Finding the sweet spot with sweetpotato varieties

Not all scientific research is done in a sterile lab setting or in carefully planted test plots. Some of it is done on plates, with forks and knives.

A group from Washington State University Extension – Laura Schulz, Jordan White and Carol Miles – shared their results from a study titled “Finding the Sweet Spot: Evaluating 21 Sweetpotato Entries with a Public Taste Test” at the most recent American Society for Horticultural Science conference.

The group started by testing 28 different sweetpotato cultivars, evaluating them in field trials from 2019-2025 for both yield and wireworm resistance. But flavor and eating quality are also essential traits for the marketability of new varieties.

After the field trials, a public taste test of 21 sweetpotato cultivars took place in February 2025. The tubers were all prepared the same way – wrapped in aluminum foil, then baked at 375º until they were soft, with no seasonings. After they cooled, they were cubed for the samplers.

The named cultivars noshed upon were ‘Monaco,’ ‘Covington,’ ‘Purple,’ ‘Bayou Belle,’ ‘Orleans,’ ‘Cascade,’ ‘Sakura,’ ‘Beauregard’ and ‘Molokai Purple.’ Those without official names yet included ‘USDA-16-031,’ ‘USDA16-051,’ ‘USDA-04-791,’ ‘USDA-04-284,’ ‘USDA-04-136,’ ‘USDA-23-039,’ ‘USDA-19-036,’ ‘18-161P,’ ‘USDA-17090,’ ‘18-115P,’ ‘21-180P’ and ‘19-59P.’

The taste test participants were Washington State University employees, local farmers, gardeners, chefs and produce buyers. Each participant rated more than 12 entries – and each entry was evaluated by 31 individuals on average.

The taste testers ranked sweetness, texture, firmness, flavor, color and overall acceptability, from 1 (very poor) to 5 (very good).

The highest rated overall, across all categories, were ‘Monaco’ (3.9), ‘USDA-16-031’ (3.9) and ‘Covington’ (3.8). Covington, as the control in the test, had high overall acceptability, sweetness, flavor and color, but moderate texture and low firmness.

Purple sweetpotato entries rated high in color (averaging 4.2) but low overall acceptability (just 2.4). ‘Sakura’ was the highest ranked purple cultivar with a 3.2. While the purple color is highly attractive, the roots need improved yield and eating quality, according to the research team.

‘Cascade’ (a USDA-WSU 2023 release that’s wireworm- resistant) had moderate overall acceptability (3.2), sweetness (3.5), flavor (3.4) and texture (3.2) but low firmness and color.

Based on what this project found, the WSU Extension team recommends ‘USDA-16-051’ and ‘USDA-04-791’ for public release. They have shown high eating quality as well as good yield results.

by Courtney Llewellyn