Quantitative Trait Loci and Trait Correlations for Maize Stover Cell Wall Composition and Glucose Release for Cellulosic Ethanol

In cellulosic ethanol production, the effi ciency 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 benefi t 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 (GLCRel) from stover by a cellulosic ethanol conversion process. Our objectives were to characterize the relationships among stover cell wall components and GLCRel, and to identify QTL with major effects, if any, infl uencing stover cell wall composition and GLCRel. Testcrosses of 223 intermated B73 × Mo17 recombinant inbreds and the parent lines were analyzed for cell wall composition and GLCRel after acid pretreatment and enzymatic hydrolysis. As expected, glucose (GLC), xylose (XYL), and Klason lignin (KL) composed the bulk (~72%) of the stover dry matter. Signifi cant genetic variance and moderate heritability were observed for all traits. Genetic and phenotypic correlations among traits were generally in the favorable direction but also refl ected the complexity of maize stover cell wall composition. We found 152 QTL, mostly with small effects, for GLCRel 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 that predict performance based on markers would be appropriate in marker-assisted breeding for maize stover quality for cellulosic ethanol. R.E. Lorenzana, M. Friskop Lewis, H.-J.G. Jung, and R. Bernardo, Dep. of Agronomy and Plant Genetics, Univ. of Minnesota; H.-J.G. Jung, USDAARS, 411 Borlaug Hall, 1991 Upper Buford Cir., St. Paul, MN 55108. Mention of a proprietary product does not constitute a recommendation or warranty of the product by the University of Minnesota or the USDAARS and does not imply approval to the exclusion of other suitable products. Received 9 Apr. 2009. *Corresponding author ([email protected]). Abbreviations: ARA, arabinose; CW, cell wall; FA, ferulate esters; FDR, false discovery rate; GAL, galactose; GLC, glucose; GLCRel, glucose release; KL, Klason lignin; LOD, logarithm of the odds; LR, likelihood ratio; MAN, mannose; NDF, neutral detergent fi ber; NIRS, near infrared refl ectance spectroscopy; PCA, p-coumarate esters; QTL, quantitative trait loci; UA, uronic acids; XYL, xylose. Published in Crop Sci. 50:541–555 (2010). doi: 10.2135/cropsci2009.04.0182 Published online 22 Jan. 2010. © Crop Science Society of America | 677 S. Segoe Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.