• Horticultural Science & Technology
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• v.19 no.4
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• pp.579-584
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• 2001

This experiment was conducted to investigate the effect of soil moisture content on cut flower quality of Gypsophila paniculata L. 'Bristol Fairy' in spring and autumn cultivations. The soil moisture potential (SMP) set point for irrigation was either -3.2 or -10.0kPa in the vegetative growth stage, and -10.0, -31.6, or -79.4kPa after the budding stage. When soil moisture reached at each set SMP point, 10 mm water was drip-irrigated. Tendency of flowering was earlier as SMP set point was lower in both vegetative growth and after budding stages. No other flower characteristics were found among other treatments. In both spring and autumn cultivations, as SMP set point was lower, the low primary branch length and upper internode length were decreased, the stem firmness was increased, and curvature of cut flower stem was decreased. Especially, in autumn, the higher the SMP set point, the higher the low primary branch than the apex, thus the paniculate inflorescence was deeply destroyed. Yield in spring cultivation was not significantly different among treatments, while that in autumn cultivation increased as the lower the SMP value. It is thought that optimal imgation points during vegetative growth and after budding stages to produce high quality cut flowers are -10.0 and -79.4kPa, respectively.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.539-548
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• 2011

This study was conducted to control unseasonable flowering in a standard chrysanthemum 'Baekma' bred in Korea by 2-chloroethylphosphonic acid (ethephon) and night temperature (NT) through suppression of the transition from a vegetative to a reproductive stage under long day length caused by high NT in summer season. Ethephon was applied either once or twice at a concentration of 0, 200, 400, or $800mg{\cdot}L^{-1}$. The NT within controlled mini-plastic houses was maintained at 13, 17, or $21^{\circ}C$. The NT at $13^{\circ}C$ showed the greatest inhibiting effect of unseasonable flowering among all NTs regardless of various combinations of ethephon concentration and frequency. Moreover, the inhibition tendency of unseasonable flowering was distinctly decreased in a NT-dependant manner. Higher NTs reduced cut flower length and number of leaves, but increased the number of young leaves attached to top part of the flower. Higher ethephon concentrations and lower NTs increased cut flower length and the fresh weight of total, stem, and leaves due to the extension of vegetative growth period. Thus, if it is difficult to control the NT below $21^{\circ}C$ in greenhouses in the summer season, we recommended to spray more than $200mg{\cdot}L^{-1}$ ethephon once after planting to suppress unseasonable flowering and to ensure sufficient length of cut flowers.