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Brassica napus L.

Rape, Colza

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Toxicity
  5. Description
  6. Germplasm
  7. Distribution
  8. Ecology
  9. Cultivation
  10. Harvesting
  11. Yields and Economics
  12. Energy
  13. Biotic Factors
  14. References


Grown sparingly for young leaves used as potherb; more generally grown as forage for livestock feed, and as source of rapeseed oil. Rape oil used in food industry, as an illuminant and lubricant, and for soap manufacture. Residual rapeseed cake, though low in food value, used as livestock feed. Rapeseed oil has potential market in detergent lubrication oils, emulsifying agents, polyamide fibers, and resins, and as a vegetable wax substitute. According to the Chemical Marketing Reporter (April 26, 1982) "the most common use for the oil is still in the production or erucic acid, a fatty acid used in turn in the manufacture of other chemicals. Sprouts are used dietetically and as seasoning.

Folk Medicine

The seed, powdered, with salt is said to be a folk remedy for cancer. Rape oil is used in massage and oil baths, believed to strengthen the skin and keep it cool and healthy. With camphor it is applied for rheumatism and stiff joints. Medicinally, root used in chronic coughs and bronchial catarrh.


Per 100 g, the inflorescence is reported to contain 37 calories, 87.4 g H2O, 4.3 g protein, 0.4 g fat, 6.4 g total carbohydrate, 1.5 g ash, 117 mg Ca, 97 mg P, 3.4 mg Fe, 3200 mg b-carotene equivalent, 0.04 mg thiamine, 0.02 mg riboflavin, 1.2 mg niacin, and 42 mg ascorbic acid. Per 100 g, the leaf is reported to contain 61 calories, 83.3 g H2O, 2.9 g protein, 1.7 g fat, 11.2 g total carbohydrate, 1.8 g fiber, 0.9 g ash, 136 mg Ca, 38 mg P, 4.6 mg Fe, 2680 mg b-carotene equivalent, 0.08 mg thiamine, 0.15 mg riboflavin, 0.5 mg niacin, and 120 mg ascorbic acid. Per 100 g, the root is reported to contain 46 calories, 87.0 g H2O, 1.1 g protein, 0.1 g fat, 11.0 g total carbohydrate, 1.1 g fiber, 0.8 g ash, 66 mg Ca, 39 mg P, 0.4 mg Fe, 5 mg Na, 239 mg K, 348 mg b-carotene equivalent, 0.07 mg thiamine, 0.07 mg riboflavin, 1.1 mg niacin, and 43 mg ascorbic acid. Rape cake contains a sinigrin-like substance called gluconapin, which on hydrolysis yields an irritant sulphur containing oil. Seed contains six glucosides; glucobrassicanapin, glucoiberin, gluconapin, gluconasturtin, glucorapiferin (progoitrin) and sinalbin. Glycerides from the leaves yield hexadecatrienoic acid. Root contains allantoic acid and allantoin. Contains the glucosinolate sinigrin (potassium myronate) and the enzyme myrosin (myrosinase); sinapic acid; sinapine (sinapic acid choline ester); fixed oils (25 to 37%) consisting mainly of glycerides of erucic, eicosenoic, arachidic, nonadecanoic, behenic, oleic, and palmitic acids, among others; proteins (e.g., globulins); and mucilage (Leung, 1980). Sinigrin on hydrolysis by myrosin (myrosinase) yields allyl isothiocyanate, glucose, and potassium bisulfate. Allyl isothiocyanate is volatile; other minor volatile components set free by enzymatic hydrolysis include methyl, isopropyl, sec-butyl, butyl, 3-butenyl, 4-pentenyl, phenyl, 3-methylthiopropyl, benzyl, and b-phenylethyl isothiocyanates.


Irritant poisoning of stock can occur with acute or hemorrhagic gastroenteritis. Rape seed, containing the goitrogenic L-5-vinyl-2-thiooxazolidone, can produce goiter in animals consuming modest quantities. Rape has been incriminated in several poisoning syndromes, i.e. respiratory, digestive, nervous, and urinary.


Annual or biennial, when sown late and flowering the following spring, with slender or stout, hard, long, fusiform tuberous taproot; stems erect, much-branched, up to 1.5 m tall, often purple toward base; leaves glaucous, the lower ones lyrate-pinnatifid or lobed, with petioles 10–30 cm long, glabrous or with a few bristly hairs, upper stem leaves lanceolate, sessile, clasping, more or less entire; flowers pale yellow, 1.2–1.5 cm long, open flowers not overtopping buds of inflorescence; inflorescence much-branched, up to 1 m tall as an elongating raceme; silique 5–11 cm long, 2.5–4 mm wide, with slender beak 0.5–3 mm long. Underground part curved or crooked for 5–7.5 cm and then dividing into stout horizontal branches. Fl. late spring to fall; fr. early summer to fall.


