Suppression of Mother Tuber Enlargement in the Sweet Potato Cultivar “Koganesengan” by Transplantation of Bottled Tuber Seedlings

Abstract

Seed tubers of the sweet potato cultivar “Koganesengan” ranging from 40 to 70 g were cut in half at a right angle to the long axis. The half-cut tubers were planted in plastic wide-mouthed bottles, and the bottles were filled with a commercial soil mix. These bottled tubers were kept under natural sunlight in a glasshouse at 25°C, and watered regularly. After 3–4 wk, the bottled tuber seedlings were transplanted to a field, leaving the tubers in the plastic bottles. Mother tuber enlargement was suppressed in the bottle, but daughter tubers were formed above the bottle, and the mother tuber yield was 4.5% of the total fresh yield of mother and daughter tubers. In the cultivation of tuber seedlings without bottling, the mother tuber yield was 11.2% of the total yield.