Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains which are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties, cultigens, or cultivars. The cross of animals results in what is called a crossbreed and crossbred plants are called hybrids. The term selective breeding is synonymous with artificial selection.
In animal breeding techniques such as inbreeding, linebreeding and outcrossing are utilized. In plant breeding similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his book, Origin of Species. The first chapter of the book discusses selective breeding and domestication of such animals as pigeons, dogs and cattle. Selective breeding was used by Darwin as a springboard to introduce the theory of natural selection, and to support it.

A Belgian Blue cow. The defect in the breeds myostatin gene is maintained through linebreeding and is responsible for its accelerated lean muscle growth