In order to form tubers of yam (Dioscorea opposita Thumb. cv. ‘Tanba’) in the air space of a culture box, plants were grown in solution culture. Results of experiment are as follows:
1) Compared with control of conventional soil production, about two times of tuber yields were obtained in solution culture.
2) The activities of α- and β-amylase of tuber grown in solution culture were lower than those of control. When tuber was grinded into “tororo, ” similar tendency was observed in the activity of polyphenol oxidase, since the browning reaction of solution cultured tuber was more slowly. These findings suggests that the yam tuber grown in solution culture is more suitable for food processing or cooking.