Mapping Quantitative Trait Loci for Long Coleoptile in Chinese Wheat Landrace Wangshuibai

Wheat (Triticum aestivum L.) cultivars with long coleoptiles can be sown deeply for better seedling establishment in drought environments. A population of 139 recombinant inbred lines (RILs) from a cross between a long-coleoptile Chinese landrace, Wangshuibai, and shortcoleoptile U.S. wheat cultivar, Wheaton, were characterized for coleoptile length and plant height. Heritabilities for coleoptile length were high (h2 > 0.82). Interval mapping identifi ed six signifi cant quantitative trait loci (QTL) on 1B, 3D, 4DS, 4DL, 5AS, and 5B for coleoptile length; four of them, on 3D, 4DS, 4DL, and 5AS, showed pleiotropic effects on plant height. One major QTL for long coleoptile was mapped on the locus Rht-D1 (Rht2) for reduced height (Rht) on chromosome 4DS and explained up to 65% of phenotypic variation for coleoptile length. Another major QTL was located on 4DL and explained up to 33% of phenotypic variation for coleoptile length. Standard height allele RhtD1a from Wangshuibai appeared to have an epistatic effect on the 4DL QTL for long coleoptile. Other QTL showed only a minor effect. Although Rht-D1a explained a major portion of genetic variation for long coleoptile in Wangshuibai, a combination of Rht-D1a in Wangshuibai with gibberellic acid (GA)–sensitive Rht genes for reduced wheat height from other sources should be able to select long coleoptiles, semidwarf cultivars in wheat breeding programs for which long coleoptile is a breeding objective. Jian-Bin Yu, Dep. of Agronomy, Kansas State Univ., Manhattan KS 66506; current address: Dep. of Forest Ecosystems and Society, Oregon State Univ., Corvallis, OR 97331. Gui-Hua Bai, USDA-ARS-PSERU, Kansas State Univ., Manhattan, KS 66506. Mention of trade names or commercial products in this article is solely for the purpose of providing specifi c information and does not imply recommendation or endorsement by the USDA. Contribution no. 09-226-J from the Kansas Agricultural Experiment Station. Received 6 Feb. 2009. *Corresponding author ([email protected]). Abbreviations: AFLP, amplifi ed fragment length polymorphism; CIM, composite interval mapping; GA, gibberellic acid; LOD, logarithm of odds; PCR, polymerase chain reaction; QTL, quantitative trait locus; RIL, recombinant inbred line; SIM, simple interval mapping; SSR, simple sequence repeat. Published in Crop Sci. 50:43–50 (2010). doi: 10.2135/cropsci2009.02.0065 © 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.