Canola oil (a variety of rapeseed oil), one of the most widely used cooking oils, from a (trademarked) cultivar of rapeseed.
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Canola is a type of edible oil. It is a trademarked quality description of a group of cultivars of rapeseed variants from which low erucic acid rapeseed oil and low glucosinolate meal are obtained. The word "canola" was derived from "Canadian oil, low acid" in 1978 . . The oil is also known as "LEAR" oil (for Low Erucic Acid Rapeseed)
Once considered a specialty crop in Canada, canola has evolved into a major North American cash crop. Canada and the United States produce between 7 and 10 million metric tons (tonnes) of canola seed per year. Annual Canadian exports total 3 to 4 million metric tons of the seed, 700,000 metric tons of canola oil and 1 million metric tons of canola meal. The United States is a net consumer of canola oil. The major customers of canola seed are Japan, Mexico, China and Pakistan, while the bulk of canola oil and meal goes to the United States, with smaller amounts shipped to Taiwan, Mexico, China, and Europe. World production of rapeseed oil in the 2002–2003 season was about 14 million metric tons. 
Canola was developed through conventional plant breeding from rapeseed, an oilseed plant with roots in ancient civilization. The word "rape" in rapeseed comes from the Latin word "rapum," meaning turnip. Turnip, rutabaga, cabbage, Brussels sprouts, mustard and many other vegetables are related to the two canola species commonly grown: Brassica napus and Brassica rapa. The negative associations with the word "rape" in North America resulted in the more marketing-friendly name "Canola". The change in name also serves to distinguish it from regular rapeseed oil, which has much higher erucic acid content.
Hundreds of years ago, Asians and Europeans used rapeseed oil in lamps. As time progressed, people employed it as a cooking oil and added it to foods. Its use was limited until the development of steam power, when machinists found rapeseed oil clung to water or steam-washed metal surfaces better than other lubricants. World War II saw high demand for the oil as a lubricant for the rapidly increasing number of steam engines in naval and merchant ships. When the war blocked European and Asian sources of rapeseed oil, a critical shortage developed and Canada began to expand its limited rapeseed production.
After the war, demand declined sharply and farmers began to look for other uses for the plant and its products. Edible rapeseed oil extracts were first put on the market in 1956–1957, but these suffered from several unacceptable characteristics. Rapeseed oil had a distinctive taste and a disagreeable greenish colour due to the presence of chlorophyll. It also contained a high concentration of erucic acid. Experiments on animals have pointed to the possibility that erucic acid, consumed in large quantities, may cause heart damage, though Indian researchers have published findings that call into question these conclusions and the implication that the consumption of mustard or rapeseed oil is dangerous.      Feed meal from the rapeseed plant was not particularly appealing to livestock, due to high levels of sharp-tasting compounds called glucosinolates.
Plant breeders in Canada, where rapeseed had been grown (mainly in Saskatchewan) since 1936, worked to improve the quality of the plant. In 1968 Dr Baldur Stefansson of the University of Manitoba used selective breeding to develop a variety of rapeseed low in erucic acid. In 1974 another variety was produced low in both erucic acid and glucosinolates; it was nameed Canola, from Canadian Oil Low Acid.
A variety developed in 1998 is considered to be the most disease- and drought-resistant variety of Canola to date. This and other recent varieties have been produced by gene splicing techniques.
An Oregon State University researcher has determined that growing winter canola for hybrid seed appears possible in central Oregon, USA. Canola is the highest-producing oil-seed crop, but the state prohibits it from being grown in Deschutes, Jefferson and Crook counties because it may attract bees away from specialty seed crops such as carrots which require bees for pollination.