MODELING LIGHT AND TEMPERATURE EFFECTS ON CHRYSANTHEMUM MORIFOLIUM

Functions relating developmental time and shoot length to day temperature (DT), night temperature (NT) and irradiance were evaluated for their ability to produce a flowering chrysanthemum in a greenhouse on a preselected date with a preselected shoot length.
Daily calculation of DT required the entry of a NT and an irradiance value.
Likewise, daily calculation of NT required the entry of a DT and an irradiance value.
Several strategies for determining the required DT, NT and irradiance values were evaluated.
DT or NT values were entered based on one of the following strategies: 1) cumulative average of DT or NT from initiation of experiment, 2) actual DT or NT from the previous day or night or 3) a weighted average from the previous 5 days.
Irradiance values were entered based on: 1) a cumulative average, 2) a predicted value for the day or 3) a weighted average from the previous 5 days.
Of 5 DT/NT strategy combinations evaluated, use of cumulative NT and predicted irradiation for calculation of DT and cumulative DT and actual irradiation for calculation of NT resulted in plants flowering most similar to the preselected values.

Symposium Greenhouse Climate and its Control

M.G. Karlsson, R.D. Heins

https://doi.org/10.17660/ActaHortic.1985.174.28