Brief SummaryRead full entry
1) rape, rapeseed, oilseed rape, or the Canadian variety canola (from the varieties napus and oleifera), used for the oil obtained from the seeds;
2) Siberian or rape kale (from the variety pabularia); used for the leaves, which are used as a cooked vegetable or for salads—although other Brassica species and varieties, including B. oleacea var. acephala also produce leafy greens known as kale; and
3) rutabagas or swedes (from the variety napobrassica), for the creamy white or yellow fleshy, turnip-like roots, which are used as a cooked vegetable, similar to turnips.
Brassica species including B. napus have such a long history of cultivation and diversification that their centers of origin are not known, and the classification of varieties and species is under constant debate and revision. B. napus was likely native to Eurasia, and is most commonly grown in northern temperate regions. It is thought to have originated as a garden hybrid between cabbage (B. olearacea var. capitata) and turnips (B. rapa var. rapa), and has been cultivated since the Middle Ages.
The diverse varieties of B. napus have different growth forms, but in general, they have glaucous (waxy) leaves that occur in a rosette, if the variety is biennial or planted late to overwinter. The leaves are pinnatifid (deeply lobed) or lyrate (deeply lobed, but with an enlarged terminal lobe and smaller lateral lobes), and are often somewhat bristly. The yellow, four-parted and cross-shaped flowers, produce a silique—a two-parted capsular fruit that dehisces (splits open) when mature—that may be up to 11 cm (4.5 in) long, each containing several hard round seeds that contain up to 40% oil.
Rapeseed oil is used for cooking and as a salad oil, as well as in mayonnaise and margarine. Siberian kale is cooked as a leafy green vegetable, or marinated and used for salads. Rutabagas, which are high in vitamin C and minerals, are hardier and easier to grow than turnips, but cooked and used in similar ways.
Statistics on the production and harvest of kale and rutabagas are lumped together with cabbages and other Brassica species, so it is hard to estimate aggregate production for all varieties this species. However, rapeseed, which has become a leading source of edible oil and is also used for biodiesel, likely accounts for the largest share of production. In 2010, the FAO estimates that total commercial production of rapeseed worldwide was 59.1 million metric tons, harvested from 31.7 million hectares. China and Canada were the leading producers of rapeseed (including canola), along with India, Germany, and France. The U.S. ranked 10th for total commercial production.
(Bailey et al. 1976, FAOSTAT 2012, van Wyk 2005.)