Tuesday, November 14, 2006

Characterization and Analysis of Maize Traits Beneficial to the Lignocellulosic Ethanol Industry.

Aaron Lorenz and James Coors. University of Wisconsin-Madison, 1575 Linden Dr., Madison, WI 53706

The UW corn breeding project conducted a field evaluation of 50 hybrids in 2005. The germplasm in this trial spans a large range of stover composition. Furthermore, there are several gene mutations of particular interest for energy/biomass utilization that may impact the economics of cellulosic ethanol production. For example, the brown-midrib1-4 (bm1, bm2, bm3, bm4) mutations reduce lignin concentrations by up to 50%, and the Leafy mutant adds up to six or more leaves above the ear and thereby significantly increases stover dry matter production.  Stover and grain yield measurements were taken at physiological maturity.  Stover samples were taken from each plot, ground, and scanned using a near infrared reflectance spectrophotometer (NIRS).  NIRS scans were sent to the National Renewable Energy Laboratory (Golden, CO) for prediction of stover composition and theoretical ethanol potential (TEP, L Mg-1).  Stover fermentability was indirectly measured using an in vitro ruminal fermentation test.  In addition, the forage quality traits neutral detergent fiber (NDF) and acid detergent fiber (ADF) were estimated.  Theoretical ethanol yield ranged from 2613 L ha-1 to 4482 L ha-1.  The inbreds developed at Wisconsin for silage yield and quality (W601S – W604S) appear to have compositional properties favorable for cellulosic ethanol production as shown by stover yield, TEP, and fermentability.  Stover yield was more variable than stover compostion among the entries included in this experiment.  TEP was unrelated to fermentability suggesting that the quality of a feedstock for cellulosic ethanol production may be more dependent on carbohydrate digestibility rather than carbohydrate quantity.  Generally, no correlations between stover traits and grain yield were found in this study.