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The development of soybean, sunflower, and canola, the three most significant edible oils for temperate climates, represent important new crop successes (Robinson 1973; Hymowitz 1990; Downey 1990). It is likely that these crops will continue to expand in hectarage, given increasing demand for high quality edible oils and meals, the wide adaptation of these crops, and new, improved cultivars. However, each of these major oilseeds has its limitations. For example, soybean, though ideal for most regions of the corn belt, is not well adapted to more northerly regions of North America, Europe, and Asia. Canola and sunflower are better adapted to northern climates but have high nitrogen requirements (especially canola), and are susceptible to insect or bird predation as well as diseases. These oilseed crops are not often suitable to marginal lands (low moisture, low fertility, or saline soils). In recent years, there has been increasing interest in developing agronomic systems with low requirements for fertilizer, pesticides, and energy, and which provide better soil erosion control than conventional systems (NRC 1989). This led us to examine the viability of developing camelina as an oilseed with reduced input requirements and as a crop well suited to marginal soils, or soil- and resource-conserving agronomic practices.Fig. 1) and has branched smooth or hairy stems that become woody at maturity. Leaves are arrow-shaped, sharp-pointed, 5 to 8 cm long with smooth edges. It produces prolific small, pale yellow or greenish-yellow flowers with 4 petals. Seed pods are 6 to 14 mm long and superficially resemble the bolls of flax. Seeds are small (0.7 mm x 1.5 mm), pale yellow-brown, oblong, rough, with a ridged surface. Morphology and distribution of camelina species has been described by Polish and Russian botanists (Mirek 1981). Camelina has been shown to be allelopathic (Grummer 1961; Lovett and Duffield 1981).
Camelina is listed as being adapted to the flax-growing regions of the northern Midwest (Minnesota, North Dakota, South Dakota) (NC-121 1981). It is primarily a minor weed in flax and not often a problem in other crops and does not have seed dormancy (Robinson 1987). However, the adaptation of camelina as a crop has not been widely explored. Similar to the other Cruciferous species, it is likely best adapted to cooler climates where excessive heat during flowering is not important. There are several winter annual biotypes available in the germplasm, and it is possible that camelina could be grown as a winter crop in areas with very mild winters. Camelina is short-seasoned (85 to 100 d) so that it could be incorporated into double cropping systems during cool periods of growth, possibly in more tropical environments.
Camelina declined as a crop during medieval times due to unknown factors, but continued to coevolve as a weed with flax, which probably accounts for its introduction to the Americas. Like rapeseed oil, camelina oil has been used as an industrial oil after the industrial revolution. The seeds have been fed to caged birds, and the straw used for fiber. There have been scattered hectarages in Europe in modern times, mostly in Germany, Poland, and the USSR, and some efforts were made in the 1980s at germplasm screening and plant breeding (Enge and Olsson 1986; Seehuber and Dambroth 1983; Seehuber and Dambroth 1984: Kartamyshev 1985). Camelina has been evaluated to some extent in Canada (Downey 1971) and to a larger extent in Minnesota where R.G. Robinson conducted agronomic studies on camelina (Robinson 1987). However, there has been relatively little research conducted on this crop worldwide, and its full agronomic and breeding potential remains largely unexplored.Table 1), but it differed in seed size, maturity, lodging resistance, and oil percentage. Yields of camelina cultivars (Table 2) have been in the 600 to 1,700 kg/ha range at Rosemount, Minnesota (45° N latitude), averaging about 1,100 to 1,200 kg/ha over many years of trials. It should be noted that the yield of many of these oilseeds (especially B. napus) has been improved significantly through plant breeding and improved agronomic practices, whereas camelina has largely not had the benefit of plant breeding. Under Minnesota conditions, yields of all spring-sown cruciferous oilseeds are much higher at more northerly locations (1,736 kg/ha long term average canola yield--Roseau, Minnesota), compared with yields at Rosemount, which is located near St. Paul. Camelina is much smaller seeded and earlier maturing than the other cruciferae tested. Lodging was comparable to or fact slightly superior to the other cruciferae oilseeds tested (Table 1), and there was significant variation for lodging among camelina varieties (Table 2).
