Genome‐wide Association Mapping of Fusarium Head Blight Resistance and Agromorphological Traits in Barley Landraces from Ethiopia and Eritrea

Fusarium head blight (FHB), caused primarily by Fusarium graminearum, is an important disease of barley (Hordeum vulgare L.), and other cereals. In barley, the genetic basis of FHB resistance has been intensively studied through linkage mapping that identified several quantitative trait loci (QTL). However, our understanding and application of these QTL in breeding is still limited due to the complex nature and low-to-moderate heritability of FHB resistance. previous studies used either breeding lines, unimproved varieties, or germplasm selections. Here, we used association mapping in barley landraces to identify QTL associated with FHB severity, deoxynivalenol (DoN) concentration and correlated agromorphological traits. Diverse barley landraces (n = 298) from Ethiopia and Eritrea were evaluated for the traits under field conditions for 2 yr (2011–2012) in Crookston, MN, and genotyped with 7842 single nucleotide polymorphism (SNp) markers. Association mapping analysis using a mixed model corrected for pairwise relatedness between individuals identified one common resistance QTL on barley chromosome 2HL significantly associated with both FHB severity and DoN concentration and another one on 4HL associated with DoN concentration. The QTL identified on 2HL is associated with the row-type locus Vrs1. Both of these QTL were not significantly associated with heading date or plant height unlike other QTL reported in previous studies. Thus, the resistant accessions carrying these QTL may be used in breeding programs without the confounding effects from these agromorphological traits. Importantly, these QTL could be new alleles preserved in this unique germplasm, and the linked SNp markers found may be useful in marker-assisted introgression of resistance. Dep. of Plant Pathology, Univ. of Minnesota, St. Paul, MN 551086030. Bullo Erena Mamo, current address: Dep. of Plant Pathology, Univ. of California, Davis, CA 95616-5270. Received 15 June 2014. Accepted 16 Jan. 2015. *Corresponding author (bsteffen@umn.edu). Abbreviations: BLAST, basic local alignment search tool: BLUP, best linear unbiased predictions: DON, deoxynivalenol: DTH, days to heading: EEBC, Ethiopian and Eritrean Barley Collection: EL, exsertion length: EMMA, efficient mixed model association: FDR, false discovery rate; FHB, Fusarium head blight: GWAS, genome-wide association study: KD, kernel density: LD, linkage disequilibrium: MAF, minor allele frequency: MLM, mixed linear model: NSGC, National Small Grains Collection: PCA, principal component analysis: PH, plant height: QTL, quantitative trait loci: RT, row-type morphology: SA, spike angle: SNP, single nucleotide polymorphism: VIR, N. I. Vavilov Research Institute of Plant Industry: vrs1, six-rowed spike 1: vrs2, six-rowed spike 2. Published in Crop Sci. 55:1494–1512 (2015). doi: 10.2135/cropsci2014.06. 0428 Freely available online through the author-supported open-access option. © 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. Published August 10, 2015