abstract
Literature values for glucose release from corn stover are highly variable which would likely result in
tremendous variability in bio-refinery ethanol yield from corn stover feedstock. A relatively recent
change in United States corn genetics is the inclusion of the Bacillus thuringiensis (Bt) trait, which now
accounts for three-fourths of all US planted corn acreage. The objective of this study was to evaluate the
effect of corn grain yield, inclusion of the Bt trait, and location environment on corn stover quality for
subsequent ethanol conversion. Two hybrid pairs (each having a Bt and non-Bt near-isoline) were
analyzed giving a total of 4 hybrids. In 2010 and 2011, field plots were located in Michigan at four latitudinal
differing locations in four replicated plots at each location. Stover composition and enzymatic
digestibility was analyzed and estimated ethanol yield (g g1
) was calculated based on hydrolyzable
glucan and xylan levels. Analysis showed that there were no significant differences in total glucose or
xylose levels nor in enzymatically hydrolyzable glucan and xylan concentrations between Bt corn stover
and the non-Bt stover isolines. Regression analyses between corn grain yield (Mg ha1
) and corn stover
ethanol yield (g g1
) showed an inverse relationship indicative of a photosynthate source-sink relationship.
Nevertheless, the quantity of stover produced was found to be more critical than the quality of
stover produced in maximizing potential stover ethanol yield on a land area basis