Inheritance of Resistance to Alfalfa Mosaic Virus in Soybean PI 153282

Alfalfa mosaic virus (AMV) infects soybean [Glycine max (L.) Merr.] causing mosaic or mottle patterns on leaves. Resistance to AMV has been identified in soybean, but no AMV resistance genes have been mapped or assigned gene symbols. The objective of this research was to study the genetic basis of resistance to AMV from plant introduction (PI) 153282. This resistance was studied in a population of F4:7 lines developed from a cross between this PI and the susceptible cultivar Syngenta (NK) S19-90. Results from the F4:7 population were confirmed in F2 and F2:3 populations developed by crossing the same parents. A major AMV resistance gene was mapped as a quantitative trait locus (QTL) near the simple sequence repeat marker Sat_226 in the F4:7 population. For this QTL, the resistance allele was from PI 153282, the LOD score was 45.5, and the QTL explained 79% of the genotypic variation for resistance in the population. The identification of an AMV resistance gene near Sat_228 was confirmed in the F2 and F2:3 populations and the resistance gene showed complete dominance in the F2 population. This AMV resistance gene identified from PI 153282 is named Rav1 and it should be useful in breeding for resistance to this virus.