As the world searches for alternative sources of energy so as to
ween ourselves off the dependancy on petroleum that pollutes our
environment and puts our economy in a stranglehold, biofuel has
become a very possible replacement. It has been a succes story in
Brazil where ethanol is made from sugar cane. In the United States
we produce nearly as much 8100 million liters compared to 11200
million liters in Brazil. A lot of that could be used in a mixture with
diesel fuel to create less potent emissions.
Biofuel is a renewable resource it is
produced from the fermentation of
all the saccharine products of plant
biomass to produce ethanol.
Ethanol can also be produced from
the waste products of the
agriculture and forestry industries
Cellulosic ethanol technology can be
a low cost producer of ethanol
however it has not been proven
commercially and those first of a
kind facilites would have a high
Biofuel crops are chosen
for high cellulose content,
Ease of growth, and
Cellulosic ethanol technology has 4 steps: pretreatment, processing, fermentation,
Its actually a lot more complicated than that and depending on what kind of crop you are
using the process is somewhat different.
In the case of sweet sorghum it is separated out into its different biological parts. The juice
is separated from the solid residuals (lignin and bargasse) the bargasse is the component
that contains the cellulose and hemicellulose
Afterwards each of these distinct parts are either used directly in fermentation or treated
(enzyme or acid hydrolisis) to create monosaccharides and then fermented to create
Finally all of the ethanol produced is distilled to produce the final product
Sweet sorghum is a plant that comes
from Africa and is related to sugar cane.
They both produce sugar products.
Sweet sorghum has been cultivated
around the world in many different
countries on different continents
Sweet sorghum is characterized by wide
adaptability, drought tolerence,
waterlogging tolerance, saline-alkali
tolerance, rapid growth, and high
The stalk is processed to produce syrup,
molasses, sugar, hay for feeding animals,
and also biofuel
Biofuel is such a high capital venture.
Sweet sorghum has been hypothesized to
reduce the economic trade offs by
burning the lignin for heat and electricity,
possibly extracting the juice, and selling
it as high quality sugar syrup.
Identification of QTL for Sugar-Related Traits in a Sweet
x Grain Sorghum (Sorgum Bicolor L. Moench)
Recombinant Inbred Population
QTL for stem sugar related and other traits were identified in a
sweet x grain sorghum population.
QTL analyses were done using phenotypic data for 11 different
traits measured in two field tests and a genetic map comprising
228 SSR and AFLP markers grouped into 16 linkage groups, of
which 11 could be assigned to the 10 sorghum chromosomes.
QTL for all sites were generally co-located to 5 locations: SBI-
01, SBI-03, SBI-05, SBI-06, SBI-10
Increase in stem sugars and dry matter yield are important to
sweet sorghum breeding
The sorghum inbred lines R1988 andR9403463-2-1 were
crossed to create a recombinant inbred line
The progeny of this line and the parent lines were all cultivated
until flowering and then the stem height and flowering time
6 weeks after antithesis a good sample of the crop was
harvested a fresh weight was recorded. The leaves, stems, and
panicles were partitioned and the weight of each was also
A subsample of stems was milled and the percentage of soluble
solids (Brix) was measured using a refractometer.
A second subsample of the juice was analysed for fructose,
sucrose, glucose content using high performance liquid
DNA was isolated from 4-week old plants that were
snap frozen and then extracted using the CTAB
AFLP and SSR markers were identified and classified
as having come from one parent, the other, or both
Linkage analysis was done using MultiPoint software
and marker order was compared to previously
QTL analysis was done for both field tests to search
for sugar-related and agronomic traits
All sugar-related traits were highly correlated with each other
Plant height was positively correlated with sugar-related traits
Grain yield was negatively correlated with sugar-related traits
Flowering time and dry matter were significantly correlated with
Total dry matter was also highly correlated with grain yield
Using MultiPoint 247 polymorophic bands produced by 28 AFLP
primer pairs, 42 Xtsp microsatellite, and 10 sugarcane
microsatellite markers created the map above
The MultiPoint map was used to identify sugar-related and other
Sugar-related and Agronomic
Higher glucose content was associated with SBI-07 alleles from R9403943-
Higher fructose content was associated with alleles SBI-06 alleles from
R9188 and SBI-07 alleles from R9403943-2-1 that colocated with those
controlling glucose content
Higher sucrose yield was associated with 3 genomic regions: SBI-05, SBI-
06, SBI-10 with two from R9188 (SBI-05, SBI-06) and the other from
High Brix content was associated with SBI-05 and SBI-06 and all alleles
came from R9188
Height was associated with 3 genomic regions 2 (SBI-05, SBI-06) from
R9188 and 1 (SBI-10) from R9403943-2-1
For flowering time 4 genomic regions were identified 2 (SBI-01, SBI-10)
from R9188 and 2 (SBI-04, SBI-06) from R9403943-2-1
3 genomic regions are associated with total dry matter(SBI-01, SBI-06,SBI-
10) SBI-06 contains regions from both parents and the other to are from
The final trait measured was grain yield which was associated with 3
genomic regions (SBI-2, SBI-03, SBI-10) SBI-02 was from R9188, SBI-10
was from R9403943-2-1, while SBI-03 shared markers from both parents
Dauriat, A., & Wyman, C. (2005). Refining sweet sorghum to
ethanol and sugar: economic trade-offs in the context of North China.
BIORESOURCE TECHNOLOGY, 96(9), 985-1002.
Seth C. Murray, William L. Rooney, Martha T. Hamblin, Sharon E.
Mitchell, and Stephen Kresovich (2009). Sweet Sorghum
Genetic Diversity and Association Mapping for Brix and HeightPlant
Gen. March 2009 2:48-62; doi:10.3835/plantgenome2008.10.0011
Jordan, D., Chapman, S., Godwin, I., Mace, E., & McIntyre, C.
(2008). Identification of QTL for sugar-related traits in a sweet x
grain sorghum (Sorghum bicolor L. Moench) recombinant inbred
population. MOLECULAR BREEDING, 22(3), 367-384.
Dolat, A., Steinberger, Y., Wang, X., Osman, A., & Xie, G. (2009).
Biomass yield and changes in chemical composition of sweet
sorghum cultivars grown for biofuel. Field Crops Research, 111(1-2),