The Canola Story

Canola becomes a crop

Authored by Dr. Keith Downey

The story of canola began in 1942, the middle of World War II. At that time, all trains and ships were steam powered and to keep them running smoothly, oil from the rapeseed species Brassica napus and B. rapa were essential. This was because rapeseed oil clings to metal surfaces, when washed with steam or water, better than any other lubricant. When the war cut off supplies from Asia and Europe, Canada was asked if it could grow the crop. Experimental plantings confirmed that with minor adjustments to seeding and harvest equipment, the crop was admirably adapted to the cooler, moister regions of the Canadian prairies. Seed of the B. napus species was quickly increased from a sample of seed thought to have originated in Argentina while a Shellbrook farmer distributed B. rapa seed he had brought with him from Poland in 1936. Thus, the two species became known in Canada as Argentine and Polish types.

Commercial production began in 1943 with a government guaranteed price of 6c/lb and production quickly expanded to 79,000 acres by 1948, about 75% of which was B. rapa. However, with the war over and diesel replaced steam power, the government withdrew its support price and the market and crop almost disappeared. Fortunately, an edible oil market was found in Japan where rapeseed oil was the traditional deep-frying oil (Tempura), and the crop was saved.

From the outset scientists involved recognized that rapeseed could also be an edible oil source for Canada. At that time Canada imported 90% of its edible oil needs and some companies in the early 50s began to market the oil domestically. This new product in the edible market interested Canadian nutritionists who reported that lab animals fed rapeseed oil performed poorly under stress and had enlarged adrenal glands. Further lab animal studies reported additional nutritional problems suggesting that the fatty acid composition of rapeseed oil was the cause. Fatty acids are the building blocks of an oil and the fatty acid composition of an oil determines its utility, value and nutritional quality. For example, linolenic and linoleic acids are essential fatty acids for human nutrition. Rapeseed oil differs from other edible oils in containing a substantial amount of long carbon chain, monoenoic fatty acids, eicosenoic and erucic acid. Their nutritional value was questioned.

These nutritional concerns focused scientists on discovering efficient techniques to search for rapeseed germplasm with little or no long chain fatty acids. Scientists at the National Research Laboratory in Saskatoon introduced and built a new instrument called a gas chromatograph that could analyze an oil’s composition in minutes, compared with the previous technique requiring a 2-pound sample of seed and a week’s time. Thanks to this breakthrough plant breeders produced the first low erucic varieties of B. napus in 1968 and in B. rapa in 1971 (Oro and Span, respectively). The elimination of the long chain fatty acids was achieved by genetically blocking the biosynthetic pathway for erucic as the oil is laid down in the developing seed. Tests of this new natural oil showed it to be nutritionally desirable and ideally suited as a salad and cooking oil as well as in margarine shortening blends. Further reports of the anti-nutritional effect of high erucic rapeseed oil were presented at the Second International Rapeseed Congress in 1970. To protect the crop, Canada decided to take what little seed we had of the low erucic strains of both species to California that winter to replace the old high erucic varieties with Oro and Span. The returning seed was sown in 1971 and with the cooperation of the entire industry, conversion to low erucic varieties, was completed by 1973.

Other producing countries followed Canada’s lead in converting their production. However, the export of rapeseed oil or seed into the United States was blocked because rapeseed oil was not used in the U.S. before 1958. Thus, it was not included in their list of ingredients considered Generally Recognized As Safe (GRAS). Agriculture Canada undertook a very large body of nutritional research to obtain canola GRAS status in 1985, thus opening the US market to Canadian canola oil. 

Research into the fatty acid composition of rapeseed oil established that each step along the fatty acid biosynthetic pathway was controlled by an enzyme that could be genetically manipulated. As a result, specialty oil varieties have been developed and grown under contract. These include the extremely high erucic (>50) varieties for the plastics industry and the low linolenic, high oleic varieties with extended keeping qualities and absence of cooking odors. Recently a canola oil nutritional supplement, containing very long chain fatty acids, promises to reduce inflammation and support brain and eye health. 

Although a superior nutritional and functional oil had been produced a major market constraint remained, namely, the utilization of the high protein meal remaining after oil extraction. Even though the protein quality of the meal was equal to soya meal, feed efficiency and weight gains were well below expected levels when rapeseed meal was fed to swine and poultry. This restricted feed market in turn limited the amount of seed that could be processed. The problem was the presence of sulfur compounds in the seed called glucosinolates. Although these compounds give the desirable flavor and odor to vegetables like cabbage, turnip, mustard and many other cruciferous crops, the rapeseed plant concentrates glucosinolates at high levels in the seed. When the seed is crushed and moisture is present the glucosinolates release isothiocynates that interfere with the iodine uptake by the thyroid gland in nonruminant animals.

To breed rapeseed plants free of glucosinolates, again new chemical methodologies had to be developed to rapidly and accurately measure the various glucosinolates within a small sample of seeds. Using these new techniques, breeders where able to identify a strain of B. napus with a reduced glucosinolate content and from that germplasm, they were able to produce the first low erucic, low glucosinolate variety, Tower in 1974 and the first double low B. rapa variety, Candle, in 1977.

By 1980, with the cooperation of everyone in the industry, the 6-million-acre commercial crop was converted to the new double low varieties thus removing the meal market constraint. Animal nutritionists at several universities conducted extensive studies to convince both domestic and foreign feed formulators that low glucosinolates meal was indeed a safe, wholesome and an economic feed. Indeed, it is now established that dairy cows fed canola meal produce over 1 liter more milk per day than when fed other commonly used protein supplements (such as soya meal).

As a result of the nutritional upgrading of the oil and meal, a new name for the crop and its products was required and the name, “canola” was coined, defined and trademarked. The development of canola is considered a success story because it diversified Canada’s agriculture base, eliminated Canada’s dependence on edible oil imports, and increased returns to producers while expanding markets at home and abroad. In addition, it also resulted in the established a large rural based, value added, oilseed crushing and refining industry. Canola has also responded to all the biotechnologies with nearly all the crop herbicide tolerant and hybrid varieties dominating the acreage.

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