Reproduced from Crop Science. Published by Crop Science Society of America. All copyrights reserved. 262 WWW.CROPS.ORG CROP SCIENCE, VOL. 48, JANUARY– FEBRUARY 2008 RESEARCH S OYBEAN MOSAIC VIRUS (SMV) is one of the most destructive viral diseases in soybean [ Glycine max (L.) Merr.]. The use of genetic resistance is the most efective method of controlling this disease. Genetic resistance to SMV has been identi ied in various soybean cultivars, breeding lines, and plant introductions (PIs) (Cho and Goodman, 1982; Lim, 1985; Wang et al., 1998, 2005; Zheng et al., 2005). However, only a few soybean genotypes have been investigated for speci ic SMV resistance genes using inheri- tance study and allelism tests. Three independent loci, Rsv1, Rsv3, and Rsv4, conferring SMV resistance have been identi ied and mapped on diferent molecular linkage groups (MLG) of soybean (Hayes et al., 2000; Jeong et al., 2002; Yu et al., 1994). Nine alleles have been reported at the Rsv1 locus: Rsv1 (PI 96983), Rsv1-h (Suweon 97), Rsv1-k (Kwanggyo), Rsv1-m (Marshall), Rsv1-n (PI 507389), Rsv1-r (Raiden), Rsv1-s (LR1), Rsv1-t (Ogden), and Rsv1-y (York) (Chen and Choi, 2007). Rsv1 was mapped on the soybean MLG F (Yu et al., 1994); Rsv3 on MLG B2 (Jeong et al., 2002); and Rsv4 on MLG D1b (Hayes et al., 2000). Rsv1 was irst identi ied as a single allele (Kiihl and Hartwig, 1979) and later mapped on the MLG F; and two restriction frag- ment length polymorphism (RFLP) markers, pA 186 and pK 644a, A PCR-based Marker for the Rsv1 Locus Conferring Resistance to Soybean Mosaic Virus Ainong Shi, Pengyin Chen,* Cuiming Zheng, Anfu Hou, and Bo Zhang ABSTRACT Soybean mosaic virus (SMV) is a highly destruc- tive viral disease. Three loci with 12 alleles con- ferring SMV resistance have been identiied in soybean [Glycine max (L.) Merr.]. The objective of this study was to develop polymerase chain reaction–based markers for detecting the candi- date gene 3gG2 at the Rsv1 locus for SMV resis- tance in diverse soybean germplasm. A pair of DNA primers, Rsv1-f/r, was developed from the 3gG2 sequence. This primer pair produced a 341-bp DNA fragment speciic for soybean cul- tivars containing Rsv1 . The same fragment was conirmed in genotypes containing Rsv1 alleles including ‘Kwanggyo’ (Rsv1-k), ‘Marshall’ (Rsv1- m), ‘Ogden’ (Rsv1-t), PI 96983 (Rsv1), PI 507389 (Rsv1-n), ‘Raiden’ (Rsv1-r), and ‘Suweon 97’ (Rsv1-s). The Rsv1-f/r fragment was also ampli- ied in genotypes with two-gene combinations (Rsv1Rsv3 and Rsv1Rsv4) but not in genotypes containing only Rsv3 or Rsv4 or in the sus- ceptible genotypes. The primer pair was used to screen for Rsv1 alleles in 97 SMV resistant genotypes. Results showed that 55 genotypes contained the 3gG2 gene, while 17 genotypes carrying the Rsv1-y allele and additional 25 SMV-resistant genotypes carrying Rsv3 or Rsv4 were not ampliied a product using the 3gG2 primer pair. Analysis of an F 2 population derived from J05 (Rsv1Rsv3) × ‘Essex’ (rsv1rsv3) showed a cosegregation between the marker Rsv1-f/r and the Rsv1 allele. Rsv1-f/r was also shown to be linked to simple sequence repeat marker Satt114 on soybean molecular linkage group F with a distance of 5.42 cM. This marker will give breeders a tool for marker-assisted selection and gene pyramiding in soybean breeding for SMV resistance. Dep. of Crop, Soil, and Environmental Sciences, Univ. of Arkansas, Fayetteville, AR 72701. Received 10 Feb. 2007. *Corresponding author (pchen@uark.edu). Abbreviations: MAS, marker-assisted selection; MLG, molecular link- age group; PCR, polymerase chain reaction; PI, plant introduction; RAPD, random ampli icat ion of polymorphic DNA; RFLP, restriction fragment length polymorphism; SMV, Soybean mosaic virus; SSR, simple sequence repeat. Published in Crop Sci. 48:262–268 (2008). doi: 10.2135/cropsci2007.02.0076 © 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.