History of plant breeding and a cultivated crop species that has evolved from wild populations due to selective pressures from traditional farmers is called a landrace. Landraces, which can be the result of natural forces or domestication, are plants or animals that are ideally suited to a particular region or environment. An example are the landraces of rice, "Oryza sativa" subspecies "indica", which was developed in South Asia, and "Oryza sativa" subspecies "japonica", which was developed in China. For more on the mechanisms of domestication, see Hybrid (biology). Humans have traded useful plants from distant lands for centuries, and plant hunters have been sent
Cannabis sativa Cannabis sativa Cannabis sativa is an annual herbaceous flowering plant indigenous to eastern Asia but now of cosmopolitan distribution due to widespread cultivation. It has been cultivated throughout recorded history, used as a source of industrial fiber, seed oil, food, recreation, religious and spiritual moods and medicine. Each part of the plant is harvested differently, depending on the purpose of its use. The species was first classified by Carl Linnaeus in 1753. The flowers of "Cannabis sativa" are unisexual and plants are most often either male or female. It is a short-day flowering plant, with staminate (male) plants usually taller