It is thought that crosses of Brassica oleracea subsp. oleracea (2n = 18) with B. rapa (2n = 20) gave rise to subsp. pabularia (2n = 38), from which subsp. napus (2n = 38) and subsp. rapifera (2n = 38) and other cvs were derived. Brassica napus subsp. napus—'Target type' has dark green leaves, mostly self-pollinated, height 1.3–2 m tall, seed very dark brown to black when mature, 130,000 seeds/lb., maturing in December in Western Australia, requiring 192–204 days to maturity. Brassica napus subsp. pabularia (DC.) Janchen (Syn.: B. napus var. pabularia (DC.) Reichenb.)—Hanover kale, Leaf-rape, Siberian kale, has a slender annual root and crispate, dissected leaves. Brassica napus subsp. oleifera DC.—Oilseed rape, Summer rape is a biennial with non-tuberous root and lyrate-pinnatifid leaves. Main variety grown in Canada and Western Australia, including 'Target', 'Turret', 'Oro', and 'Zaphyr', the last two being free of erucic acid. Leading rape cvs for oilseeds in Minnesota are: 'Golden', 'Nugget', and 'Tankal which originated in Canada. Winter rape cvs are: 'Tenus', 'Matador', and 'Dwarf Essex'. Rapeseed oil is the principal commercial source of erucic acid; however, there is no urgency to develop cvs with higher erucic acid content since its production is controlled by a single gene. Among annual cvs, 'Argentine Black' is the best type to grow in western Canada, as it requires the same time as wheat to mature, grows to 66–105 cm tall, with a coarse profusely branched main stem, but the fruit tends to split open and shatter the seed. 'Golden' a selection of Argentine type, yields 3–4% more oil and is more resistant to 'lodging'. Polish rape is 3 weeks earlier maturing than Argentine types, yielding 60–70% as much oil. Reported from the Mediterranean and Eurosiberian Centers of Diversity, rape or cvs thereof, is reported to tolerate bacteria, frost, high pH, laterite, low pH, and virus. (2n = 38)


Known only as a cultigen, sometimes escaped. Throughout temperate regions. Cultivated in most European countries, but naturalized in most.


Requires fertile, well-drained soils. Responds favorably to nitrogen and phosphate fertilizers, but can be injured by contact with the fertilizer. Use only low rates of fertilizers in drills where both seed and fertilizer empty into same tubes. Sunny days and cool nights are favorable for growth; dry weather at harvest time is essential. Ranging from Boreal Moist to Rain through Tropical Dry to Moist Forest Life Zones, rape is reported to tolerate annual precipitation of 3 to 28 dm (mean of 90 cases = 8.3), annual temperature of 5 to 27°C (mean of 90 cases = 11.6), and pH of 4.2 to 8.2 (mean of 86 cases = 6.2) (Duke, 1978, 1979).


Fall plowing and preparation of a good firm seedbed is desirable as rape seeds are small. Cultipacking before seeding make a firm even seedbed. Germination must be fast with uniform emergence for the crop to get ahead of the weeds. Seed of Polish and Argentine types germinate readily when moisture and temperature conditions are suitable. Seed rate and spacing of rows varies in different areas. Sow seed with a grain drill, in rows 30–40 cm apart. Because seed are so small, it is recommended to mix 50–50 with cracked grain, so as to spread out the rape seed; for a 10 kg/ha rate, calibrate the drill for 20 kg/ha of mixture. If fertilizer is used mixed with the seed when sowing, sow about 30 kg/ha of mixture and mix at the time of sowing. Seed may be sown with a grass-seed attachment, or broadcast and then harrowed or disced lightly. Depth of sowing should be 2.5 cm or less, but seedlings will emerge from 5 cm or more if soil does not crust on top. Seedlings develop slowly and are easily destroyed by drifting soil. Spreading manure where drifting might start helps trap drifting soil. Early sowings give higher yields, but crop is more susceptible when emerging, -4°C either killing or injuring seedlings, whereas -2°C has no affect when one month old. Sowing in late April or early May is best in northern areas; sowing as late as June or early July give rather good results. Rape may be planted after grains, flax, corn, potatoes, sugar beets or fallow, but not after rape, mustards or sunflowers (Reed, 1976).


Because fruit ripens evenly and shatter easily, to avoid shattering, it is recommended to harvest crop when yellow and windrow to ripen until seed inside is ust changing from yellow to brown. Dry, mature seed may be harvested directly with combine. To combine standing crop, it is best to leave the crop until seeds are fully ripe, and with reel speed reduced to two-thirds normal speed for cereals, harvest crop during cloudy weather when plants are moist, thus reducing shattering. In some areas crop is cut by hand and then flailed with sticks after drying in sun for a few days. In humid and temperate regions, artificial drying may be necessary (Reed, 1976).

Yields and Economics

Seed yields vary from 900 to 3,000 kg/ha; in North Africa it may be only 300–350 kg/ha. Rapeseed contain an average of 40% oil on a dry matter basis. Rapeseed is capturing an increasing share of world edible oilseed market, competing with soybeans, peanuts, safflower, and sunflower seed; in 1970 it was about 5% of the market, and expected to increase about 4.7% by 1980. Rapeseed oil production in 1970 was 1.7 million tons, priced at $293/MT. Rape is the most important oil seed crop in Western Europe, and Canada is encouraging more production. Almost all Canada's oil is exported. World production of rapeseed oil is about 5 million tons. In April 1972, rapeseed oil was trading at $1.23 per kg (CMR, April 26, 1982).


