Camelina sativa: For Biofuels and Bioproducts - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 157

consumption [ 1 , 2 ]. Interest in camelina as a biofuel feedstock stems from its
drought tolerance and compatibility with existing cropping systems.
In the United States, camelina can be incorporated into a dryland winter wheat-
based cropping system where it can be treated as a summer annual or a fall-seeded
annual [ 3 ]. Camelina is a small-seeded crop and can be broadcast or direct seeded
using existing wheat or canola planting equipment at a shallow depth of no more
than 12 mm, with 6.3 mm being optimal [ 3 ]. The optimal seeding rate has been
found to be 5.6-7.8 kg ha 1 depending on planting conditions such as seed bed
quality, soil humidity, and pressure from weed competition [ 4 ]. No-till conditions
are appropriate for camelina planting, although there are some weed-control issues
that arise from this method of planting due to the lack of herbicide-resistant
varieties [ 5 ].
There are two types of camelina varieties: winter varieties that are planted in the
fall and allowed to overwinter in the rosette stage (fall-seeded) and those that do not
have a vernalization requirement (spring-seeded) [ 12 ]. Fall-seeded varieties have a
growth cycle similar to wheat in that they establish a stand and overwinter in a
dormant stage. Of course, this is dependent on the presence of fall rains. Spring-
seeded camelina does best when planted early [ 3 , 6 ]. If camelina is planted in early
March before weed emergence, it will have enough time to allow it to compete
more vigorously with spring weeds [ 3 , 5 ]. Camelina is a short-season crop, requir-
ing roughly 80 days to reach maturity. Early spring planting or late winter planting
will allow camelina to mature before high summer temperatures cause heat stress
and lower yields [ 7 ]. The required cumulative growing degree days (GDD) for
camelina are estimated to be 1,300 [ 8 ]. The optimal temperature for germination is
3.3 C and delay of planting fromMarch until April results in yield reductions of up
to 25 % due to heat stress [ 6 ]. Dryland trials of camelina in Colorado have
demonstrated superior yields compared to other oilseed crops such as canola [ 9 ,
10 ]. The seed oil content of camelina ranges from 30 to 45 % [ 1 , 10 , 11 ]. The
protein content ranges from 39.2 to 47.4 %/DM, while the fiber content varies from
12.5 to 16.8 % f.f. DM [ 11 ].
Although camelina is a low-input new oilseed crop, it responds well to fertili-
zation [ 12 ]. A general rule of thumb is that camelina needs 2-2.7 kg of N to produce
45 kg of seeds [ 13 ]. This can be applied during the growing season, or if residual
nitrogen is available from previous crops, this can be utilized by the plant as
well [ 13 ].
The flowers of camelina are generally autogamous and are between 5 and 7 mm
in diameter [ 1 ]. These flowers become silicles which vary in number between
126 and 283 [ 14 ]. Each silicle can contain between 10 and 15 seeds [ 1 , 14 ].
During growth, camelina is not susceptible to insect pressure from flea beetles
(Chrysomelidae) that have been shown to negatively affect yields of canola and
Brassica juncea [ 1 ]. The resistance to flea beetles is thought to be the result of
defense compounds present in the leaves of camelina. A class of compounds known
as quercetin glycosides has been identified as contributing to its resistance to
damage from the crucifer flea beetle [ 15 ]. The presence of additional leaf com-
pounds means that camelina is naturally resistant to some fungal infections, which