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Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains appreciable amounts of erucic acid. The term '' canola'' denotes a group of rapeseed
cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...
s which were bred to have very low levels of erucic acid and are especially prized for use as human and animal food. Rapeseed is the third-largest source of vegetable oil and the second-largest source of protein meal in the world.


Description

''Brassica napus'' grows to in height with hairless, fleshy, pinnatifid and glaucous lower leaves which are stalked whereas the upper leaves have no petioles. ''Brassica napus'' can be distinguished from ''
Brassica nigra ''Brassica nigra'', or black mustard, is an annual plant cultivated for its dark-brown-to-black seeds, which are commonly used as a spice. It is native to tropical regions of North Africa, temperate regions of Europe, and parts of Asia. Desc ...
'' by the upper leaves which do not clasp the stem, and from '' Brassica rapa'' by its smaller petals which are less than across. Rapeseed flowers are bright yellow and about across. They are radial and consist of four petals in a typical cross-form, alternating with four sepals. They have indeterminate racemose flowering starting at the lowest bud and growing upward in the following days. The flowers have two lateral stamens with short filaments, and four median stamens with longer filaments whose anthers split away from the flower's center upon flowering. The rapeseed pods are green and elongated siliquae during development that eventually ripen to brown. They grow on
pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as ''pedicellate''. Description Pedicel refers to a structure connecting a single flower to its inflorescence. In the absenc ...
long, and can range from in length. Each pod has two compartments separated by an inner central wall within which a row of seeds develops. The seeds are round and have a diameter of . They have a reticulate surface texture, and are black and hard at maturity.


Etymology and taxonomy

The term "rape" derives from the Latin word for turnip, ''rapa'' or ''rapum'', cognate with the Greek word ''rhapys''. The
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
''Brassica napus'' belongs to the flowering plant family Brassicaceae. Rapeseed is a subspecies with the autonym ''B. napus ''subsp.'' napus''. It encompasses winter and spring oilseed, vegetable and fodder rape. Siberian kale is a distinct leaf rape form variety (''B. napus ''var.'' pabularia'') which used to be common as a winter-annual vegetable. The second subspecies of ''B. napus'' is ''B. napus ''subsp.'' rapifera'' (also subsp. ''napobrassica''; the rutabaga, swede, or yellow turnip). ''Brassica napus'' is a digenomic amphidiploid that occurred due to the interspecific hybridization between ''
Brassica oleracea ''Brassica oleracea'' is a plant species from family Brassicaceae that includes many common cultivars used as vegetables, such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy cabbage, kohlrabi, and gai lan. It ...
'' and '' Brassica rapa''. It is a self-compatible pollinating species like the other amphidiploid ''brassica'' species.


Ecology

In Northern Ireland, U K ''B. napus'' and ''B. rapa'' are recorded as escapes in roadside verges and waste ground.


Uses

Rapeseed is grown for the production of edible vegetable oils, animal feed, and
biodiesel Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oi ...
. Rapeseed was the third-leading source of vegetable oil in the world in 2000, after
soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu ...
and palm oil. It is the world's second-leading source of
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
meal after soybean.


Vegetable oil

Rapeseed oil is one of the oldest known vegetable oils, but historically was used in limited quantities due to high levels of erucic acid, which is damaging to
cardiac muscle Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle ...
of animals, and glucosinolates, which made it less nutritious in animal feed. Rapeseed oil can contain up to 54% erucic acid. Food-grade oil derived from rapeseed cultivars, known as canola oil or low-erucic-acid rapeseed oil (LEAR oil), has been generally recognized as safe by the United States Food and Drug Administration. Canola oil is limited by government regulation to a maximum of 2% erucic acid by weight in the US and 2% in the EU, with special regulations for infant food. These low levels of erucic acid are not believed to cause harm in human
infants An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used ...
.


Animal feed

Processing of rapeseed for oil production produces rapeseed meal as a byproduct. The byproduct is a high-protein animal feed, competitive with soybean. Rapeseed is an excellent silage crop (fermented and stored in air-tight conditions for later use as a winterfeed). The feed is employed mostly for
cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...
feeding, but is also used for pigs and
poultry Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, qu ...
. However, the high levels of erucic acid and glucosinolates in natural rapeseed oil significantly lowers the nutritional value of rapeseed press cakes for animal feed. Rapeseed meal is mostly used as a soil fertilizer rather than for animal feed in China.


