Resistance to Potato virus Y in Potato

Growing potato cultivars resistant to Potato virus Y (PVY) offers the easiest and the most cost-effective solution to prevent the losses caused by PVY. Genes for resistance to PVY can be found in wild and cultivated potato species. Resistance genes functioning on the “gene-for-gene” basis are commonly used in breeding for resistance to PVY, because of their dominant and simple inheritance. Ten genes for resistance to PVY have been mapped to four potato genome segments on chromosomes IV, IX, XI and XII. Genes for hypersensitive resistance (HR) are usually PVY strain-specific, whereas the genes for extreme resistance (ER) are effective against a broad spectrum of PVY strains. The need for broad-spectrum resistance to PVY has been widely realized since the turn of the millennium when new PVY strains able to overcome strain-specific resistance to the common PVY strains became prevalent in potato crops worldwide. Field resistance to PVY is widely present in potato cultivars and based almost exclusively on minor genes contributing small effects. Marker-assisted selection provides an efficient approach for the selection of traits governed by major genes or quantitative trait loci (QTLs) with large effects. Genetically engineered resistance based on RNA silencing, the basal antiviral defense system of plants, is another option to protect potatoes against PVY.