WOUND HEALING AND DRY MATTER CONTENT OF ORANGEFLESHED SWEETPOTATO CULTIVARS AS INFLUENCED BY CURING METHODS

Abstract

Curing in sweetpotato is a crucial pre- or postharvest practice that could guarantee improved shelflife, but rarely practised by sweetpotato farmers in SubSaharan Africa, principally due to lack of knowledge. Wound healing ability of cultivars has been associated with good root storability. In this study, two orangefleshed sweetpotato cultivars (Apomuden and Nane) were either cured in-ground by dehaulming prior to harvest or field-piled over a seven-day period to study their responses to wound healing and changes in dry matter content. Apomuden is a low dry matter content (19%) variety in Ghana while Nane is a high dry matter content (27%) farmer cultivar under evaluation for formal release. A potato peeler was used to deliberately create the wounds on 21 storage roots. The curing treatment was applied and the subsequent post-treatment quality status of the storage roots was monitored daily over a seven-day period. Wound healing ability was scored as follows: 0 = no lignification, 0.5 = patchy lignification and 1= complete lignification. Wound healing ability score was not significantly different for Apomuden and Nane (0.83, 0.78, respectively; p = 0.120). However, storage roots cured by field-piled curing method resulted in significantly better wound healing ability than dehaulming (0.86, 0.75, respectively, p = 0.001). Over the seven-day curing period, Nane had a significantly higher and stable dry matter content compared with Apomuden (p = 0.008), whose dry matter content was lower and fluctuating. The field-piled curing resulted in higher (p = 0.020) dry matter content, 24%, compared with in-ground curing (22%). The fieldpiled curing method, which can easily be adopted by sweetpotato farmers, increased the dry matter content of the storage roots; therefore, it could potentially reduce the post-harvest losses in sweetpotato. The high dry matter content of Nane is a desirable root quality attribute for orange-fleshed cultivars and could augment existing cultivars in Ghana.