A major quantitative trait locus for resistance to Potato leafroll virus is located in a resistance hotspot on potato chromosome XI and is tightly linked to N-gene-like markers

Potato leafroll virus (PLRV) causes one of the most widespread and importan t virus diseases in potato. Resistance to PLRV is controlled by genetic fac tors that limit plant infection by viruliferous aphids or virus multiplicat ion and accumulation. Quantitative trait locus (QTL) analysis of resistance to virus accumulation revealed one major and two minor QTL. The major QTL, PLRV.1, mapped to potato chromosome XI in a resistance hotspot containing several genes for qualitative and quantitative resistance to viruses and ot her potato pathogens. This QTL explained between 50 and 60% of the phenotyp ic variance. The two minor QTL mapped to chromosomes V and VI. Genes with s equence similarity to the tobacco N gene for resistance to Tobacco mosaic v irus were tightly linked to PLRV.1. The cDNA sequence of an N-like gene was used to develop the sequence characterized amplified region (SCAR) marker N127(1164) that can assist in the selection of potatoes with resistance to PLRV/