Journal of Heredity 2004:95(4):322-326
© 2004 The American Genetic Association
Genetics of Resistance to Two Strains of Soybean Mosaic Virus in Differential Soybean Genotypes
From Medtronic Sofamor Danek, 1800 Pyramid Place, Memphis, TN 38132 (Ma); Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (Chen); Departments of Crop and Soil Environmental Sciences (Buss) and Plant Pathology, Physiology, and Weed Science (Tolin), Virginia Tech, Blacksburg, VA 24061-0404.
Address correspondence to Pengyin Chen at the address above, or e-mail: pchen{at}uark.edu.
There are seven pathotypes of soybean mosaic virus (SMV) representing seven strain groups (G1G7) in the United States. Soybean genotypes [Glycine max (L.) Merr.] may exhibit resistant (R), susceptible (S), or necrotic (N) reactions upon interacting with different SMV strains. This research was conducted to investigate whether reactions to two SMV strains are controlled by the same gene or by separate genes. Two SMV-resistant soybean lines, LR1 and LR2, were crossed with the susceptible cultivar Lee 68. LR1 contains a resistance gene Rsv1-s and is resistant to strains G1G4 and G7. LR2 contains the Rsv4 gene and is resistant to strains G1G7. Two hundred F2:3 lines from LR1 x Lee 68 and 262 F2:3 lines from LR2 x Lee 68 were screened for SMV reaction. Seeds from each F2 plant were randomly divided into two subsamples. A minimum of 20 seeds from each subsample were planted in the greenhouse and plants were inoculated with either G1 or G7. G1 is the least virulent, whereas G7 is the most virulent strain of SMV. The results showed that all the F2:3 lines from both crosses exhibited the same reaction to G1 and G7. No recombinants were found in all the progenies for reactions to G1 and G7 in either cross. The results indicate that reactions to both G1 and G7 are controlled by either the same gene or very closely linked genes. This research finding is valuable for studying the resistance mechanism and interactions of soybean genotypes and SMV strains and for breeding SMV resistance to multiple strains.