Opportunities and roadblocks in utilizing forages and small grains for liquid fuels

Abstract

Sarath, Gautam; Mitchell, Robert B.; Sattler, S. E.; Funnell, Deanna L.; Pedersen, Jeffrey F.; Graybosch, Robert A.; and Vogel, Kenneth P., "Opportunities and roadblocks in utilizing forages and small grains for liquid fuels" (2008 Abstract This review focuses on the potential advantages and disadvantages of forages such as switchgrass (Panicum virgatum), and two small grains: sorghum (Sorghum bicolor), and wheat (Triticum aesitvum), as feedstocks for biofuels. It highlights the synergy provided by applying what is known from forage digestibility and wheat and sorghum starch properties studies to the biofuels sector. Opportunities therefore, exist to improve biofuel qualities in these crops via genetics and agronomics. In contrast to cereal crops, switchgrass still retains tremendous exploitable genetic diversity, and can be speciWcally improved to Wt a particular agronomic, management, and conversion platform. Combined with emerging studies on switchgrass genomics, conversion properties and management, the future for genetic modiWcation of this species through conventional and molecular breeding strategies appear to be bright. The presence of brown-midrib mutations in sorghum that alter cell wall composition by reducing lignin and other attributes indicate that sorghum could serve as an important model species for C 4 -grasses. Utilization of the brown-midrib traits could lead to the development of forage and sweet sorghums as novel biomass crops. Additionally, wheat crop residue, and wheat and sorghum with improved starch content and composition represent alternate biofuel sources. However, the use of wheat starch as a biofuel is unlikely but its value as a model to study starch properties on biofuel yields holds signiWcant promise.

Dedicated Energy Crops and Crop Residues for Bioenergy Feedstocks in the Central and Eastern USA

“…Sweet sorghum has additional benefits of a typically shorter growing season and production of fermentable sugars, although biomass production is reduced compared to photoperiod sensitive sorghum [34,38]. In addition to the bmr gene, low amylose or waxy endosperm genes and sweet genes are being incorporated and evaluated in current breeding programs that would improve sorghum as a bioenergy feedstock [39].…”

Switchgrass for bioethanol and other value-added applications: A review

“…Hohenstein and Wright (1994) estimated a 95% reduction in soil erosion rates and a 90% reduction in pesticide use for herbaceous energy crops such as switchgrass relative to annual row crops like corn and soybean. While, the initial establishment of harvestable stands of switchgrass requires the use of high quality seed and herbicides for weed control, subsequent stand maintenance requires only limited and periodic herbicide applications (Sarath et al, 2008). Bransby et al (1998) stated that switchgrass could reduce CO 2 emissions and improve soil quality by carbon sequestration.…”

Categories of Resistance to Greenbug and Yellow Sugarcane Aphid (Hemiptera: Aphididae) in Three Tetraploid Switchgrass Populations

“…Switchgrass, Panicum virgatum L., a perennial warm-season grass native to the tallgrass prairie regions of North America, east of the Rocky Mountains, is being developed as a bioenergy crop for marginal soils in the USA [32,40]. It is a polyploid species, with a range of ploidies [7], however the tetraploid switchgrasses, which occur as upland or lowland ecotypes possess the best yield attributes [18,40,43].…”