Economic Performance of Potato Crops Dependent on Variety Specific Seed Piece Weight and Uniformity Within a Seed Lot

Abstract

Quality seed of the ideal size and type (i.e., whole-seed tubers or cut seed pieces) is critical in achieving uniform plant stands and optimal economic returns in commercial potato production. A survey assessed the performance of commercial seed cutting operations during 2021–22 to document the range of seed piece sizes planted in Washington. In addition, two field trials examined seed size performance (28, 42, 56, 70, 84, and 98 g (1.0, 1.5, 2.0, 2.5, 3.0, 3.5 oz)) for Clearwater Russet, Ranger Russet, and Russet Burbank. Seed type performance (whole vs cut) was also assessed for Clearwater Russet. As seed size increased from 28 to 98 g for all varieties and seed types, early plant growth generally improved, average tuber weight decreased by 22%, and stem and tuber number per plant increased by 77% and 50%, respectively. Cut Clearwater Russet seed produced 7% higher yields and 5% more economic return than whole seed. Economic return peaked for Clearwater Russet with a seed weight of 56 g (2.0 oz). Economic return of Ranger Russet and Russet Burbank peaked when seed size was between 70–84 g (2.5 to 3.0 oz) for Russet Burbank and at 84 g (3.0 oz) for Ranger Russet. Due to a highly variable range in cut seed size found in the commercial seed lot survey, growers may have lost an estimated $297 ha⁻¹ or $15,000 pivot⁻¹ (51 ha) during 2021–22 compared to a hypothetical potato field planted with uniform, economically optimal, seed sizes. We conclude that growers should target adequate seed sizes and minimize under- and oversized seed pieces to produce the highest economic return for each variety.