265 Influence of Frozen-in Storage Duration and Forcing Temperature on Flowering of Oriental Hybrid Lilies

Abstract

The effect of long-term storage of lily bulbs at -2 °C and of high temperatures on plant height and floral abnormalities was investigated with Oriental hybrid lilies in 1997-2000. `Acapulco' and `Simplon' bulbs were stored frozen at -2 °C and forced in regular greenhouses with varying temperatures between 12 to 30 °C, depending on the season, and also air-conditioned greenhouses where temperatures were maintained year-round at 15.5 to 16 °C or 18 to 18.5 °C. Floral development was observed under a scanning electron microscope after -2 °C treatment. At flowering, stem length with dried and green leaves, number of leaves, and number of normal and abnormal flowers were counted. Although frozen-in storage duration affected plant height, flowering, and the number of abnormal flowers, high temperatures during summer significantly affected the speed of flowering, plant height, and the number of abnormal flowers. High temperature damage can be prevented by growing bulbs at low temperatures immediately after planting the frozen-in stored bulbs. Bulbs can be stored for 12 months to produce quality cut Oriental hybrid lily flowers.