In Europe, ca 1 million MT rape and colza seed are produced per year. One estimate puts the straw associated with such a seed yield at 1.2 million MT (DM). However, another estimate would put the straw yield at 5.8 million MT suggesting a grain:straw ratio of only 0.17 (Palz and Chartier, 1980). The oil content runs 35–45%, and oil yields of more than 1 MT/ha are reported. In Canada, Finlayson et al. (1973) report yields of only 718 kg/ha in the low-glucosinolate cv 'Bronowskil compared to 1,304 for 'Target'. Yield data for their 1972 trials at Saskatoon were ca 2,960 kg/ha (41.7% oil) for 'Target' ca 2,560 (39.6%) for 'Zephyr', ca 3,010 (44.2%) for 'Midas', ca 2,630 (42.4%) for ISZN71-1788', ca 2,500 (41.7%) for 'SZN71-1787' ca 2,720 (42.3%) for 'SZN71-1785', ca 2,550 kg/ha (41.1% oil) for 'SZN71-1784', nearly all yielding more than a metric ton oil per hectare (Finlayson et al., 1973). In three experiments comparing autumn- and spring-sown rape in Britain, seed yields for the spring sown ranged from 963–2,284 kg/ha, for autumn-sown, from 1,787–2,783 kg/ha. Not only did the autumn-sown crop have higher yields, it had a higher oil content (42.0–44.5%) than the spring sown (35.8–38.5%) (Scott et al., 1973). Scott et al. (1973), indicate aerial DM yields of 1–2 MT with seed yields of about the same magnitude suggesting a straw factor of 1. Rape oil can be used as fuel in diesel engines. A mixture of castor oil and rape oil, with 1% a-napththlyamine can be used as a lubricant in internal combustion engines. Vegetable oil (safflower, mustard, rape) is better than alcohol as a diesel extender, with mixtures up to 75% vegetable oil possible compared with 20% alcohol. Vegetable oils provide >2x the gross energy and 10x more net energy. Rape yields of 1500 kg/ha would yield 500 kg oil and 1000 kg high protein meal. One tenth of a farm's acreage can produce energy for the other 9/10 according to some optimistic estimates. The world low production yield was 400 kg/ha in Ethiopia, the international production yield was 856 kg/ha, and the world high production yield was 3,000 kg/ha in Belgium and Luxemburg (FAO, 1980a). The oil content runs 35–45%, and oil yields of more than 1 MT/ha are reported.

Biotic Factors

Rape is 70% self-pollinating and 30% cross-pollinated. Even if wind and insects are absent, seed are still produced. Yield increases with honeybees. Competes with alfalfa and clover for insect pollination. Rape honey has slightly less flavor and granulates more easily than clover honey. Following fungi are known to cause diseases in rape: Albugo candida, A. macrospora, Alternaria brassicicola, A. brassicae, A. oleracea, A. tenuis, Botrytis cinerea, Cercospora brassicicola, C. armoraciae, Cercosporella brassicae, Cylindrosporium brassicae, Cytopus candidus, Erysiphe communes, E. polygoni, Leptosphaerella napi, Mycosphaerella brassicicola, Ophiolobus graminis, Pernonospora parasitica, P. brassicae, Plasmodiophora brassicae, Phoma lingam, P. napobrassicae, P. oleracea, Phyllosticta brassicae, Pythium debaryanum, P. perniciosum, Rhizopus oryzae, Rhizoctonia solani, Sclerotinia libertiana, S. fuckeliana, S. sclerotiorum, Stemphylium consortiale, Tuberculariella brassicae. Viruses causing diseases of rape include: Argentine sunflower, Cabbage black-ring, Cauliflower mosaic, Cucumber mosaic, Trinidad cucumber mosaic, Turnip crinkle, Tobacco mosaic, Yellow spot of Nasturtium. Bacterial diseases are caused by Pseudomonas destructans, P. maculicola and Xanthomonas campestris. Insects are major pests of rape; sprayings should be planned and official recommendations followed. Fleabeetles, cutworms, red turnip beetles attack seedlings, and these, along with Diamondback moth, Beet webworm, Bertha armyworm and Imported cabbage worm, attack from bud stage until maturity. Red-legged earth mite (Halotydeus destructor), in western Australia, Cutworms (Agrotis spp.); Cabbage moth (Plutella xylostella); Rutherglen bug (Nysius vinitor); aphids; weevils (Listroderes costirostris); Cabbage white butterfly (Artogeia rapae); Australian budworm (Heliothis punctigera). Nematodes include Ditylenchus dipsaci, Helicotylenchus pseudorobustus, Heterodera crucifera, H. schactii, Meloidogyne artiellia, M. hapla, M. javanica, M. sp., Nacobbus aberans, Pratylenchus neglectus, and P. penetrans (Golden, p.c., 1984)


Complete list of references for Duke, Handbook of Energy Crops
Last update Tuesday, December 30, 1997