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Rapeseed (Brassica napus), also known as rape, oilseed rape, rapa, rapaseed and (in the case of one particular group of cultivars) canola, is a bright yellow flowering member of the family Brassicaceae (mustard or cabbage family). The name is derived from the Latin for turnip, rāpum or rāpa, and is first recorded in English at the end of the 14th century. Older writers usually distinguished the turnip and rape by the adjectives round and long(-rooted) respectively. See also Brassica napobrassica, which may be considered a variety of Brassica napus. Some botanists include the closely related Brassica campestris within B. napus. (See Triangle of U)
Cultivation and uses
Rapeseed is grown for the production of animal feed, vegetable oil for human consumption, and biodiesel; leading producers include the European Union, Canada, the United States, Australia, China and India. In India, it is grown on 13% of cropped land. According to the United States Department of Agriculture, rapeseed was the third leading source of vegetable oil in the world in 2000, after soybean and oil palm, and also the world's second leading source of protein meal, although only one-fifth of the production of the leading soybean meal. World production is growing rapidly, with FAO reporting that 36 million tonnes of rapeseed was produced in the 2003-4 season, and 46 million tonnes in 2004-5. In Europe, rapeseed is primarily cultivated for animal feed (due to its very high lipid and medium protein content), and is a leading option for Europeans to avoid importation of GMO products. Natural rapeseed oil contains erucic acid, which is mildly toxic to humans in large doses but is used as a food additive in smaller doses. Canola, originally a syncopated form of the abbreviation "Can.O., L-A." (Canadian Oilseed, Low-Acid) that was used by the Manitoba government to label the seed during its experimental stages, is now a tradename for low erucic acid rapeseed that is sometimes mis-applied to other varieties.
The rapeseed is the valuable, harvested component of the crop. The crop is also grown as a winter-cover crop. It provides good coverage of the soil in winter, and limits nitrogen run-off. The plant is ploughed back in the soil or used as bedding. On some ecological or organic operations, livestock such as sheep or cattle are allowed to graze on the plants.
Processing of rapeseed for oil production provides rapeseed animal meal as a by-product. The by-product is a high-protein animal feed, competitive with soya. The feed is mostly employed for cattle feeding, but also for pigs and chickens (though less valuable for these). The meal has a very low content of the glucosinolates responsible for metabolism disruption in cattle and pigs. Rapeseed "oil cake" is also used as a fertilizer in China, and may be used for ornamentals, such as Bonsai, as well.
Rapeseed leaves and stems are also edible, similar to those of the related bok choy or kale. Some varieties of rapeseed (called 油菜, yóu cài, lit. "oil vegetable" in Chinese; yau choy in Cantonese; cải dầu in Vietnamese; and 菜の花, nanohana in Japanese) are sold as greens, primarily in Asian groceries.
Rapeseed is a heavy nectar producer, and honeybees produce a light colored, but peppery honey from it. It must be extracted immediately after processing is finished, as it will quickly granulate in the honeycomb and will be impossible to extract. The honey is usually blended with milder honeys, if used for table use, or sold as bakery grade. Rapeseed growers contract with beekeepers for the pollination of the crop.
Canola oil (or rapeseed oil) contains both omega-6 and omega-3 fatty acids in a ratio of 2:1 and is second only to flax oil in omega-3 fatty acid. It is one of the most heart-healthy oils and has been reported to reduce cholesterol levels, lower serum tryglyceride levels, and keep platelets from sticking together. Some UK farmers (such as Hillfarm Oils) & Farrington Oils) have started to produce cold-pressed rapeseed oil as a versatile cooking oil and dressing, similar in use to olive oil.
Rapeseed oil is used in the manufacture of biodiesel for powering motor vehicles. Biodiesel may be used in pure form in newer engines without engine damage, and is frequently combined with standard diesel in ratios varying from 2% to 20% biodiesel. Formerly, due to the costs of growing, crushing, and refining rapeseed biodiesel, rapeseed derived biodiesel cost more to produce than standard diesel fuel. Prices of rapeseed oil are at very high levels presently (start November 05) due to increased demand on rapeseed oil for this purpose. Rapeseed oil is the preferred oil stock for biodiesel production in most of Europe, partly because rapeseed produces more oil per unit of land area as compared to other oil sources, such as soy beans.
Rapeseed and health
Rapeseed has been linked with adverse effects in asthma and hay fever sufferers. Some suggest that oilseed pollen is the cause of increased breathing difficulties. This is unlikely however, as rapeseed is an entomophilous crop, with pollen transfer primarily by insects. Others suggest that it is the inhalation of oilseed rape dust that causes this, and that allergies to the pollen are relatively rare. There may also be another effect at work; since rapeseed in flower has a distinctive and pungent smell, hay fever sufferers may wrongly jump to the conclusion that it is the rapeseed that is to blame simply because they can smell it. An alternative explanation may be that it is simply the sheer volume of rapeseed pollen in the air around farmland which triggers an allergic reaction in hayfever sufferers on inhalation, or following prolonged exposure to high levels.
The Monsanto Company has genetically engineered new cultivars of rapeseed that are resistant to the effects of its herbicide Roundup. They have been vigorously prosecuting farmers found to have the Roundup Ready gene in Canola in their fields without paying a license fee. These farmers have claimed the Roundup Ready gene was blown into their fields and crossed with unaltered Canola. Other farmers claim that after spraying Roundup in non-Canola fields to kill weeds before planting, Roundup Ready volunteers are left behind, causing extra expense to rid their fields of the weeds.
In a closely followed legal battle, the Supreme Court of Canada found in favor of Monsanto's patent infringement claim for illegal growing of Roundup Ready in its 2004 ruling on Monsanto Canada Inc. v. Schmeiser. The case garnered international controversy as a court-sanctioned legitimation for the global patent protection of genetically modified crops.
Worldwide production of rapeseed (including canola) rose to 46.4 million metric tons in 2005, the highest recorded total (source: FAO).
Pests and diseases affecting rapeseed
White rust diease (Albugo candida)
Genome sequencing and genetics
The 'A' genome component of the amphidiploid Rapeseed species B. napus is currently being sequenced by an international consortium. 
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Rapeseed". A list of authors is available in Wikipedia.|