Some variation in camelina maturity, lodging resistance, seed weight, and oil percentage was exhibited by the lines tested and by other germplasm screening not reported here, but many of these lines were similar in yield at Rosemount (Table 2). Certainly increases in yield might be generated through plant breeding. German plant breeders using the single-seed descent method, have found transgressions over parental lines in many yield traits for camelina, demonstrating both the high yield potential and capacity for yield improvement in this species (Seehuber et al. 1987). This experience indicates that camelina, unlike some wild species undergoing domestication, exhibits yield potential and oil content which are both currently agronomically acceptable and amenable to improvement through plant breeding.Table 3). In one four-year study, crops were sown with standard farm machinery on large plots. Camelina was sown in late fall on stubble, without seedbed preparation or herbicides, or conventionally in the spring and compared with flax sown conventionally and sprayed with herbicides (dalapon and MCPA). Performance of winter-sown camelina was equal or superior to conventionally-sown flax in these studies.
To confirm these results, a separate two-year study was conducted where camelina and flax were surface-seeded by hand in both winter and spring on tilled or stubble ground, broadcast or by machine without herbicides (Table 4). In 1990-91, surface seeding in winter was unsuccessful with flax, but was successful with camelina, producing significantly earlier emergence and fewer weed problems. However, in the 1989-90 study, the winter seeding was unsuccessful for both crops, probably due to an open winter. Surface seeding of camelina seemed to work better under no-till conditions, possibly due to superior microsite protection for the small seed and seedling, and prevention of wind dispersion of the seed. Machine planting was no better than broadcasting in the spring sowings. Machine planting in December was not feasible. A winter-sown stand of camelina emerges mid-April in Minnesota, before most other spring-sown crops, and before significant weed flushes.
These trials showed that camelina sown without herbicide or tillage yielded as well or better than flax grown conventionally. These studies also showed that camelina, unlike flax, can be surface-sown on frozen ground in the late fall or winter or early spring and produce good stands and yields comparable to conventionally-sown Cruciferae crops.Table 5). In this and in subsequent studies (Robinson 1987), camelina has produced better stands, weed control, and yields when planted in the winter with a cover crop compared with seeding after conventional tillage in the spring or surface seeding on bare ground in the fall. These data indicate that camelina is highly compatible with cover crops used for fall and early spring soil erosion control.
Bramm et al. (1990) found that camelina was better able to compensate for early water deficits than flax or poppy. This drought-avoidance characteristic might make camelina better suited to drier regions than other oilseeds.
Downy mildew (Peronospora camelinae), a white or gray mold on the upper part of the stem is sometimes observed in camelina (Robinson 1987). Transmission of Turnip Yellow Mosaic virus by camelina seed has been reported (Hein 1984). However, camelina has been reported to be highly resistant to blackleg (Lepotosphaeria maculans) which is a significant disease problem with canola (Salisbury 1987). Camelina has also been found to be very resistant to Alternaria brassicae, compared with turnip rape or swede rape (Grontoft 1986; Conn et al. 1988).
Flea beetle [Phyllotreta cruciferae (Goeze)] is also sometimes observed on camelina, although it is not nearly the problem it is with canola. However, in extensive multi-year small-plot trials, damage due to insects and diseases in camelina have not been sufficient to warrant control measures (Robinson 1987).
Perennial or biennial weeds are likely to be more difficult to control in camelina. However, the competitiveness of camelina with annual weeds presents the possibility that camelina could be grown both without tillage and without preemergence weed control, both significant costs of production and environmental risk-factors.Table 2), but the germplasm has not been widely characterized. Studies in Germany have shown oil content to range between 37 and 41% and seed protein content 23 to 30% (Marquard and Kuhlmann 1986). Camelina appears to be similar in protein content and elemental composition to flax (Linum usitatissimum L.), with the exception of a higher sulfur content (Robinson 1987). Camelina meal is comparable to soybean meal, containing 45 to 47% crude protein and 10 to 11% fiber (Korsrud et al. 1978).
