defines landrace and landrace breed as "a breed that has largely developed through adaptation to the natural environment and traditional production system in which it has been raised." This is in contrast to its definition of standardized breed: "a breed of livestock that was developed according to a strict programme of genetic isolation and formal artificial selection to achieve a particular phenotype." In various domestic species (including pigs, goats, sheep and geese) some standardized breeds include "Landrace" in their names, but do not meet widely used definitions of landraces. For example, the British Landrace pig is a standardized breed, derived from earlier breeds with "Landrace" names. Farmers' variety, usually applied to local cultivars, or seen as intermediate between a landrace and a cultivar, may also include landraces when referring to plant varieties not subjected to formal breeding programs. Autochthonous and allochthonous landraces A landrace native to, or produced for a long time within the agricultural system in which it is found is referred to as an autochthonous landrace, while a more recently introduced one is termed an allochthonous landrace. Within academic agronomy, the term autochthonous landrace is sometimes used with a more technical, productivity-related definition, synthesized by A. C. Zeven from previous definitions beginning with Mansholt's: "an autochthonous landrace is a variety with a high capacity to tolerate biotic and abiotic stress, resulting in a high yield stability and an intermediate yield level under a low input agricultural system." The terms autochthonous and allochthonous are most often applied to plants, with animals more often being referred to as indigenous or native. Examples of references in sources to long-term local landraces of livestock include constructions such as "indigenous landraces of sheep", and "Leicester Longwool sheep were bred to the native landraces of the region". Some usage of autochthonous does occur in reference to livestock, e.g. "autochthonous races of cattle such as the Asturian mountain cattle – Ratina and Casina – and Tudanca cattle." Biodiversity and conservation A significant proportion of farmers around the world grow landrace crops. However, as industrialized agriculture spreads, cultivars, which are selectively bred for high yield, rapid growth, disease and drought resistance, and other commercial production values, are supplanting landraces, putting more and more of them at risk of extinction. In 1927 at the International Agricultural Congress, organized by the predecessor of the FAO, an extensive discussion was held on the need to conserve landraces. A recommendation