Articles
Different photoperiod regimes with LED lighting influence growth of container grown budded and non-budded citrus nursery trees
Article number
1337_41
Pages
305 – 312
Language
English
Abstract
Nursery citrus trees in California must be grown in insect exclusion facilities to be protected against Huanglongbing (HLB), a deadly disease spread by the Asian citrus psyllid.
Faster year-round propagation is critical for citrus nurseries to offset the investment in new exclusion facilities, but nurseries currently face serious problems of poor bud push and slow scion growth in fall-budded container grown trees.
Therefore, the purpose of this study was to explore the effect of supplemental LED lighting technique on improving container citrus tree growth and propagation efficiency. 72 trees of the common Carrizo citrange rootstock with and without Clementine Mandarin scion were placed in growth chambers under four photoperiod treatments: T1, 10 h LED with low supplemental light extension of day length (EoD-10); T2, 10 h LED with low supplemental night interruption (NI-10); T3, 10 h supplemental far-red light; and T4, 10 h LED. Light spectrum of LEDs were adjusted to 90 red and 10 blue light ratio.
The trees were maintained in the growth chambers at 21/13°C day/night temperatures and 80% RH for 12 weeks.
This experiment was run two times.
The results showed that there were significantly higher leaf count and average shoot growth in NI-10 and EoD-10 than in 10 h LED in both budded and non-budded trees.
Far-red supplemental light treatment was able to increase significant shoot length in budded trees as compared to 10 h LED. The efficacy of low supplemental lights (10 μmol m‑2 s‑1) below the light compensation point and the partitioning of dry weight between roots, stems, and leaves of trees in the different photoperiodic treatments indicated phytochrome-mediated control of growth in citrus trees.
Faster year-round propagation is critical for citrus nurseries to offset the investment in new exclusion facilities, but nurseries currently face serious problems of poor bud push and slow scion growth in fall-budded container grown trees.
Therefore, the purpose of this study was to explore the effect of supplemental LED lighting technique on improving container citrus tree growth and propagation efficiency. 72 trees of the common Carrizo citrange rootstock with and without Clementine Mandarin scion were placed in growth chambers under four photoperiod treatments: T1, 10 h LED with low supplemental light extension of day length (EoD-10); T2, 10 h LED with low supplemental night interruption (NI-10); T3, 10 h supplemental far-red light; and T4, 10 h LED. Light spectrum of LEDs were adjusted to 90 red and 10 blue light ratio.
The trees were maintained in the growth chambers at 21/13°C day/night temperatures and 80% RH for 12 weeks.
This experiment was run two times.
The results showed that there were significantly higher leaf count and average shoot growth in NI-10 and EoD-10 than in 10 h LED in both budded and non-budded trees.
Far-red supplemental light treatment was able to increase significant shoot length in budded trees as compared to 10 h LED. The efficacy of low supplemental lights (10 μmol m‑2 s‑1) below the light compensation point and the partitioning of dry weight between roots, stems, and leaves of trees in the different photoperiodic treatments indicated phytochrome-mediated control of growth in citrus trees.
Authors
H. Singh, M. Khezri, S. Benes, J. Bushoven, G. Brar
Keywords
extension of day length (EoD), night interrupt (NI), photoperiod
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