild emmer, T. Either emmer or durum wheat hybridized with yet another wild diploid grass (Aegilops tauschii) to make the hexaploid (6 chromosomes) wheats, spelt wheat and bread wheat.

Heterosis or hybrid vigor (as in the familiar F1 hybrids of maize) occurs in common (hexaploid) wheat, but it is difficult to produce seed of hybrid cultivars on a commercial scale as is done with maize because wheat flowers are complete and normally self-pollinate. F1 hybrid wheat cultivars should not be confused with standard method of breeding inbred wheat cultivars by crossing two lines using hand emasculation, then selfing or inbreeding the progeny many (ten or more) generations before release selections are identified to released as a variety or cultivar.

Hulled versus free-threshing wheat

Four wild species of wheat, and in the domesticated einkorn, emmer and spelt wheats are hulled (in German, Spelzweizen). In contrast, in free-threshing (or naked) forms such as durum wheat and common wheat, the glumes are fragile and the rachis tough.

Naming

There are many taxonomic classification systems used for wheat species, discussed in a separate article on Wheat taxonomy. It is good to keep in mind that the name of a wheat species from one information source may not be the name of a wheat species in another.

Within a species, wheat cultivars are further classified by growing season, such as winter wheat vs. spring wheat, by gluten content, such as hard wheat (high protein content) vs.

Major cultivated species of wheat

Economics

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 unit area, 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.

Costs and Returns

In Western Europe target wheat yields attainable are around 8 tonnes / hectare. Until recently a tonne of wheat was worth around 90 euros / tonne, giving a total income of 630 euros per hectare for an average yield of 7 tonnes / hectare.

The recent world price rises (2006) for wheat as a commodity could bring in as much as 400 euros per hectare extra for producers.

Organic wheat typically halves yield attainable but costs less as there are no fertiliser and pesticide costs.

Production and consumption statistics

In 1997, global per capita wheat consumption was 101 kg, with the highest per capita consumption (623 kg) found in Denmark.

See also International wheat production statistics.

Agronomy

Crop development

While winter wheat lies dormant during a winter freeze, wheat normally requires between 110 and 130 days between planting and harvest, depending upon climate, seed type, and soil conditions.

Wheat is the most widely used cereal

Wheat stages

Diseases

Estimates of the amount of wheat production lost owing to plant diseases vary between 10-25% in Missouri.

Main article: Wheat diseases

Pests

Wheat is used as a food plant by the larvae of some Lepidoptera species including The Flame, Rustic Shoulder-knot, Setaceous Hebrew Character and Turnip Moth.

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.

Thick-chaffed wheat varieties were the most widely used before 1799, as they generally make the best quality flour, and in dry seasons, equal the yields of thin-chaffed varieties.

Wheat as a symbol

Wheat is also used as a symbol, mostly the symbol of the working class.