Tuesday, November 6, 2007 - 11:30 AM
162-8
Designing Bioenergy Crops of the Future.
Finite oil supplies, an uncertain political climate in many oil-exporting countries, increasing oil prices, and a desire to curb greenhouse gas emissions are driving up the demand for alternative fuels, with a goal set by the DOE to replace 30% of gasoline with fuel from renewable resources by 2030. This will only be feasible by producing dedicated bioenergy crops. In the US the overall production of biomass may need to increase as much as seven-fold. The precise increase depends in part on improvements in biomass conversion efficiency, through a combination of optimized processing technology and enhanced germplasm. It is likely that a variety of different bioenergy crops will serve as feedstocks for alternative fuels, the choice depending on the climate, soil, crop rotation schedule, compatibility with existing practice or incentives to retool. Enhancing germplasm for fuel production will require a different selection strategy than is common for most crops today. Main traits to focus on are biomass yield, biomass conversion efficiency, and root structure. Biomass yield is dictated by plant height, stem diameter, degree of tillering, and can be enhanced by hybrid vigor and delaying the transition to reproductive development. Biomass conversion efficiency depends largely on cell wall composition and architecture. Cell wall biogenesis is a complex process with considerable differences among species. Cell wall composition also affects important agronomic traits such as standability, drought tolerance, disease and pest resistance, which in turn affect biomass yield. Roots are important contributors to soil organic matter content and can compensate for reduced availability of organic matter resulting from the harvest of vegetative residues. Root architecture is also important for water and mineral uptake, especially critical on marginal lands. The increasing availability of genome sequences and the development of high-throughput analytical tools offer tremendous opportunities to expedite the development of dedicated bioenergy crops.
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