Detection and Confirmation of Quantitative Trait Loci for Soybean Seed Isoflavones

Interest in soybean [Glycine max (L.) Merr.] isoflavones has increased in recent years owing to numerous reported health benefits. Consequently, quantitative trait loci (QTL) detection for marker-assisted breeding for isoflavones is being examined for genetic gains. This study sought to detect QTL for soybean isoflavones in a population of 274 recombinant inbred lines derived from a cross between ‘Essex’ and ‘Williams 82’ that were subdivided and tested by maturity (early, mid, and late). The field tests were conducted in three environments in 2009 (Knoxville, TN; Harrisburg, IL; and Stuttgart, Ar). The population was genotyped with 480 polymorphic single nucleotide polymorphism markers. Isoflavones for each replicate were analyzed by near infrared reflectance spectroscopy, whose prediction equation was based on high performance liquid chromatography. Each maturity test, containing 91 or 92 recombinant inbred lines, was analyzed separately for QTL. In total, 21 QTL were detected: 7 for genistein (chromosomes 5, 6, 9, 13, 17, and 19), 5 for daidzein (chromosomes 5, 6, 9, 13, and 19), 3 for glycitein (chromosomes 6, 9, and 20), and 6 for total isoflavone content (chromosomes 5, 6, 9, 13, and 19). of these 21 QTL, 12 were confirmed or positional confirmations from other studies. Utilization of these QTL could potentially lead to marker-assisted selection approaches for genetic gains in improving soybean isoflavones. C.J. Smallwood, D.A. Kopsell, C.E. Sams, D.R. West, and V.R. Pantalone, Dep. of Plant Sciences, Univ. of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996; C.N. Nyinyi, Monsanto, 140 W. Industrial Drive, Harrisburg, SD 57032; P. Chen, Dep. of Crop, Soil, and Environmental Sciences, 115 Plant Science Building, Univ. of Arkansas, Fayetteville, AR 72701; S.K. Kantartzi, Dep. of Plant, Soil and Ag. Systems, Southern Illinois Univ., Carbondale, IL 62901; P.B. Cregan and D.L. Hyten, USDA, ARS, Soybean Genomics and Improvement Lab, Beltsville, MD 20705; D.L. Hyten, present address: Dupont Pioneer, 8305 NW 62nd Ave., PO Box 7060, Johnston, IA 50131. Received 23 May 2013. *Corresponding author (csmallw1@utk.edu). Abbreviations: CIM, composite interval mapping; E, environment; ETREC, East Tennessee Research and Education Center; G, genotype; HPLC, high performance liquid chromatography; LOD, logarithm of odds; LSMEAN, least squares mean; MAS, marker-assisted selection; Mbp, mega base pair; NIRS, near-infrared reflectance spectroscopy; QTL, quantitative trait loci; RIL, recombinant inbred line; SNP, single nucleotide polymorphism; ST, stem termination. Published in Crop Sci. 54:595–606 (2014). doi: 10.2135/cropsci2013.05.0340 © 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.