EFFECTS OF TEMPERATURE ON THE GROWTH AND FLOWERING OF ALLIUM-UNIFOLIUM KELLOGG

The growth periodicity of Allium unifolium plants grown in an unheated plastic house was assessed while simultaneously investigating the eff ect of temperature on the initiation and development of flower buds. I n bulbs grown in an unheated plastic house, the first inflorescences w ere initiated in mid-November. They formed tepals and stamens in mid-J anuary 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 plante d in early October were grown in an unheated plastic house or a greenh ouse kept above 10 degrees C, they flowered satisfactorily. However, t hose grown in a greenhouse kept above 20 degrees C had fewer flowered and shorter scapes. When bulbs were stored at 9 degrees, 15 degrees, 2 0 degrees, 25 degrees or 30 degrees C from 1 August to 1 October, flow er bud initiation occurred at 9 degrees to 20 degrees C, but the optim um range was 9 degrees-15 degrees C. Bulbs stored at 9 degrees C bloom ed earlier, but had fewer inflorescences when they were grown in a gre enhouse kept above 10 degrees C. Flower buds of bulbs stored at 10 deg rees C for 3 months were the earliest to differentiate; they flowered in mid-January if the greenhouse was kept above 10 degrees C. Bulbs ha rvested 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 degrees C for 3 months (ea rly July to October) and grown at or above 10 degrees C.