ISHS Acta Horticulturae 197: Working-party on Greenhouse Chrysanthemum
EFFECTS OF DAY AND NIGHT TEMPERATURE ON GROWTH AND FLOWERING OF CHRYSANTHEMUM |
| Authors: | P.J.A.L. de Lint, G. Heij |
| DOI: | 10.17660/ActaHortic.1987.197.5 |
| Abstract:
In the 24-compartment house at Naaldwijk Research Station twelve temperature combinations were maintained, in duplicate, throughout culture period of chrysanthemum, viz.: four night temperatures: 14, 17, 21 and 25°C, and three day temperatures: 14, 17 and 21°C. In each compartment three successive plantings were set out, viz.: 22 October and 5 and 19 November 1981. Plantings comprised four culture varieties, viz.: Spider, Horim, Westland and Pink Gin. Plants were lit for longday conditions with incandescent lamps. Lamps were off during short day treatment from 14 December 1981 to 4 January 1982. Main growth characteristics were registered throughout the experiment. The data show that plant fresh weight is almost insensitive to temperature over the range of temperatures tested. Stem length is enhanced by higher temperature, both day and night. Stem quality (g/cm) consequently is reduced with higher temperature. Leaf number demonstrates two temperature effects: during the vegetative long day phase, leaf numbers are higher with higher temperature; due to flower bud initiation in short day leaf number is stopped earlier or later depending on the temperature influence on flower induction. Bud formation is retarded below 17°C and above 21°C. This response is observed for night temperatures only. The position and the steepness of this optimum are cultivar-dependent. In general, chrysanthemum grows faster at higher temperatures, but flower bud formation (in short days) is optimally fast at moderate temperatures of about 20°C. | |
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