Influence of Mother Seed Tuber Size on Yield and Incidence of Seedborne Potato Virus Y

Abstract Potato virus Y (PVY) is an important pathogen in seed potato production that may cause seed lots to be downgraded or rejected for certification. A study was conducted to determine if mother seed tuber size influences the prevalence of PVY within a seed sample during evaluations of seed-borne infection in a grow-out. The trial was conducted using Russet Norkotah (two growing seasons) and Umatilla Russet (one growing season). Several seed tuber size categories were utilized: (a) single drop (42 to 112 g), (b) small (113 to 169 g), (c) medium (170 to 282 g), (d) large (283 to 340 g), and (e) a mixed sample (year one only). The trial was planted in Kimberly, ID in a randomized block design. Visual evaluations for foliar PVY symptoms were conducted when plants were approximately 30 cm tall and total yield and yield profile evaluated at harvest. Visual foliar seedborne PVY incidence did not significantly differ among mother tuber size categories, for either year, cultivar, or seedborne PVY level. Seed tuber size treatments ranged from 38 to 43% visual PVY incidence in Umatilla Russet, 68 to 73% in Russet Norkotah in year one, and 5 to 6% in Russet Norkotah in year two. Differences in yield and yield size profile were observed, however, may be attributed to mother seed tuber size rather than PVY level. It appeared PVY was evenly distributed within seed samples and various mother tuber sizes and types did not affect the evaluation of seed-borne infection.