A landrace is a domesticated, locally adapted,[1][2][3] traditional variety[4] of a species of animal or plant that has developed over time, through adaptation to its natural and cultural environment of agriculture and pastoralism, and due to isolation from other populations of the species.[1] Landraces are generally distinguished from cultivars, and from breeds in the standardized sense, although the term landrace breed is sometimes used[by whom?] as distinguished from the term standardized breed[further explanation needed] when referring to cattle.[5]

Specimens of a landrace tend to be genetically very similar, though more diverse than members of a standardized or formal breed.[1] Some standardized animal breeds originate from attempts to make landraces more consistent through selective breeding, and a landrace may become a more formal breed with the creation of a breed registry and/or publication of a breed standard. In such a case, one may think of the landrace as a "stage" in breed development. However, in other cases, formalizing a landrace may result in the genetic resource of a landrace being lost through crossbreeding.[1] Landraces are distinct from ancestral wild species of modern stock, and from separate species or subspecies derived from the same ancestor as modern domestic stock. Not all landraces derive from ancient stock largely unmodified by human breeding interests. In a number of cases, most commonly dogs and horses, domestic animals have escaped in sufficient numbers in an area to breed feral populations that, through evolutionary pressure, can form new landraces in only a few centuries. In other cases, simple failure to maintain breeding regimens can do the same.[citation needed] For example, selectively bred cultivars can become new landraces when loosely selective reproduction is applied.[6]

Increasing adoption of and reliance upon modern, purposefully selected plant strains, considered improved – "scientifically bred to be uniform and stable"[7] – has led to a reduction in biodiversity.[7][8] The majority of the genetic diversity of domesticated species lies in landraces and other traditionally used varieties,[8] a "reservoir of genetic resources".[7]

Landrace chicken varieties include:

Landrace duck varieties include:

Landrace goose varieties include: