高冷地一貫生産におけるシンビジウムの生育・開花に及ぼす開花リード発生時の低夜温管理の影響

Abstract

The effects of low night temperature management in winter on growth and flowering of Cymbidium orchid were investigated in a greenhouse in a highland environment, using two varieties. The minimum night temperature was set at either 5°C or 15°C (control) from September 24, 1998 to May 31, 1999. In the other treatments, minimum night temperatures were set at 5°C then raised to 15°C on January 20, February 3, February 17, or March 3. The growth of lead bulbs was slightly poor in 5°C treatments in comparison with the control. However, the high-quality product ratio of 5°C treatments was equal or higher, and the flowering date was equal or earlier than the control. The treatment when the minimum night temperature was raised to 15°C, from 5°C on February 17 had the earliest flowering date, and fuel costs were about 60% less than the control. A low-cost way to manage the temperature for producing higher-quality Cymbidium plants is to set the minimum night temperature at 5°C from fall to spring, then raise it to 15°C after mid-February when the amount of sunlight has increased, promoting good flowering.