The Virgin A Mutant was resistant to the tobacco vein-mottling virus. Resistance was controlled by a single genetic factor and was recessive in the sense that a homozygous genotype was necessary to obtain plants completely free of symptoms. Rating of infected plants indicated that the heterozygote was intermediate and the gene action was completely additive. In a second study, differences among burley cultivars for tolerance to TVMV were influenced by both additive and nonadditive genetic factors.