Biodiesel

Rapeseed oil is used as diesel fuel, either as
biodiesel Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oi ...
, straight in heated fuel systems, or blended with petroleum distillates for powering motor vehicles. Biodiesel may be used in pure form in newer engines without engine damage and is frequently combined with fossil-fuel
diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engi ...
in ratios varying from 2% to 20% biodiesel. Owing to the costs of growing, crushing, and refining rapeseed biodiesel, rapeseed-derived biodiesel from new oil costs more to produce than standard diesel fuel, so diesel fuels are commonly made from the used oil. Rapeseed oil is the preferred oil stock for biodiesel production in most of Europe, accounting for about 80% of the feedstock, partly because rapeseed produces more oil per unit of land area compared to other oil sources, such as soybeans, but primarily because canola oil has a significantly lower
gel point In polymer chemistry, the gel point is an abrupt change in the viscosity of a solution containing polymerizable components. At the gel point, a solution undergoes gelation as reflected in a loss in fluidity. Gelation is characteristic of polymeri ...
than most other vegetable oils. Because of the changes to the environment caused by climate change, a 2018 study predicted that rapeseed would become an unreliable source of oil for biofuels.


Other

Rapeseed is also used as a cover crop in the US during the winter as it prevents soil erosion, produces large amounts of biomass, suppresses weeds and can improve soil tilth with its root system. Some cultivars of rapeseed are also used as annual forage and are ready for grazing livestock 80 to 90 days after planting. Rapeseed has a high melliferous potential (produces substances that can be collected by insects) and is a main forage crop for honeybees. Monofloral rapeseed honey has a whitish or milky yellow color, peppery taste and, due to its fast crystallization time, a soft-solid texture. It crystallizes within 3 to 4 weeks and can ferment over time if stored improperly. The low fructose-to-glucose ratio in monofloral rapeseed honey causes it to quickly granulate in the honeycomb, forcing beekeepers to extract the honey within 24 hours of it being capped. As a biolubricant, rapeseed has possible uses for bio-medical applications (e.g., lubricants for artificial joints) and the use of personal lubricant for sexual purposes. Biolubricant containing 70% or more canola/rapeseed oil has replaced petroleum-based chainsaw oil in Austria although it is typically more expensive. Rapeseed has been researched as a means of containing radionuclides that contaminated the soil after the Chernobyl disaster as it has a rate of uptake up to three times more than other grains, and only about 3 to 6% of the radionuclides go into the oilseeds.


Cultivation

Crops from the genus '' Brassica'', including rapeseed, were among the earliest plants to be widely cultivated by mankind as early as 10,000 years ago. Rapeseed was being cultivated in India as early as 4000 B.C. and it spread to China and Japan 2000 years ago. Rapeseed oil is predominantly cultivated in its winter form in most of Europe and Asia due to the requirement of
vernalization Vernalization (from Latin ''vernus'', "of the spring") is the induction of a plant's flowering process by exposure to the prolonged cold of winter, or by an artificial equivalent. After vernalization, plants have acquired the ability to flower ...
to start the process of flowering. It is sown in autumn and remains in a leaf rosette on the soil surface during the winter. The plant grows a long vertical stem in the next spring followed by lateral branch development. It generally flowers in late spring with the process of pod development and ripening occurring over a period of 6–8 weeks until midsummer. In Europe, winter rapeseed is grown as an annual break crop in three to four-year rotations with cereals such as
wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
and
barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...
, and break crops such as peas and beans. This is done to reduce the possibility of pests and diseases being carried over from one crop to another. Winter rape is less susceptible to crop failure as it is more vigorous than the summer variety and can compensate for damage done by pests. Spring rapeseed is cultivated in Canada, northern Europe and Australia as it is not winter-hardy and does not require vernalization. The crop is sown in spring with stem development happening immediately after germination. Rapeseed can be cultivated on a wide variety of well-drained soils, prefers a pH between 5.5 and 8.3 and has a moderate tolerance of soil salinity. It is predominantly a
wind-pollinated Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilo ...
plant but shows significantly increased grain yields when bee-pollinated, almost double the final yield but the effect is cultivar-dependent. It is currently grown with high levels of nitrogen-containing fertilisers, and the manufacture of these generates N2O. An estimated 3–5% of nitrogen provided as fertilizer for rapeseed is converted to N2O.


Climate change

The cultivatable range for rapeseed is both expected to decrease due to climate change, and where rapeseed is grown quality of the crop, in both yield and volume of oil is expected to decrease substantially. Some researchers recommend finding alternative varieties of ''Brassica'' for cultivation.


