• Horticultural Science & Technology
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• v.32 no.4
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• pp.454-462
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• 2014

This study was carried out to determine the effect of tree height on light transmission, spray penetration, tree growth performance, fruit quality attributes, and labor productivity in the slender-spindle system of 'Hongro'/M.9 apple trees. With increasing tree height, the light penetration into the internal parts of the canopy decreased, especially in the lower canopy. Leaf area index (LAI) increased with increasing tree height, thereby leading to a reduction in the extent of spray penetration into the interior of the canopy. With increasing tree height, shoot growth was more vigorous but produced slender shoots in the upper canopy compared to the lower canopy. Although the soluble solid content and coloration of fruit decreased, there was no difference in fruit firmness and acidity. In addition, the number of final fruit set increased, although the production of large fruit (> 305 g) decreased. The increase in tree height also significantly increased the labor required for practices such as thinning of flowers and fruits, pruning, and harvesting. Nevertheless, this problem of increased in labor input in taller trees would was eased by use of a mechanical lift. Utilizing a lift for thinning the flowers of trees 4.5 m in height saved 14.6 min per tree, compared to the use of ladder. Therefore, it is highly considerable that in order to enhance light transmission and fruit coloration, light conditions should be improved in the internal tree canopy of slender-spindle systems.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.44-48
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• 2008

This experiment was conducted to examine the effect of injecting cool air from an abandoned mine during the summer time for the growth of Doritaenopsis. The air temperature of abandoned mine in Boryeong was $12{\sim}14^{\circ}C$. The day and night temperatures were set at $22^{\circ}C$ and $20^{\circ}C$, respectively, from June to August in the experimental plastic house. This temperature range was within the suitable range for floral induction in Doritaenopsis. Average outside temperature was $28.4{\sim}32.8^{\circ}C$. The 3% of the crop developed flower stalk in 20 days after the treatment initiation, 65% in 45 days, and 100% in 90 days. The flower stalk length was short (48.7cm) in 30 days and long (62.4cm) in 60 days of treatment. The flower stalk length became longer as time passed. Flower spike and number of florets per stalk displayed the same tendency. Number of nodes was 6~7 and was not affected by the period. The first blooming appeared on 15th of September at 45 days and blooming tended to appear late as the period is lengthened. When the cool air from an abandoned mine was injected, the crop formed flower stalk three months earlier and bloomed four months earlier than the untreated control.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.263-268
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• 2014

This research was performed to investigate the effect of light source and light quality in night break treatment on the growth and flowering of standard chrysanthemum. It was processed 4 hours (22:00-02:00) night break using LED 590, 610, 630, 660, 680nm and fluorescent lamp (mixed light of 480+540+610nm) in standard chrysanthemum 'Baekma' and 'Jinba' for 40 days from transplanting. The days to flower budding from short-day treatment of 'Baekma' were the longgest at fluorescent treatment (21.3 days) and were the shorttest at LED 590nm treatment (15.8 days) among all treatments. The days to flower budding from short-day treatment of 'Jinba' was longger with 18.0 days, 17.8 days, and 17.7 days at the fluorescent, LED 610nm, and 660nm treatments. And it was the shortest with 15.1 days in LED 590nm treatment. Similarly, the days to flowering from short-day treatment of 'Baekma' was the longgest with 56.9 days at fluorescent treatment, and was the shorttest in 51.6 days about LED 590 nm treatment. The days to flowering from short-day treatment of 'Jinba' was longer at fluorescent (56.0 days) and LED 660nm (56.7 days) treatments and was shortest at LED 590nm (52.9 days) among all treatments. Therefore, inhibition of flower bud initiation and flowering were the most effective under fluorescent treatment in case of 'Baekma', and fluorescent and LED 660nm treatments in case of 'Jinba'. The length and weight of cut flower of 'Baekma' and 'Jinba' were most excellent in fluorescent treatment in which the floral differentiation suppression effect was the best. Consequently, as to the growth and flowering of standard chrysanthemum, the treatment which was suitable as the light source and light quality for night break is regarded as the fluorescent lamp, and also under LED 660nm up to a certain level.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.178-184
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• 2019

