Sources and Effectiveness of Potato PVY Resistance in IHAR’s Breeding Research

Abstract

Resistance to Potato virus Y (PVY) is one of the most important traits in seed and ware potato production. Currently the tobacco-necrosis inducing PVYN strain including PVYN-Wi and PVYNTN dominates in the PVY population in Poland. The PVYO strain which dominated in early 1980s is rarely detected. Since early 1950s, breeding for PVY resistance in IHAR was a part of the program developing parental lines, which resulted in selecting lines extremely resistant to PVY. The selection of these lines was improved by the application of developed molecular markers. Moreover, the group of genes conferring comprehensive hypersensitive resistance (HR) to all strains of PVY was identified and mapped. The cultivars obtained from parental lines have enhanced level of resistance to PVY. For registered cultivars, the level of resistance to PVY is monitored in field exposure tests, while the reaction to four different isolates of PVY is examined by artificial inoculations. The 36 cultivars with field resistance scores 7.5 and 9 expressed resistance to all tested isolates and 23 of them originated from IHAR parental lines. Several moderately resistant cultivars varied in sensitivity to the PVY isolates and in majority they were more sensitive to isolates Wi (collected in 1984) and 12/94 (collected in 1994), than to older isolates LW and Ny collected in 1970-ties.