Diseases and pests

The main diseases of the winter rapeseed crop are '' canker'', light leaf spot (''
Pyrenopeziza brassicae ''Pyrenopeziza brassicae'' is a plant pathogen infecting Brassicaceae (formerly known as Cruciferae). References External links Index FungorumUSDA ARS Fungal Database Fungal plant pathogens and diseases Dermateaceae Fungi described ...
''), alternaria-'' and sclerotinia- stem rots. Canker causes
leaf spot A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions ...
ting, and premature ripening and weakening of the stem during the autumn-winter (fall-winter) period. A conazole- or triazole- fungicide treatment is required in late autumn (fall) and in spring against canker while broad-spectrum fungicides are used during the spring-summer period for alternaria and sclerotinia control. Oilseed rape cannot be planted in close rotation with itself due to soil-borne diseases such as sclerotinia,
verticillium wilt Verticillium wilt is a wilt disease affecting over 350 species of eudicot plants. It is caused by six species of ''Verticillium'' fungi: ''V. dahliae'', ''V. albo-atrum'', ''V. longisporum'', ''V. nubilum'', ''V. theobromae'' and ''V. tricor ...
and clubroot. Transgenic rapeseed shows great promise for .
Transexpression A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change th ...
of a class II chitinase from
barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...
(''Hordeum vulgare'') and a
type I ribosome inactivating protein A ribosome-inactivating protein (RIP) is a protein synthesis inhibitor that acts at the eukaryotic ribosome. This protein family describes a large family of such proteins that work by acting as rRNA N-glycosylase (EC 3.2.2.22). They inactivate ...
into '' B. juncea'' produces a large . Chhikara ''et al.'', 2012 finds that this combination of
transgene A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change t ...
s reduces hyphal growth by 44% and delays disease presentation in '' Alternaria brassicicola'' of ''juncea''.


Pests

Rapeseed is attacked by a wide variety of insects, , as well as wood pigeons. The brassica pod midge (''
Dasineura brassicae ''Dasineura brassicae'', the brassica pod midge, is a rapeseed Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), ...
''), cabbage seed weevil ('' Ceutorhynchus assimilis''), cabbage stem weevil ('' Ceutorhynchus pallidactylus''), cabbage stem flea beetle (''
Psylliodes chrysocephala ''Psylliodes chrysocephala'' or ''Psylliodes chrysocephalus'', commonly known as the cabbage-stem flea beetle, is a species of leaf beetle situated in the subfamily Galerucinae and the tribe Alticini (flea beetles). Description ''P. chrysoceph ...
''), rape stem weevil ('' Ceutorhynchus napi'') and
pollen beetles Pollen beetle is an informal term for any species of beetle associated intimately with suitably pollen-rich species of flowers. Typically such a beetle is adapted to the pollen as a major part of its diet. Species in at least sixteen families of th ...
are the primary insect pests that prey on the oilseed rape crop in Europe. The insect pests can feed on developing pods to lay eggs inside and eat the developing seeds, bore into the plant's stem and feed on pollen, leaves and flowers. Synthetic
pyrethroid A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums ('' Chrysanthemum cinerariaefolium'' and '' C. coccineum''). Pyrethroids are used as commercial and household insecticides. ...
insecticides are the main attack vector against insect pests though there is a large-scale use of prophylactic insecticides in many countries. Molluscicide pellets are used either before or after sowing of the rapeseed crop to protect against slugs.


Genetics and breeding

In 2014 an
SNP array In molecular biology, SNP array is a type of DNA microarray which is used to detect polymorphisms within a population. A single nucleotide polymorphism (SNP), a variation at a single site in DNA, is the most frequent type of variation in the g ...
was released for ''B. napus'' by Dalton-Morgan ''et al.'', and another by Clarke ''et al.'', in 2016, both of which have since become widely used in molecular breeding. In a demonstration of the importance of
epigenetics In biology, epigenetics is the study of stable phenotypic changes (known as ''marks'') that do not involve alterations in the DNA sequence. The Greek prefix '' epi-'' ( "over, outside of, around") in ''epigenetics'' implies features that are ...
, Hauben ''et al.'', 2009 found that isogenic lines did ''not'' have identical energy use efficiencies in actual growing conditions, due to epigenetic differences. Specific locus amplified fragment sequencing ( SLAF-seq) was applied to ''B. napus'' by Geng ''et al.'', in 2016, revealing the genetics of the past domestication process, providing data for genome-wide association studies (GWAS), and being used to construct a high-density linkage map.


