Abstract
Flowering responses of 'Regina', 'Carmen' (syn. 'Cana') and 'Wilhelmina' Alstroemeria to air and soil temperatures were studied for producing cut flowers in a soil cooling system. 1. Chilling requirements for flowering shoot production were 3∼6 weeks at 2°C for 'Wilhelmina', 6 weeks for 'Carmen' and more than 10 weeks for 'Regina'. 2. 'Regina' plants stopped producing flowering shoots when rhizomes were kept at 25 and 18°C but continued to produce flowers at 14°C, irrespective of air temperatures. 3. Rhizomes of 'Regina' plants, subjected to 15°C or lower for at least 6 hr per day, continued to produce flowering shoots although the number of vegetative shoots increased as compared to rhizomes exposed to a continuous chilling treatment. 4. Chilled 'Regina' and 'Carmen' plants ceased flowering subsequently when they were exposed to 28/22°C (12 hr day/12 hr night) for 4 and 10 weeks, respectively.
