The 2010 ASHS Annual Conference

Enlarged or raised lenticel is a physiological disorder affecting potato (Solanum tuberosum L.) periderm and is known to be caused by high humidity conditions or oxygen depletion. The disorder starts off as white proliferated cells in waterlogged soils, with the lenticel eventually sinking or expanding in storage, leaving dark scars on the potato periderm. This greatly affects the marketability of fresh-market potatoes for growers, as skin quality is one of the important characteristics influencing tuber preference by consumers. Suberin deposition into the filling cells has also been linked to the shape of the lenticels. The goal of this research was to evaluate the effects of postharvest temperature/relative humidity (RH) on the development of raised lenticel disorder in fresh market potato tubers. Freshly harvested tubers, of the yellow-fleshed variety ‘Fabula', were stored at 13¢ªC or 20¢ªC, and low (60 to 70%) or high (85 to 95%) RH. Tubers were stored for 12 days (d) and evaluated each 3 d. Incidence and severity of raised lenticel disorder were rated according to the average size of the lenticels' diameter. The greatest weight loss occurred at 20¢ªC with low RH, losing an average of 2.6 ± 1.1% at 12 d. There was an effect of storage temp/RH on pulp moisture content (Pr > F = 0.0213), with 20¢ªC, low RH having the lowest pulp and peel moisture content of 79.6 ± 0.3% and 85.6 ± 1.3%, respectively, by the end of storage. Shriveling of the tubers was observed in those kept at the lower RH Although there was no significant difference in the incidence of the disorder in the four storage treatments, a higher mean lenticel size was observed on the tubers at the lower RH, at both 13 and 20¢ªC. Our preliminary results suggest that desiccation of the lenticel cells in storage increases the severity of the disorder. Results on effects of suberization on lenticel size will be presented. This information will provide growers and storage operators more knowledge on conditions that affect the incidence or severity of the disorder during storage.