History of the cultivars

In 1973, Canadian agricultural scientists launched a marketing campaign to promote canola consumption. Seed, oil, and protein meal derived from rapeseed cultivars which is low in erucic acid and low in glucosinolates was originally registered as a trademark, in 1978, of the Canola Council of Canada, as "canola". This is now a generic term for edible varieties of rapeseed but is still officially defined in Canada as rapeseed oil that "must contain less than 2% erucic acid and less than 30 µmol of glucosinolates per gram of air-dried oil-free meal." Following the European Parliament's Transport Biofuels Directive in 2003 promoting the use of biofuels, the cultivation of winter rapeseed increased dramatically in Europe.
Bayer Cropscience Bayer AG (, commonly pronounced ; ) is a German multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of business include pharmaceutica ...
, in collaboration with
BGI-Shenzhen BGI Group, formerly Beijing Genomics Institute, is a Chinese genomics company with headquarters in Yantian District, Shenzhen. The company was originally formed in 1999 as a genetics research center to participate in the Human Genome Project. It ...
, China, KeyGene, the Netherlands, and the University of Queensland, Australia, announced it had sequenced the entire genome of ''B. napus'' and its constituent genomes present in ''B. rapa'' and ''B. oleracea'' in 2009. The "A" genome component of the amphidiploid rapeseed species ''B. napus'' is currently being sequenced by the Multinational ''Brassica'' Genome Project. A genetically modified-for- glyphosate-tolerance variety of rapeseed which was developed in 1998 is considered to be the most disease- and drought-resistant canola. By 2009, 90% of the rapeseed crops planted in Canada were of this sort.


GMO cultivars

The Monsanto company genetically engineered new cultivars of rapeseed to be resistant to the effects of its herbicide, Roundup. In 1998, they brought this to the Canadian market. Monsanto sought compensation from farmers found to have crops of this cultivar in their fields without paying a license fee. However, these farmers claimed that the pollen containing the ''Roundup Ready'' gene was blown into their fields and crossed with unaltered canola. Other farmers claimed that after spraying Roundup in non-canola fields to kill weeds before planting, ''Roundup Ready''
volunteers Volunteering is a voluntary act of an individual or group freely giving time and labor for community service. Many volunteers are specifically trained in the areas they work, such as medicine, education, or emergency rescue. Others serve ...
were left behind, causing extra expense to rid their fields of the weeds. In a closely followed legal battle, the
Supreme Court of Canada The Supreme Court of Canada (SCC; french: Cour suprême du Canada, CSC) is the Supreme court, highest court in the Court system of Canada, judicial system of Canada. It comprises List of Justices of the Supreme Court of Canada, nine justices, wh ...
found in favor of Monsanto's patent infringement claim for unlicensed growing of ''Roundup Ready'' in its 2004 ruling on '' Monsanto Canada Inc. v. Schmeiser'', but also ruled that Schmeiser was not required to pay any damages. The case garnered international controversy, as a court-sanctioned legitimization for the global patent protection of genetically modified crops. In March 2008, an out-of-court settlement between Monsanto and Schmeiser agreed that Monsanto would clean up the entire GMO-canola crop on Schmeiser's farm, at a cost of about CAN$660.


Production

The
Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
reports global production of in the 2003–2004 season, and an estimated in the 2010–2011 season. Worldwide production of rapeseed (including canola) has increased sixfold between 1975 and 2007. The production of canola and rapeseed since 1975 has opened up the edible oil market for rapeseed oil. Since 2002, production of
biodiesel Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oi ...
has been steadily increasing in EU and U.S. to in 2006. Rapeseed oil is positioned to supply a good portion of the vegetable oils needed to produce that fuel. World production was thus expected to trend further upward between 2005 and 2015 as biodiesel content requirements in Europe go into effect.Canola, Growing Great 2016, The Canola Council of Canada, 2007, page 3, 10 } , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , <, , <, , <, , <, , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , <, , <, , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , N/A, , N/A, , N/A, , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , <, , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , <, , <, , <, , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , N/A, , N/A, , N/A, , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , , , N/A, , N/A, , N/A, , , , , , , , , , , , , , , , , , , , , , , , , - style="text-align:right;" , style="text-align:left;" , World Total, , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,


See also

*
Triangle of U The triangle of U ( ) is a theory about the evolution and relationships among the six most commonly known members of the plant genus ''Brassica''. The theory states that the genomes of three ancestral diploid species of ''Brassica'' combined to ...


Explanatory notes


References


Citations


General sources

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *


External links

* * {{Authority control Asian vegetables Brassica Crops Edible nuts and seeds Energy crops Fodder Leaf vegetables Medicinal plants Plants described in 1753