Old English bredan "bring young to birth, carry," also "cherish, keep warm," from West Germanic *brodjan (cf. Old High German bruoten, German brüten "to brood, hatch"), from *brod- "fetus, hatchling," from PIE *bhreue- "burn, heat" (see brood (n.)). Original notion of the word was incubation, warming to hatch. Sense of "grow up, be reared" (in a clan, etc.) is late 14c. Related: Bred; breeding.
"race, lineage, stock" (originally of animals), 1550s, from breed (v.). Of persons, from 1590s. Meaning "kind, species" is from 1580s.
application of genetic principles to produce plants that are more useful to humans. This is accomplished by selecting plants found to be economically or aesthetically desirable, first by controlling the mating of selected individuals, and then by selecting certain individuals among the progeny. Such processes, repeated over many generations, can change the hereditary makeup and value of a plant population far beyond the natural limits of previously existing populations. This article emphasizes the application of genetic principles to the improvement of plants; the biological factors underlying plant breeding are dealt with in the article heredity.