Maturing period of sweet potato cultivars estimated by the changes in quality of storage root

摘要

To estimate the maturation period of storage roots based on the quality of sweet potatoes, changes in quality of eight major Japanese cultivars were analysed during the growth period in 1988 and 1989. The storage roots of cv. Healthy Red, Koganesengan, Okinawa 100, and Beniazuma showed early bulking. The analysis of variance showed significant differences among cultivars and growth 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 growth periods were observed in these seven characters except for brix in steamed roots. At most harvest dates, palatability was significantly positively correlated with dry matter content (r>=0.8) and brix in steamed roots. At a few dates, palatability was significantly positively correlated with the brix and sucrose content in raw roots, but not with root yield, root size, and glucose content. Thus, maturation periods for quality can be estimated from changes in dry matter content. Based on increase in 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 Koganesengan into late-maturing type.