Oilseed Crops are grown primarily for the oil contained in the seeds. The oil content of small grains (eg, wheat) is only 1-2%; that of oilseeds ranges from about 20% for soybeans to over 40% for sunflowers and rapeseed (canola). The major world sources of edible seed oils are soybeans, sunflowers, rapeseed, cotton and peanuts. Seed oils from flax (linseed) and castor beans are used for industrial purposes. Edible fats and oils are similar in molecular structure; however, fats are solid at room temperature, while oils are liquid.

The major oilseeds grown in Canada are soybeans, sunflowers, canola and flax. In addition, experimental production of peanuts on a commercial scale began in 1981 in southwestern Ontario. Plant breeding experiments are underway at the Agriculture Canada Research station, Saskatoon, Saskatchewan, to develop an edible oil from mustard seed and a usable animal feed from the residue. The program involves reducing the content of 2 harmful substances, erucic acid and glucosinolate, which were formerly a problem in rapeseed oil.