Abstract
Length and width of tuberous roots in sweet potato were measured at intervals throughout the growing season. In this experiment, two cultivars Kokei 14 and Ayamurasaki, which have a spindle–and long–spindle–shaped tuberous root, respectively, were used. The number and length of tuberous roots were virtually determined within about 50 days after the planting, but individual values widely varied from 2 to 13 in number and from 5 to 30 cm in length. However, the width of tuberous roots kept increasing until the end of the growth period. Furthermore, lateral growth of tuberous roots closely related with the length of tuberous roots, i. e., the thickening rate was higher in the long tuberous root than in the short one. Therefore, the width/length ratios of tuberous roots, which widely varied among individuals at the early growth stage, gradually became uniform with the plant growth.
