Comparison of specific gravity profiles inside tubers of potatoes

Samples of marketable potatoes of 15 cultivars harvested from breeding plots planted in 2000 and 2001 at the Benton Ridge Potato Breeding Substation in New Brunswick were used to compare the specific gravity distribution inside the potatoes. Computerized images of all individual potatoes were taken and used to measure their longitudinal and vertical axes and volumes. A slice about 15 mm thick was then cut through the center of a potato along the longitudinal axis. Six key positions were chosen on the slice, representing different tissue areas of the potato. A cube was cut out from each of the positions. The six cubes were scored for specific gravity. Regression analyses of specific gravity on positions of cubes were performed over samples of each of the cultivars. The regression equations represented the specific gravity profiles inside the cultivars. The profiles showed significant differences among the cultivars and thus were useful in assessing their table and processing qualities.