Sources of resistance to viruses in the Potyviridae.

Resistance to 56 viruses in the family Potyviridae in 334 plant species was tabulated. Studies conducted in the last 60 years have elucidated the genetics and usefulness of 135 resistance genes, but no reports on the heritability of other sources of resistance are available. In most of the plant species, resistance to species of Potyviridae was simply inherited, either dominantly (60 genes) or recessively (39 genes). In some cases resistance was conferred by two or more genes. Symbols have been assigned to 86 genes, of which very few are duplicate entities. Resistance genes can be useful in determining relationships among these viruses, as well as for their identification. The role of conventional breeding and biotechnology in transferring genes from one species to another is discussed.