The Evolution of Wheat - Bread Wheat

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For many years, it was believed that Bread Wheat had evolved from Spelt by mutations that changed the form of the ear. Newer scientific research now suggests that it evolved independently about 8,500 years ago but from the same two ancestors, Cultivated Emmer and a Goat Grass. This created a free-threshing hybrid that differed from Spelt by the ear being roughly square in section, with more grains and a tougher rachis. The grain was also enclosed by a softer shell that would break away easily when threshed to release the grains. After further evolution, it became the source of the hexaploid Bread Wheat, Triticum aestivum.

Initially the farmers grew wheat from seed they had saved from the harvest of the previous year. Over many years, this created different "landraces", each being a selection of wheat suited to the type of soil or area where it had developed. By using selected landraces and hybridisation, wheat breeders have created and developed many improved varieties of wheat. Selected reduced-height genes have been introduced into wheat varieties to produce plants that use photosynthesis to increase the grain yield instead of the plants growing taller. In Britain, this gave an increase in yield from about 500 kg/ha in the 1300's, up to 1,000 kg/ha in the 1800's,  2,000 kg/ha by 1914, and up to 8,000 kg/ha in 2000 using newer varieties.