Location: Plant Science ResearchTitle: Quantitative Trait Loci and Trait Correlations for Maize Stover Cell Wall Composition and Glucose Release for Cellulosic Ethanol Author
|Jung, Hans Joachim|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2009
Publication Date: 3/1/2010
Publication URL: http://hdl.handle.net/10113/46385
Citation: Lorenzana, R.E., Friskop-Lewis, M., Jung, H.G., Bernardo, R. 2010. Quantitative Trait Loci and Trait Correlations for Maize Stover Cell Wall Composition and Glucose Release for Cellulosic Ethanol. Crop Science. 50(2):541-553. Interpretive Summary: A national goal has been set of replacing 30% of our oil use with biofuels by 2030. A billion tons of biomass feedstocks will be required to meet this goal, and corn stover is expected to supply 20% of the total biomass. Yields of ethanol from corn stover could be increased if the stover had characteristics that favored more efficient conversion to ethanol. A study was conducted with genetic lines derived from intermating the two most important parents of commercial corn hybrids to determine if genetic markers could be identified for traits important to cellulosic ethanol production from corn stover. Genetic markers were identified for higher levels of the cellulosic sugars in stover, lower amounts of the inhibitory compound known as lignin, and increased efficiency of sugar release by the cellulosic ethanol conversion process. Associations among the traits indicated that simultaneous selection for corn grain yield and stover cellulosic ethanol potential should be possible. These data will be of interest to seed companies because the results indicate that using marker-assisted selection to breed for improved corn stover quality should be effective.
Technical Abstract: In cellulosic ethanol production, the efficiency of converting maize (Zea mays L.) stover into fermentable sugars partly depends on the stover cell wall structure. Breeding for improved stover quality for cellulosic ethanol may benefit from the use of molecular markers. However, limited quantitative trait loci (QTL) studies have been published for maize stover cell wall components, and no QTL study has been published for glucose release from stover by a cellulosic ethanol conversion process. The objectives of this study were to examine the relationships among stover cell wall components and glucose release and to identify QTL with major effects, if any, influencing stover cell wall composition and glucose release. Testcrosses of 223 intermated B73 x Mo17 recombinant inbreds and the parent lines were analyzed for cell wall composition and glucose release after acid pretreatment and enzymatic hydrolysis. As expected, glucose, xylose, and Klason lignin comprised the bulk (~72%) of the stover dry matter. Significant genetic variance and moderate heritability were observed for all traits. Genetic and phenotypic correlations among traits were generally favorable but also reflected the complexity of maize stover cell wall composition. We found 152 QTL, mostly with small effects, for glucose release and cell wall components on both a dry matter and cell wall basis. Because no major QTL were found, methods that increase the frequency of favorable QTL alleles or predict performance based on markers, such as marker-assisted recurrent selection or genome-wide selection, would be appropriate in marker-assisted breeding for maize stover quality for cellulosic ethanol.