Evaluating Sweetpotato Varieties and Accessions in Hawai‘i

Abstract

Thirty sweetpotato (Ipomoea batatas var. batatas) genotypes were evaluated for yield, resistances to weevil or nematode pests, and consumer acceptance across three field trials planted at Pepe‘ekeo, Hawai‘i Island between 2017 to 2020. At harvest, storage roots were graded according to market standards, followed by scoring for damage by sweetpotato weevil (Cylas formicarius elegantulus), rough sweetpotato weevil (Blosyrus asellus), or nematodes; namely root-knot nematode (Meloidogyne spp.) or reniform nematode (Rotylenchus reniformis) in each market class. There were significant differences in marketable yields among accessions when data were analyzed statistically across all three field trials, as well as individually. ‘Regal’ (PI 566650) and ‘Sumor’ (PI 566657) were among the top three highest-yielding genotypes for Trials 1 and 2 (when no insecticides were applied to control weevils), and among the top six highest-yielding genotypes for the joint analysis across three trials. Significant differences among genotypes for combined sweetpotato weevil damage (incidence of sweetpotato weevil alone or incidence of both weevils together) were found in the joint analysis across three trials. ‘Regal’ was among the lowest seven genotypes for combined sweetpotato weevil damage, supporting earlier reports of its moderate resistance to this pest. In addition, two genotypes produced by the World Vegetable Center (Shanhua, Taiwan) (WT-320 and WT-108), were among the lowest genotypes for combined sweetpotato weevil damage, in agreement with earlier reports of their substantial resistance to this pest. Providing access to diverse germplasm will help farmers react to increasing pest pressure, while still allowing for high marketable yields. In addition, breeding and selection for pest resistance could be an important addition to integrated pest management of sweetpotato in Hawai‘i.