Research Plant Pathologist USDA ARS, Aberdeen ID Aberdeen, Idaho
Growing resistant potato varieties is one of the most effective options for controlling potato virus Y (PVY). Among the different types of PVY resistances, extreme resistance has been most effective in controlling PVY because plants with this kind of resistance do not get infected at all when exposed to all the known PVY strains. Potato variety Bistra is one such variety with potential for use as PVY resistant variety but previous attempts to characterize the PVY resistance genes responsible for the resistance have not provided consistent and conclusive results when tested using markers. This study was therefore conducted to confirm through classical graft inoculation if variety Bistra is indeed having PVY extreme resistance. Four potato varieties Bistra, Castle Russet, A98345-1 were graft inoculated on a PVY susceptible rootstock (Russet Burbank) infected with either of the three PVY strains (PVYO, PVYNTN and PVYN-Wilga) and leaf samples were tested in ELISA 21 days after inoculation. PVY was not detected in Bistra in all inoculations an indication of extreme resistance. Experiments on spray gun, rub inoculation and spreader row inoculation tests confirmed the results obtained in graft inoculation. Results from this study provided basis for identification of markers for characterization of varieties like Bistra and its subsequent utilization as parent for development of new improved PVY resistant varieties.
