EFFECTS OF TEMPERATURE ON THE GROWTH AND FLOWERING OF ALLIUM-COWANII LINDL

In this study, the growth periodicity of plants of Allium cowanii (syn . A. neapolitanum with large flowers), grown in an unheated plastic ho use, was clarified. Simultaneously, the effect of temperature on the i nitiation and development of flower buds was investigated. A bulb show s a sympodial branching system from mid-September to early December; 2 to 3 inflorescences are initiated as a result of repeated sympodial b ranching. The first inflorescence initiated in mid-September, the prim ordium of florets becoming visible in early and mid-October; the tepal s and stamen are differentiated from late October to mid-November, lea ding to anthesis in mid-February of the following year. A second inflo rescence is initiated in mid-October and bears flowers in early March. To assess a) the starting time of bulb storage, b) duration of storag e, and c) storage temperature, bulbs were stored at 15 degrees, 20 deg rees, 25 degrees C, or 30 degrees C from 1 July to 1 October or at 9 d egrees, 15 degrees, 20 degrees, 25 degrees C, or 30 degrees C from 1 A ugust to 1 October. At the end of the storage periods, the initiation of the first inflorescence was observed at all temperetures below 25 d egrees C, but the optimum temperature was 15 degrees-20 degrees C. Mos t bulbs stored at 30 degrees C were in the vegetative state. When bulb s were grown in a greenhouse kept above 10 degrees C after different p eriods of temperature treatment, those stored at lower temperatures bl oomed earlier, except for those stored at 15 degrees C from 1 July; th ey had low percentages of flowering plants. However, the number of flo wering inflorescences per bulb was small. Plants grown above 20 degree s C after planting in early October flowered 18 days earlier than did those grown at above 10 degrees C. The early blooming scapes were shor ter and had fewer florets than did the late blooming ones.