Abstract
To estimate the maturing period of the storage root based on the quality of sweet potato, we analyzed the changes in quality of eight Japanese major cultivars during the growth period in 1988 and 1989. The storage roots of Healthy Red, Koganesengan, Okinawa 100, and Beniazuma showed early bulking. The analysis of variance showed significant differences among cultivars and growing period in root yield, root size, dry matter content, brix in raw and steamed roots, sucrose content in raw roots, glucose content in raw roots, and palatability. Significant interactions between cultivars and growing periods were observed in these seven characters except for brix in steamed roots. At most of the days of harvest, palatability was significantly and positively correlate with dry matter content (r≥0.8) and brix in steamed roots. At a few days of harvest, palatability was significantly and positively correlated with the brix and sucrose content in raw roots, but not with root yield, root size, and glucose content. Thus, maturing periods for quality may be estimated from the increasing pattern of dry matter content. Based on the increasing pattern of dry matter content, Healthy Red, Fusabeni, and Benikomachi were classified into early-maturing type, Beniaka, Okinawa 100, and Kokei 14 into medium-maturing type, and Beniazuma and Kognesengan into late-maturing type.
