Use of an Advanced Intercross Line Population for Precise Mapping of Quantitative Trait Loci for Gray Leaf Spot Resistance in Maize

Gray leaf spot [GLS, causal agent Cercospora zeae-maydis (Tehon and E. Y. Daniels)] is an important fungal disease of maize in the U.S. and worldwide. The IBM population, an advanced intercross recombinant inbred line population derived from a cross between the maize lines Mo17 (resistant) and B73 (susceptible), was evaluated in three environments (Andrews, NC in 2005, 2006, and 2007) for resistance to GLS and for days from planting to anthesis (DTA). A conventional recombinant inbred line population derived from the same two parents (the “Stuber” population) was also assessed for GLS resistance in two environments (Andrews NC, 2004 and 2005). Quantitative trait loci (QTL) for GLS resistance were detected in each population. Five signifi cant QTL were detected in the IBM population in bins 1.05, 2.04, 4.05, 9.03, and 9.05. In each case the QTL were localized to regions less than 3 centiMorgans (cM). Two QTL for GLS resistance were identifi ed in the Stuber population in bins 2.04 and 7.05. The GLS QTL in bin 2.04 was previously identifi ed as a QTL for southern leaf blight resistance in the IBM population. These results were compared with results from fi ve previous GLS QTL studies and two potential GLS QTL “hotspots” were identifi ed in bins 1.05–1.06 and 2.03–2.05. As expected, QTL were identifi ed with much more precision in the IBM population compared to the Stuber population and to previous studies. There was no signifi cant correlation between disease resistance and days to anthesis. Three DTA QTL were detected in bins 4.09, 8.05, and 9.02, which did not co-localize with GLS QTL. P.J. Balint-Kurti, USDA-ARS, Plant Science Research Unit and Dep. of Plant Pathology, North Carolina State Univ., Raleigh, NC 27695-7616; R. Wisser and J.C. Zwonitzer, Dep. of Plant Pathology, North Carolina State Univ., Raleigh, NC 27695-7616. Received 14 Dec. 2007. *Corresponding author ([email protected]). Abbreviations: AIL, advanced intercross line; AUDPC, area under disease progress curve; BLUP, best linear unbiased predictor; cM, centiMorgan; DTA, Days to anthesis; GLS, gray leaf spot; IBM, intermated B73/Mo17; Imu, IBM map units; MQM, Multiple QTL mapping; QTL, quantitative trait loci; RIL, recombinant inbred line; WMD, weighted mean disease. Published in Crop Sci. 48:1696–1704 (2008). doi: 10.2135/cropsci2007.12.0679 © 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. Published September, 2008