Identifi cation of Quantitative Trait Loci Associated with Fructose, Glucose, and Sucrose Concentration in Snap Bean Pods

Sugars, including fructose, glucose, and sucrose, contribute signifi cantly to the fl avor and consumer acceptance of snap beans (Phaseolus vulgaris L.). Differences between dry and snap bean cultivars and among snap bean cultivars in the patterns of accumulation of sugars have been observed. In ‘Eagle’, a white-seeded, largesieve snap bean cultivar, fructose and glucose concentrations in developing pods decreased while sucrose concentration increased with increasing pod size. In contrast, fructose and glucose concentrations increased while sucrose remained unchanged with increasing pod size in Puebla 152, a black-seeded dry bean landrace from Mexico. A population derived from the cross Eagle × Puebla 152 consisting of 75 F9:10 recombinant inbred lines (RILs) was developed by single seed descent. Signifi cant differences in fructose, glucose, and sucrose concentrations of sieve size 4 (8.33–9.52 mm) pods were observed among RILs. No signifi cant genotype × year interactions were observed. Heritability estimates for fructose, glucose, and sucrose were 0.85 ± 0.16, 0.81 ± 0.16, and 0.85 ± 0.16, respectively. A single quantitative trait locus (QTL) on linkage group B1 was identifi ed that is closely linked to random amplifi ed polymorphic DNA (RAPD) marker W9.1050 and explains 28.8 and 26.6% of the variation in pod fructose and sucrose concentration, respectively. A two-QTL model, including W9.1050 and RAPD marker F8.500 on linkage group B6, explained 36.4% of the variation in glucose concentration in pods. K.M. VandenLangenberg and J. Nienhuis, Department of Horticulture, University of Wisconsin–Madison; P.C. Bethke. Department of Horticulture, University of Wisconsin–Madison and USDA ARS, Vegetable Crops Research Unit, Madison, WI. Received 30 July 2011. *Corresponding author ([email protected]). Abbreviations: EP-RIL, Eagle × Puebla 152 recombinant inbred line; HPLC, high-performance liquid chromatography; LOD, logarithm to the base 10 of the likelihood odds ratio; LSMEAN, least square mean; pLOD, penalized logarithm to the base 10 of the likelihood odds ratio; QTL, quantitative trait loci/locus; RAPD, random amplifi ed polymorphic DNA; RIL, recombinant inbred line. Published in Crop Sci. 52:1593–1599 (2012). doi: 10.2135/cropsci2011.07.0396 © 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.