Seed-piece Spacing Influences Yield, Size Distribution, Net Returns, and Stem and Tuber Density of Three Processing Potato Cultivars

Abstract

Seed-piece spacing is an important economic consideration in the production of potatoes and optimum varies by cultivar and intended market. A study was designed to determine the influence of seed-piece spacing on yield, tuber size distribution, net returns and stem and tuber density of three processing potato cultivars. Seed tubers of cvs. Russet Burbank, Frontier Russet and Ranger Russet were planted 8, 15, 23, 31, 46, 61, 76, or 91 cm apart at two locations in 1988 and 1989. Total, marketable (U.S. No. 1), and mid-size (226–452 g tubers) yield, yield of five incremental size categories, net profits from a typical processing contract, and stem and tuber density (number per m of row) were determined. All three cultivars achieved highest total yields at the narrowest (8 cm) spacing. Marketable and mid-size yield were optimized between 15 and 31 cm depending on the cultivar. The size distribution of tubers shifted from a predominance of small tubers at the narrow spacing treatments to a predominance of large tubers at the wide spacing treatments. The rate of shift across spacing treatments was cultivar dependent. Russet Burbank showed a bimodal response to spacing for net returns with optimums at the 23- and 46-cm spacing treatments. Frontier Russet and Ranger Russet showed optimums at 23 cm. All three cultivars gave maximum mid-size yields at a stem density of 10.5–12.1 per m of row and a tuber density of 23.9–24.9 per m of row.