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BioFuel 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. Renewable Resource 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 capital risk Biofuel Crops Sugar Cane Switchgrass Poplar Sweet Sorghum Maize Biofuel crops are chosen for high cellulose content, Ease of growth, and resiliency Processing Cellulosic ethanol technology has 4 steps: pretreatment, processing, fermentation, distillation 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 ethanol Finally all of the ethanol produced is distilled to produce the final product Sweet Sorghum 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 biomass. 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 Methods 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 were measured 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 recorded 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 chromatography. Genetic Mapping DNA was isolated from 4-week old plants that were snap frozen and then extracted using the CTAB method 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 published maps QTL analysis was done for both field tests to search for sugar-related and agronomic traits Results 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 sugar-related traits 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 agronomic traits Sugar-related and Agronomic Traits Higher glucose content was associated with SBI-07 alleles from R9403943- 2-1 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 R9403943-2-1 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 R9403943-2-1 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 References 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), 55-64.
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