1996 Volume 65 Issue 2 Pages 373-380
The growth periodicity of Allium unifolium plants grown in an unheated plastichouse was assessed while simultaneously investigating the effect of temperatureon the initia-tion and development of flower buds.
In bulbs grown in an unheated plastic house, the first inflorescences were initiated in mid-November. They formed tepals and stamens in mid-January of the following year and bloomed from early to mid-April. Two weeks later, the 2nd and 3rd inflorescences were initiated in axillary buds and bloomed in mid- to late April.
When bulbs, which were planted in early October were grown in an unheated plastic house or a greenhouse kept above 10°C, they flowered satisfactorily. However, those grown in a greenhouse kept above 20°C had fewer flowered and shorter scapes.
When bulbs were stored at 9°, 15°, 20°, 25° or 30°C from 1 August to 1 October, flower bud initiation occurred at 9° to 20°C, but the optimum range was 9°-15°C. Bulbs stored at 9°C bloomed earlier, but had fewer inflorescences when they were grown in a greenhouse kept above 10°C.
Flower buds of bulbs stored at 10°C for 3 months were the earliest to differentiate; they flowered in mid-January if the greenhouse was kept above 10°C.
Bulbs harvested from plants grown in an unheated plastic house in the previous season flowered 1 month earlier than did those harvested from plants grown outdoors, when they were stored at 10°C for 3 months (early July to October) and grown at or above 10°C.