''Crambe abyssinica'' is an annual oilseed crop of the family

Brassicaceae Brassicaceae () or (the older) Cruciferae () is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The leav ...

. It is mainly cultivated due to the high levels of

erucic acid Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22:1ω9. It has the chemical formula CH3(CH2)7CH=CH(CH2)11COOH. It is prevalent in wallflower seed and other plants in the family Brassicaceae, with a reported content of 20 to 54% i ...

that are contained in its seeds. The crambe oil is used for industrial purposes and its side products can be partly used as animal feed.

Botany

''Crambe abyssinica'' has its origins in eastern

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

and was domesticated in the Mediterranean region. It grows up to a height between , depending on field conditions. Its cropping cycle is rather short, ranging from 90 to 100 days. Usually, its straight stalk is moderately branched and its leaves are of an oval shape. The plant's flowers are small and white, arranged in racemes and have four free

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s, four free alternating petals, two shorter and four longer free stamens, what is typical for

. Mostly, these flowers are self-pollinated, but some cases of cross-

pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...

have been observed. Its

indehiscent Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...

fruits enclose only one spherical seed that contains around 26% protein, 18% fibre and 35% oil. This oil content is lower than what can be extracted from

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), cultivated mainly for its oil-rich seed, which naturally contains a ...

and the oil is not edible. The pericarp of the seed usually adheres to the seed even at harvest.

History of agricultural use and cultivation

Crambe has not been in cultivation for a long time. It was probably cultivated for the first time in the 1930s in the former

USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...

. Later the crop was tested in other regions of the USSR, in Sweden and in Poland, where crambe was grown on 25,000 ha (~62,000 acres) after the second world war. Research efforts in northern and eastern Europe were increased and the agronomical characteristics and industrial uses of crambe were intensively studied. By successive selection within ''C. abyssinica,'' conventional

breeding Breeding is sexual reproduction that produces offspring, usually animals or plants. It can only occur between a male and a female animal or plant. Breeding may refer to: * Animal husbandry, through selected specimens such as dogs, horses, and ra ...

started in the 1950s in some European countries. Hereby improved strains were introduced to Canada and the United States. Further selection and crossing of different accessions led to the release of new varieties in the 1970s. Through introgression of wild populations and mass selection two new cultivars were created in the 1980s which were promoted as high yielding sources of erucic acid. In the 1990s a breeding program was started in the Netherlands. Nevertheless, after a period of great efforts to bring crambe into extended cultivation, interest in the crop in Europe has declined in recent years.

Cultivation

With a germination temperature of which is also equivalent to the basal growing temperature, ''C. abyssinica'' is a winter crop in southern Europe and subtropical areas whereas it is cultivated as spring crop in northern Europe and more continental areas. The optimal growing temperature is approximately . It tolerates annual average temperature between and frost down to . Because of its ability to get along with only of precipitation, ''C. abyssinica'' is considered to be relatively

drought tolerant Drought tolerance is the ability to which a plant maintains its biomass production during arid or drought conditions. Some plants are naturally adapted to dry conditions'','' surviving with protection mechanisms such as desiccation tolerance, deto ...

. Nevertheless, drought stress during the development stages of flowering and grain filling reduces productivity. Cultivation is possible up to an annual precipitation of . Crambe has modest demands regarding soil properties, it tolerates soil pH from 5.0 to 7.8. Low soil depth and a high stone and gravel content decrease drought tolerance. Seeds of many improved varieties are available on the market and are sown at a rate of approximately and at a depth of . Seed maturation is uniform and the 1000 seed weight varies between . Management procedures from sowing to harvesting can be conducted largely with the same machinery used for common cereals. Yield levels vary widely between in Russia, in the U.S. and in Germany. ''Crambe abyssinica'' can be easily inserted in

crop rotation Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant ...

s with a requirement of 1600

growing degree-day Growing degree days (GDD), also called growing degree units (GDUs), are a heuristic tool in phenology. GDD are a measure of heat accumulation used by horticulturists, gardeners, and farmers to predict plant and animal development rates such as the ...

s. Its rotation contingent should not exceed 25%. Because of similar soil requirements and increased soil borne pathogen pressure, cultivation directly after other

species should be avoided. Also to be avoided is cultivation after artificial grassland and fallows because these will enrich the

soil seed bank The soil seed bank is the natural storage of seeds, often dormant, within the soil of most ecosystems. The study of soil seed banks started in 1859 when Charles Darwin observed the emergence of seedlings using soil samples from the bottom of a lak ...

with weeds and there are few pre-emergence weed management methods available.

Use

''Crambe abyssinica'' is cultivated for a wide range of industrial purposes. The interest lies mainly in the high

content (55-60%) of its seed oil, and makes the crop a competitive option to other

oil plants Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fats ...

as industrial

. The composition of crambe oil gives this product several special traits, such as high smoke point, good wettability of different materials and high viscosity. In addition, its oil has a higher

biodegradability Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradati ...

than

mineral oil Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils. The name 'mineral oil' by itself is imprecise, ...

s. Therefore, erucic acid derived compounds are used as additives in the plastic industry, high temperature hydraulic fluids, waxes, base for paints and coatings, lubricants and many other products. Furthermore, the extracted seed oil is used in pharmaceutical products and cosmetics. The crambe meal, which is a side product of industrial oil production, can be used as a protein supplement for animal feed. It contains approximately 46% proteins, which are of high nutritional quality. Unfortunately, the crambe seed shred also contains toxic compounds such as glucosinolates,

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

s and

inositol phosphate Inositol phosphates are a group of mono- to hexaphosphorylated inositols. They play crucial roles in diverse cellular functions, such as cell growth, apoptosis, cell migration, endocytosis, and cell differentiation. The group comprises: * inosito ...

. The use as forage is therefore very limited. The incorporation rate of crambe by-products into animal feed should not be higher than 5% for growing-finishing

pig The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus ...

s, 15% for

dairy cows Dairy cattle (also called dairy cows) are cattle bred for the ability to produce large quantities of milk, from which dairy products are made. Dairy cattle generally are of the species '' Bos taurus''. Historically, little distinction was m ...

, and 19% for sheep. It is not recommended to feed poultry. A possible new use for crambe could be biofuels since the oil composition is suitable for processing.

Current and future breeding efforts

Genetically, ''C. abyssinica'' has a set of 2n=90 chromosomes and is

hexaploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contain ...

. However, it shows low genetic variation in important agronomic traits, e.g.

content. Thus, improvement of cultivars through selection is difficult to achieve. A new source of variation could be found in the related taxon ''Crambe hispanica''. Recent efforts are found in the field of gene technology. To overcome the limited genetic variation, gene technology has been used in recent years to improve different important agronomic traits of crambe.

Site-directed mutagenesis Site-directed mutagenesis is a molecular biology method that is used to make specific and intentional mutating changes to the DNA sequence of a gene and any gene products. Also called site-specific mutagenesis or oligonucleotide-directed mutagenesi ...

could be another tool for further improvement of the crop. However, the genetic control of many agronomic traits are unknown, thus the potential for genetic improvement is limited at the moment. Additionally further research aims to assess the potential of using the seed cake in protein-based plastic production and to find further uses for the whole plant.

References

External links

Alternative Field Crops Manual
{{Taxonbar, from=Q369867 Brassicaceae Flora of Africa Flora of Europe