Environmental Engineering Reference
In-Depth Information
taBle 2.2
Genomes of some Potential energy crop species
species
Genome size (pg)
a
Genome sequence
Sorghum
0.75
Patterson et al. 2009
Maize
2.73
www.maizegdb.org
Sugarcane
7.0 (Edme et al. 2005)
Saccharum officinarum
4.05
Saccharum spontaneaum
3.15
Poplar (
Populus trichocarpa
)
0.5
Tuskan et al. 2006
Eucalyptus (
Eucalyptus globulus
)
0.58
www.eucagen.org
Willow (
Salix fragilis
)
0.86
a
From http://data.kew.org/cvalues.
2.13.2 S
ugarcanE
(
and
c
loSE
r
ElativES
)
Sugarcane is a very efficient C
4
plant grown in tropical and subtropical regions (Henry 2010).
Sugarcane (a
Saccharum
hybrid) is probably the leading industrial crop internationally with signifi-
cant amounts being used for ethanol production and electricity generation. Sugarcane is currently a
first-generation biofuel crop with the sugar being used to produce ethanol on a large scale. Sugarcane
was first domesticated for the high sugar content of the canes, but development of sugarcane as an
energy crop may result in the selection of plants for biomass yield rather than sugar content, result-
ing in a reduced sugar content.
Close relatives of sugarcane such as
Miscanthus
(Yamada and Henry 2011) may also have potential
as energy crops. Hybrids between sugarcane and other species within the
Saccharum
complex (e.g.,
Miscanthus
and
Erianthus
species) may provide important options for the development of energy
crops. Molecular tools will be essential to the efficient introgression of genes from these other species.
2.13.3 m
aizE
Maize is a major food crop with most maize being used to feed farmed animals. The development
of maize as an energy crop or as a dual-purpose food and energy crop will be greatly advanced by
applications of genomics. The protein residue remaining after converting the grain carbohydrates
to ethanol has become a key animal feed ingredient. Genomics approaches may be used to improve
the nutritional value of this protein. Maize may be a useful model genome for grass improvement
for bioenergy (Carpita and McCann 2008).
2.13.4 o
thEr
g
raSSES
Most grasses have been domesticated and used for food and pasture production. The many grass
species (more than 10,000 worldwide) may include species overlooked for these uses but that have
potential as energy crops. Species such as switchgrass (
Panicum virgatum
), a native grass from
North America, are being intensely evaluated as potential bioenergy crops (McLaughlin et al.
1999). Analysis of grasses that might suit bioenergy production in specific environments may iden-
tify many new options for domestication.
2.13.5 p
oplar
The poplar is a fast-growing woody biomass option for many temperate and cooler climates. The
poplar genome has been sequenced by Tuskan et al. (2006). Willows (
Salix
species), a closely related
