Abstract
In this study, the growth periodicity of Allium oreophilum ‘Zwanenburg’ plants grown outdoors was clarified. Simultaneously the effect of temperature on the initiation and development of flower buds was investigated. The inflorescences initiated in early September before planting. They formed tepals and stamens between early October and early December and bloomed in mid-May of the following year. After February, some plants that were moved from outdoors to a greenhouse kept at min. 10°C could flower in May. When bulbs were stored at 10, 15, 20, 25 or 30°C from August 13 to October 8, flower bud initiation occurred at 20 to 30 °C. Most of bulbs stored at 10 or 15°C formed new bulbs at the shoot apex instead of inflorescences. None of the bulbs developed inflorescence when they were grown in a greenhouse kept at min. 10°C. When bulbs were stored at 20, 25 or 30°C for 8 weeks from August 13 to October 8, followed by storage at 5 or 10°C for 8 weeks from October 8 to December 3, those stored at 10°C after 20, 25 or 30°C showed advanced flower bud development. However only bulbs stored at 5°C after 25 or 30°C could produce flowering inflorescences when they were grown in a greenhouse kept at min. 10°C.