Zero to trace levels of volatile isothiocyanates have been found in camelina meal (Peredi 1969; Korsrud et al. 1978; Sang and Salisbury 1987) compared with crambe (Crambe abyssinica Hochst) or industrial rapeseed meal which contains substantially higher levels of glucosinolates. Laboratory mice fed camelina meal gained less weight than those fed casein or egg control diets, but more than those fed crambe meal (Korsrud et al. 1978). Although some essential amino acids may have been limiting in the camelina meal diets, some growth depressing factor other than glucosinolates may have been present (Korsrud et al. 1978).
Camelina has been fed to wild (Fogelfors 1984) or caged (Mabberly 1987) birds, and this is one potential use. Other potential uses include applications as an ornamental, a cover or smother crop, a border row for experimental field plots, or in dried flower arrangements (Robinson 1987).Fig. 2). About 54% of the fatty acids are polyunsaturated, primarily linoleic (18:2) and linolenic (18:3), and 34% are monounsaturated, primarily oleic (18:1) and eicosenoic (20:1) (Table 6).
Our values for fatty acid composition of Camelina sativa are generally similar to those reported for Camelina rumelica (Umarov et al. 1972), or other reports on Camelina sativa (Seehuber and Dambroth 1983). With its low saturated fat content camelina oil could be considered a high quality edible oil, but it is also quite highly polyunsaturated, which makes it susceptible to autoxidation, thus giving it a shorter shelf life. With an iodine value of 144, it is classified as a drying oil (Robinson 1987). Camelina oil has been used as a replacement for petroleum oil in pesticide sprays (Robinson and Nelson 1975).
Camelina oil is less unsaturated than linseed (flax) oil and more unsaturated than sunflower or canola oils (Fig. 2, Table 6). The balance of saturated vs. unsaturated fats is similar to that of soybean, but camelina contains significantly higher proportion of C18:3 fatty acids. Camelina seems to be unique among the species evaluated in having a high eicosenoic acid content in the oil, but the potential value or disadvantage of this is currently unclear.
The erucic acid content is probably too low for use in the same applications as crambe or high erucic acid rapeseed, where a high erucic acid content is desired. Most of the camelina lines evaluated contain 2 to 4% erucic acid (Table 6), which is greater than the maximum (2%) limits for canola-quality edible oil. However, in a preliminary germplasm screen, we have identified lines with zero erucic acid content (data not shown), so it is likely that this trait could readily be removed through plant breeding, as it has been with canola.
The lack of clear utilization patterns for camelina oil currently limit its use. The fatty acid composition does not currently uniquely fit any particular use. Manipulation of camelina fatty acid content, which has been achieved in other oilseeds, could greatly improve the utilization possibilities of this crop.
The research reported here has shown that camelina possesses unique agronomic traits which could substantially reduce and perhaps eliminate requirements for tillage and annual weed control. The compatibility of camelina with reduced tillage systems, cover crops, its low seeding rate, and competitiveness with weeds could enable this crop not only to have the lowest input cost of any oilseed, but also be compatible with the goals of reducing energy and pesticide use, and protecting soils from erosion. Camelina is a potential alternative oilseed for stubble systems, winter surface seeding, double cropping, or for marginal lands. At a seeding rate of 6 to 14 kg/ha, camelina could be inexpensively applied by air or machine-broadcast in early winter or spring on stubble ground without special equipment. Although these unimproved lines have been shown to be agronomically acceptable, modern history has indicated the Cruciferae to be highly manipulatable through plant breeding or biotechnology, and so the promise of improvement is also high. The meal does not contain glucosinolates, but the fatty acid composition of the seed needs to be modified to provide a role for the crop in the oilseeds market.
