Articles
Recent progress in night-break lighting technique based on photoperiodism of chrysanthemum
Article number
1237_17
Pages
129 – 136
Language
English
Abstract
Flowering control is one of the most important techniques in floriculture.
The control of day length makes year-round cut-chrysanthemum flower production possible.
Night-break is the most widely used flowering control method in both cut flower and pot chrysanthemum production.
In this study, we investigated the effects of night-break, night-break time, and light quality on chrysanthemum flowering.
On comparing the wavelengths of red (R) light used for night-breaks, it was observed that the inhibition effect on flowering was higher in the wavelength range of 620-640 nm than at 660 nm, in which the conversion efficiency of phytochrome is high.
The effect of R light and R + far red (FR) light on the inhibition of flowering changes with the length of night-break.
The effect of R light is higher with a short night-break.
On the other hand, when the duration of night-break is long, both R and R + FR light showed equivalent inhibition effects, and the effect of R + FR light was higher than R light in some varieties.
The most effective time for night-break was not the middle of the dark period, but near the end of the cultivar-specific critical dark period.
As the night-break time was extended, the inhibitory effect on flowering initially increased with night-break time up to a certain time period, beyond which the effect decreased again.
The results obtained here are contrary to current perspective on night-break.
Based on these findings, we propose a new night-break protocol for the inhibition of flowering in chrysanthemum.
The control of day length makes year-round cut-chrysanthemum flower production possible.
Night-break is the most widely used flowering control method in both cut flower and pot chrysanthemum production.
In this study, we investigated the effects of night-break, night-break time, and light quality on chrysanthemum flowering.
On comparing the wavelengths of red (R) light used for night-breaks, it was observed that the inhibition effect on flowering was higher in the wavelength range of 620-640 nm than at 660 nm, in which the conversion efficiency of phytochrome is high.
The effect of R light and R + far red (FR) light on the inhibition of flowering changes with the length of night-break.
The effect of R light is higher with a short night-break.
On the other hand, when the duration of night-break is long, both R and R + FR light showed equivalent inhibition effects, and the effect of R + FR light was higher than R light in some varieties.
The most effective time for night-break was not the middle of the dark period, but near the end of the cultivar-specific critical dark period.
As the night-break time was extended, the inhibitory effect on flowering initially increased with night-break time up to a certain time period, beyond which the effect decreased again.
The results obtained here are contrary to current perspective on night-break.
Based on these findings, we propose a new night-break protocol for the inhibition of flowering in chrysanthemum.
Authors
R. Hakuzan, S. Fukai
Keywords
critical night length, far red light, light quality, red light
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