Vavilov center

Locating the origin of crop plants is basic to plant breeding. This allows one to locate wild relatives, related species, and new genes (especially dominant genes, which may provide resistance to diseases). Knowledge of the origins of crop plants is important in order to avoid genetic erosion, the loss of germplasm due to the loss of ecotypes and landraces, loss of habitat (such as rainforests), and increased urbanization. Germplasm preservation is accomplished through gene banks (largely seed collections but now frozen stem sections) and preservation of natural habitats (especially in centers of origin). ==Vavilov centers==

and its spread in prehistory as understood in 2003: the Fertile Crescent (11,000 BP), the Yangtze and Yellow River basins (9,000 BP) and the New Guinea Highlands (9,000–6,000 BP), Central Mexico (5,000–4,000 BP), Northern South America (5,000–4,000 BP), sub-Saharan Africa (5,000–4,000 BP, exact location unknown), eastern North America (4,000–3,000 BP). A Vavilov center (of diversity) is a region of the world first indicated by Nikolai Vavilov to be an original center for the domestication of plants. For crop plants, Vavilov identified differing numbers of centers: three in 1924, five in 1926, six in 1929, seven in 1931, eight in 1935 and reduced to seven again in 1940. Vavilov argued that plants were not domesticated somewhere in the world at random, but that there were regions where domestication started. The center of origin is also considered the center of diversity. Schery (1972) and Janick (2002) Vavilov centers are regions where a high diversity of crop wild relatives can be found, representing the natural relatives of domesticated crop plants. Purugganan and Fuller (2009) ==See also==