Abstract
Potato (Solanum tuberosum L.) is prone to infection by viral pathogens due to successive cycles of vegetative propagation. Potato virus Y (PVY) is an economically important virus and has recombinant strains that may affect potato yield and quality differently. In a two year study, four varieties, Alturas, Russet Burbank, Ranger Russet, and Umatilla Russet, were grown in a screen-house to prevent in-season spread and mixing of PVY strains among plants. Leaves were inoculated manually with PVYNTN, PVYN-Wi and PVYO when plants were 20-25 cm in height. Tubers from each plant were harvested, stored at 8.9° C and evaluated for external and internal PVY symptoms at harvest and after 5 and 10 months in storage. Observed tuber symptoms included: external rings, internal rings, internal spots and necrosis under the skin. The center plank from each tuber was fried at 191° C for 3.5 minutes and reflectance and fry quality measured. Tuber samples were assayed for the presence of specific PVY strains using ELISA and RT-PCR. In year one, none of the varieties infected with PVYN-Wi showed symptoms at harvest or throughout storage, except tubers of Alturas which had 41% incidence after 10 months in storage. All varieties exhibited symptoms, except Russet Burbank tubers did not exhibit any symptoms at harvest when infected with PVYO. In year two, none of the varieties showed symptoms when infected with PVYO at harvest or throughout storage. Fry quality was not diminished with PVYNTN and PVYN-Wi, which was not the case with PVYO. PVY had limited effect on fry quality unless raw tuber symptoms were present. Results from these evaluations will help identify the potential risk of a specific variety having tuber quality degradation if infected with a specific PVY strain.