Brassica rapa is an annual to biennial plant species native to Eurasia that is from the Brassicaceae family. The B. rapa subspecies oleifera is an oilseed commonly known as turnip rape, field mustard, bird's rape, and keblock.
It has been widely cultivated into many forms, including the turnip (a root vegetable), komatsuna, Chinese cabbage, bomdong, pak choi / bok choy, and rapini. Its domesticated forms include turnips and leafy greens, such as bok choy and napa cabbage. The oilseed types are grown for food and industrial uses. Genetic studies indicate that B. rapa was one of the earliest domesticated brassicas, with turnip-like forms arising first and additional morphotypes developing independently across Eurasia. Wild, feral, and cultivated populations are found worldwide, making the species important agriculturally, economically, and ecologically.
Rapeseed oil is a general term for oil from some Brassica species. Food grade oil made from the seed of low-erucic acid Canadian-developed strains is also called canola oil, while non-food oil is called colza oil. Canola oil can be sourced from Brassica rapa and Brassica napus, which are commonly grown in Canada, and Brassica juncea, which is less common.
History
Illustration of Brassica rapa from the Japanese agricultural encyclopedia Seikei Zusetsu.
The geographic and genetic origins of B. rapa have been difficult to identify due to its long history of human cultivation, as well as difficulty finding Brassica seeds at archaeological sites. It is found in most parts of the world, and has returned to the wild many times as a feral plant or weed. Recent genomic studies show that many “wild” populations found in Europe and the Americas are actually feral descendants of cultivated plants, while actual wild populations appear to be from regions such as the Caucasus and Central Asia.
Genetic sequencing and environmental modeling have indicated that ancestral B. rapa likely originated 4000 to 6000 years ago in the...
