Articles
INTERRUPTED COOLING AS AN ALTERNATIVE TO CASE-COOLED OR CONTROLLED TEMPERATURE FORCING OF EASTER LILIES
Article number
673_95
Pages
685 – 690
Language
English
Abstract
Easter lily (Lilium longiflorum) bulbs have to be exposed to cool temperatures (vernalization) to obtain uniform emergence and flowering in the spring.
For this purpose, a number of cooling techniques are used, namely natural cooling, case-cooling (CC) and controlled temperature forcing (CTF). Case-cooling is the technique, whereby the bulbs after digging are packed in a wooden case together with moist peatmoss, exposed to cool temperatures at 5-6°C for six weeks and then planted.
CTF is the technique where the bulbs are planted first in a pot, rooted for 2-3 weeks under controlled temperatures (15-18°C), and then the pots with bulb are moved to a cooler and kept at 6-7°C for six weeks prior to forcing in the greenhouse.
Our research has focused on a new technique of bulb vernalization named interrupted cooling (IC). This technique is based on a combination of case-cooling and CTF. The bulbs are first vernalized at 6°C for three weeks in the case, then planted in pots for a rooting period of 2-3 weeks, and then cooled again at 6°C for three weeks, so that the bulb will still receive six weeks of cooling.
The objectives of this study were to determine whether IC is a feasible alternative to either CTF or CC forcing and whether rooting temperature (14, 18, 22, and 26°C) influences the growth and development of Easter lily Nellie White. Plant parameters (flowering date, number of buds, stem height and stem diameter) showed that plant morphology and forcing using IC were similar to CTF. The number of flowers, leaves, forcing time and plant height increased linearly with rooting temperature similarly for both IC and CTF. The base of the lily stem of the IC and CTF plants both showed longer leaves, with short internodes and a thicker stem compared to CC plants.
Interrupted cooling proved to be a good alternative for vernalization of Easter lilies.
For this purpose, a number of cooling techniques are used, namely natural cooling, case-cooling (CC) and controlled temperature forcing (CTF). Case-cooling is the technique, whereby the bulbs after digging are packed in a wooden case together with moist peatmoss, exposed to cool temperatures at 5-6°C for six weeks and then planted.
CTF is the technique where the bulbs are planted first in a pot, rooted for 2-3 weeks under controlled temperatures (15-18°C), and then the pots with bulb are moved to a cooler and kept at 6-7°C for six weeks prior to forcing in the greenhouse.
Our research has focused on a new technique of bulb vernalization named interrupted cooling (IC). This technique is based on a combination of case-cooling and CTF. The bulbs are first vernalized at 6°C for three weeks in the case, then planted in pots for a rooting period of 2-3 weeks, and then cooled again at 6°C for three weeks, so that the bulb will still receive six weeks of cooling.
The objectives of this study were to determine whether IC is a feasible alternative to either CTF or CC forcing and whether rooting temperature (14, 18, 22, and 26°C) influences the growth and development of Easter lily Nellie White. Plant parameters (flowering date, number of buds, stem height and stem diameter) showed that plant morphology and forcing using IC were similar to CTF. The number of flowers, leaves, forcing time and plant height increased linearly with rooting temperature similarly for both IC and CTF. The base of the lily stem of the IC and CTF plants both showed longer leaves, with short internodes and a thicker stem compared to CC plants.
Interrupted cooling proved to be a good alternative for vernalization of Easter lilies.
Publication
Authors
T.J. Blom, D. Kerec, R. Kamenetsky
Keywords
case-cooling, CTF, flowering, Lilium longiflorum, pot cooling
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