2494 WWW.CROPS.ORG CROP SCIENCE, VOL. 52, NOVEMBER– DECEMBER 2012 RESEARCH H ybrid breeding in wheat has tremendous potential to break the yield barrier and signi icantly enhance the yield stabil- ity especially in marginal environments. The basic requirements for hybrid wheat breeding such as positive values of better parent heterosis and economic hybrid seed production systems seem to be achievable at a commercial level (for review, see Longin et al., 2012; Volker Lein, unpublished data, 2012). Commercial hybrid wheat breeding is conducted in Europe, China, and India. Cur- rently, Europe is the main hybrid wheat growing region with acreage of around 160,000 ha in France and around 25,000 ha in Germany in 2010 (de Castelbajac, 2010). For hybrid wheat breeding, a large number of potential parental lines are available resulting in an enormous number of cross combinations for ield evaluation. To cope with the large Relevance of Speciic versus General Combining Ability in Winter Wheat Manje Gowda, C. Friedrich H. Longin, Volker Lein, and Jochen C. Reif* ABSTRACT Knowledge of quantitative genetic parameters is crucial in allocating resources for different steps of multistage selection programs. The main objective of the present study was to investigate the magnitude of variance of general combining ability (GCA) and speciic combining ability (SCA) effects and their interaction with environments in wheat (Triticum aestivum L.). We used four data sets (Exp. 1, 2, 3, and 4) generated in commercial hybrid winter wheat breeding programs with a total of 940 hybrids evaluated in multienvironment trials in 2010 and 2011 in France. In at least three out of four experiments, general combining ability variance for females (σ 2 GCA-F ), speciic combining ability variance (σ 2 SCA ), general combining ability of females × environment interaction variance (σ 2 GCA-F×E ), and general combining ability of males × times environment interaction variance (σ 2 GCA-M×E ) were signiicantly larger than zero but general combining ability variance for males (σ 2 GCA-M ) was signiicant only in Exp. 4. For Exp. 3, we found no signiicant difference between the best performing hybrid and the best performing commercial variety. In contrast, 1.8% of hybrids in Exp. 2 and more than 21% of the hybrids in Exp. 1 and 4 signiicantly (P < 0.05) outperformed the best commercial variety included in the respective experiment. This superiority was even apparent when projecting our indings on line varieties of the same cycle of selection. In Exp. 2, 3, and 4, general combining ability variance (σ 2 GCA ) was more pronounced compared to σ 2 SCA . Moreover, correlation between GCA predicted and observed hybrid performance was medium to high (r Exp.1  = 0.50, P < 0.01; r Exp.2 = 0.90, P < 0.01; r Exp.3 = 0.59, P < 0.01; and r Exp.4 = 0.92, P < 0.01). Consequently, selection based on GCA effects is promising in hybrid wheat breeding program. M. Gowda, C.F.H. Longin, and J.C. Reif, State Plant Breeding Institute, Univ. of Hohenheim, 70593 Stuttgart, Germany. V. Lein, Saaten Union Recherche SAS, 163 Avenue de Flandre, F-60190 Estrées-Saint-Denis, France. Received 19 Apr. 2012. *Corresponding author (Jochen.Reif@ uni-hohenheim.de). Abbreviations: σ 2 e , residual variance confounded with speci ic combining ability × environment interaction variance; σ 2 GCA , general combining ability variance; σ 2 GCA×E , general combining ability × environment interaction variance; σ 2 GCA-F , general combining ability variance for females; σ 2 GCA-F×E , general combining ability of females × environment interaction variance; σ 2 GCA-M , general combining ability variance for males; σ 2 GCA-M×E , general combining ability of males × environment interaction variance; σ 2 SCA , speci ic combining ability variance; CH, commercial heterosis; CHA, chemical hybridizing agent; GCA, general combining ability; H 2 , broad-sense heritability; SCA, speci ic combining ability. Published in Crop Sci. 52:2494–2500 (2012). doi: 10.2135/cropsci2012.04.0245 © Crop Science Society of America | 5585 Guilford 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.