Abstract
This research was carried out from 1955 to 1959 to study the influence of storage temperature for onion bulbs on the dates of bolting and flowering and the yield of seeds at Tsuruoka, Yamagata Prefecture.
Storing mother bulbs at 20°C or above (especially above 30°C) delayed bolting and flowering and reduced the yield of seeds. In Sappro-ki variety, in which flower buds were differentiated in fall, storage at 30°C affected adversely the development of flower buds, making the inflorescence deformed and sterile.
Cold storage at 0-5°C also caused later bolting and smaller yield of seeds than the storage at moderate temperature.
Storage at about 10°C accelerated development of flower buds in the stored bulbs, leading to earlier bolting than at higher or lower temperature.
The date of bolting was influenced so markedly by the date of melting of snow cover and the growing conditions in spring, that storage temperature of bulbs had relatively little effect on the date of bolting as compared with climatic conditions.
Based on the above mentioned results, the favorable temperature for storing onion bulbs for seed production was discussed.