Lack of clear utilization patterns currently limit the crop, and further work on oil, meal, and seed use is required. The possibilities of using camelina in human food, as birdseed, as an edible or industrial oil, a fuel, or other applications remains largely unexplored. Further utilization and breeding research is required to more fully make use of the unique agronomic qualities that this crop possesses.
|Species||Yield (kg/ha)y||Oil (%)||Seed size (g/1,000 seeds)||Maturity date||Lodging (%)|
|Days from planting to|
|Line (origin)||Full bloom||Maturity||Height (cm)||Lodging ratingz||1,000 seed weight (g)||Seed yield (kg/ha)||Oil (%)|
|Seed yield (kg/ha)|
|Cropz||Sowing date||Sowing rate (kg/ha)||Tillage||Weed control (%)y||1970||1971||1972||1973||Ave.|
|Days from planting to|
|Treatments||Stand (%)||Full bloom||Maturity||Lodging ratingz||Weeds (%)y||Height (cm)||Seed yield (kg/ha)|
|Flax winter scatter||4||6/15||7/21||1||100||52||91|
|Flax spring scatter||35||6/15||7/22||1||75||51||801|
|Flax spring machine||98||6/15||7/22||1||61||47||851|
|Camelina winter scatter||93||6/1||6/28||1||16||59||749|
|Camelina spring scatter||64||6/9||7/7||1||48||41||1008|
|Camelina spring machine||100||6/13||7/12||2||63||52||888|
|Flax winter scatter||3||6/14||7/21||1||100||51||142|
|Flax spring scatter||68||6/12||7/21||1||80||56||837|
|Flax spring machine||100||6/14||7/21||2||85||53||937|
|Camelina winter scatter||71||6/1||6/30||2||51||60||850|
|Camelina spring scatter||95||6/12||7/8||2||34||57||1147|
|Camelina spring machine||98||6/11||7/9||2||42||55||865|
|Seed yield (kg/ha)|
|Treatment||Stand (%)||Maturity||Weed control (%)z||Lodging (%)||1971||1972||1973||Ave.|
|No cover crop||77||7/11||78||37||840||1243||1747||1277|
|Flax cover crop||89||7/9||83||18||1120||1176||1870||1389|
|Fatty acid content (% of oil)|
Fig. 1. Camelina plant nearing maturity. Camelina superficially resembles flax.
Sustainable Oils has sown the seeds of change for farmers in the northwestern US and Canada with extensive research. Of the more than 90 accessions of seed lines tested, SO-10, SO-20 and SO-30, were selected to be sold in 2009 because they have high yield potential and good agronomic characteristics. See how they stack up to the most common public variety:
Grain Yield and Agronomic Characteristics in Camelina Varieties
Average values from field experiments in 12 environments in Montana, USA, Saskatchewan and Alberta, Canada, 2006, 2007.
SO-10 | SO-10 is a spring-type camelina. It is a short variety with increased early vigor, early flowering and extended seed filling period. SO-10 has high yield potential with good adaptability to high yielding environmental conditions. This variety has a high test weight (52.3 Lb/Bu), heavy seed weight (1.12 g/1000 seeds) and average seed oil content (36.7%).
SO-20 | SO-20 is a spring-type camelina. It is a short variety with early flowering. SO-20 has high yield potential with good response to diverse environmental conditions. The variety has an average test weight (51.4 Lb/Bu) seed weight (1.07 g per 1000 seeds) and seed oil content (36.8%).
SO-30 | SO-30 is a spring-type camelina. SO-30 is a short variety with early flowering and an extended seed filling period. SO-30 has a high yield potential with a very good adaptability to a broad range of environmental conditions. SO-30 has increased test weight (52.4 Lb/Bu), heavy seed weight (1.11 g per 1000 seeds) and high seed oil content (37.1%).