Delaying anthesis by dark treatment in Phalaenopsis

Delaying anthesis by dark treatment in Phalaenopsis 'Yukimai No. 24' was in vestigated. Plants kept at 20 degreesC in the dark survived for 80 days, wh ereas most of plants kept at 10 degreesC in the dark did not survive for 20 days. Plants exposed to light bloomed on Feb. 16, 1999, whereas the plants which kept at 20 degreesC in the dark during 20, 40, 60, and 80 days bloom ed on Mar. 15, Apr. 3, Apr. 28, and May 15, respectively. Although the leng th of stalk and flower size were unaffected by the 20 degreesC dark treatme nts, the number of flowers in the 80-day treatment was reduced slightly. Th ese results indicate that delaying anthesis in Phalaenopsis is possible by the dark treatment.