Strawberry ($Fragaria{\times}ananassa$) is one of the most important and popular fruit crops in the world, and 'Sulhyang' is one of the principal cultivars cultivated in the Republic of Korea for the domestic market. The growth and flower induction in strawberry is the process which influences directly on fruit bearing and yield of this crop. In this study, effect of benzyladenine (BA), gibberellic acid ($GA_3$), and salicylic acid (SA) on growth and flower bud induction in strawberry 'Sulhyang' was investigated. The 3-week-old runner plants, grown in 21-cell propagation trays, were potted and cultivated in growth chambers with $25^{\circ}C/15^{\circ}C$ (day/night) temperatures, 70% relative humidity (RH), and light intensity of $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density (PPFD) provided by white light emitting diodes (LEDs). The runner plants were treated with one of three concentrations, 0 (control), 100, and $200mg{\cdot}L^{-1}$ of BA, $GA_3$, or SA solution. The chemicals were sprayed two times on leaves of runner plants at an interval of two weeks. After 9 weeks the results showed that the application of all chemicals caused reduction of root length and chlorophyll (SPAD) content as compared to the control. The lowest chlorophyll (SPAD) content was recorded in plants treated with $GA_3$. However, the treatment of $200mg{\cdot}L^{-1}$ $GA_3$ promoted leaf area, leaf fresh weight, and plant fresh weight. The greatest flower induction (85%) and number of inflorescences (4.3 inflorescences per plant) were observed in the treatment of $200mg{\cdot}L^{-1}\;SA$, followed by $100mg{\cdot}L^{-1}\;SA$. Overall, results suggest that foliar application of $GA_3$ solution could accelerate plant growth, while foliar application of SA solution could induce hastened flowering. Further studies may be needed to find out the relationship between $GA_3$ and SA solutions treated in a combination, and the molecular mechanism involved in those responses observed.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.373-380
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• 2020

This study was conducted to investigate the effect of elevated temperatures on the growth and physiological responses of peach 'Mihong' (Prunus persica). We simulated three different temperature conditions in the sunlight phytotron rooms from April 25 to July 5, 2019; Control (average temperature in normal years in Jeonju city), +3.4℃ treatment (expecting temperature in mid-21st century), +5.7℃ treatment (expecting temperature in late 21st century). The shoot numbers and lengths were increased while the temperature was increased, but the leaf areas were not statistically different. The harvest dates were July 1, June 24 and 21 at the control, +3.4℃, and +5.7℃, respectively. The fruit weights were increased at +3.4℃ but decreased at +5.7℃ compared to the control. The tree yield was the highest in the +3.4℃ (2,898g), followed by the control (2,746g) and the +5.7℃ (2,404g). These are related to the result that the average of maximum photosynthesis rate at 3.4℃ (14.93μmol·CO₂·m^-2·s^-1) was higher than those at the control (13.79μmol·CO₂·m^-2·s^-1) and +5.7℃ (13.20μmol·CO₂·m^-2·s^-1) from mid-May to early June, the fruit growing season. Also, the stomatal densities were higher at the +3.4℃ (229ea/㎟), compared to the control (181ea/㎟). The rate of floral bud differentiation affecting the yield in the following year was the lowest at the +5.7℃. These results suggest that a temperature elevated to 3.4℃ in the future may give a positive effect on the yield and quality of peach 'Mihong' while a temperature elevated above 5.7℃ may affect negatively.

• Journal of Plant Biotechnology
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• v.42 no.1
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• pp.25-33
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• 2015

A PyrcpPR-10 gene with differentially expressed was isolated by using the suppression subtractive hybridization assay between '93-3-98' (highly resistant against scab caused by Venturia nashicola) and 'Sweat Skin'(highly susceptible) and analyzed the expression pattern according to organs and cultivars. The full length of PyrcpPR-10 was cloned as 743bp with 480bp's ORP, and was determined to encode a protein of 159 amino acid residues. On analyzing PyrcpPR-10 gene sequence compared with resistant and susceptible cultivars, 'Hwangsilri' (resistant), 'Gamcheonbae' (moderately resistant), 'Wonhwang' (moderately susceptible), 'Niitaka' (highly susceptible), and 'Sweat Skin' (highly susceptible) had identical gene sequence but 'Bartlett' (highly resistant) showed partly different sequences. The deduced amino acid sequence showed 64 ~ 98% homology and had the GXGGXG motif to known amino acid of other plants PR-10 by the BLAST X analysis. Among several organs or tissues, petal was showed highest expression level of PyrcpPR-10 gene followed by leaf, floral axis, bud, and bark. The expression level of PyrcpPR-10 gene was dramatically increased at 24 hr after inoculation in all cultivars and also up-regulated in accordance with resistant degree of cultivars. While resistant cultivars ('Bartlett', '93-3-98', and 'Hwangsilri') induced relatively high expression level of PyrcpPR-10 gene, susceptible cultivars ('Niitaka', and 'Sweat Skin') showed low expression level. PyrcpPR-10 gene is assumed that it is directly connected with defense mechanisms to pear scab.