• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.171-176
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• 2009

Hydroponic culture has been developed to control soilborn diseases, to increase yield and to enhance the quality of vegetable, The pathogen could be detected from infected plant materials, hydroponic tanks, culture solution and solid media of the severely infected greenhouse, The density of pathogen population was coincided with the severity of disease incidence, For example, 1,900cfu m$L^{-1}$ pf pathogens were counted from tomato plants sampled in a 20% diseased greenhouse. The pathogens may be introduced in the greenhouse through the contaminated soil surrounding the house and/or through the infected young seedlings grown on the nursery soil. Also, not detected to Ralstonia solanacearum from tomato seeds (House Momotaro, Bbaebbae, Ggoggo, and Minicarol cultivar) selling at a market.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.6
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• pp.1-8
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• 2017

The purpose of this study was to provide basic data for development of environmental design technology for greenhouses constructed in reclaimed lands. We analyzed the climatic conditions around seven major reclaimed land areas in Korea, which have a plan to install advanced horticultural complexes. The characteristics of heating load through the thermal environment measurement of the greenhouse in Saemangeum were analyzed. The part to be applied to the environmental design of the greenhouses in reclaimed lands were reviewed. The overall heat transfer coefficient of the experimental greenhouse with the aluminum screen and multi-layer thermal curtain averaged $3.79W/m^2^{\circ}C$. It represents a 44 % heat savings rate compared with plastic greenhouses with a single covering, which was significantly lower than that of the common greenhouses with 2-layer thermal curtains. This is because the experimental greenhouse was installed on reclaimed land and wind was stronger than the inland area. Among the total heating load, the transmission heat loss accounted for 96.4~99.9 %, and the infiltration loss and the ground heat exchange were low. Therefore, it is necessary to take countermeasures to minimize the transmission heat loss for greenhouses constructed in reclaimed lands. As the reclaimed land is located on the seaside, the wind is stronger than the inland area, and the fog is frequent. Especially, Saemangeum area has 2.6 times stronger wind speed and 3.4 times longer fog duration than the inland area. In designing the heating systems for greenhouses in reclaimed lands, it is considered that the maximum heating load should be calculated by applying the wind coefficient larger than the inland area. It is reasonable to estimate the operation cost of the heating system by applying the adjustment factor 10 % larger than the average in calculating the seasonal heating load.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.14-20
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• 2023

Light is an important factor that influences the growth and development of flowering plants. The present study investigated the effects of in vitro acclimatization to different light colors (white light (WL; control), blue light (BL; 447 nm), green light (GL; 519 nm), and red light (RL; 667 nm)) on the growth of petunia (Petunia hybrida) and of hardening cultivation of plant transferred form in vitro to a greenhouse under sunlight. Compared to the control, the shoot length and leaf width of Petunia increased by 42% and 11.7%, respectively, after acclimatization to BL and the shoot growth increased by 29.3% after acclimatization to RL. The chlorophyll and carotenoid contents after acclimatization to BL and GL were 16.7% and 11.3% higher, respectively, and 14.4% and 11.9% higher, respectively, than those in the control. During greenhouse cultivation, the shoot length increased by 16.7% and 11.3%, respectively, after acclimatization to BL and RL, respectively, and the leaf length and leaf width increased by 14.4% and 11.9%, respectively, after acclimatization to GL. While dry weight of root of GL and BL was not significant difference in vitro, increased by 59.0% and 22.9% ex vitro than that of WL. Thus, acclimatization to BL increased the shoot growth and leaf chlorophyll contents, and acclimatization to GL and RL enhanced shoot and root growth, in petunia.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.677-691
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• 2016

To assess South Korean commercial tomato cultivars, regular and cherry tomato cultivars were grown in the greenhouse and evaluated for color attributes, titratable acidity, pH, total soluble solids, carotenoids (lycopene and ${\beta}$-carotene), total phenols, flavonoids, vitamin C, and antioxidant activity. Significant differences (p < 0.05 using Duncan's multiple range test (DMRT)) were observed in the levels of most phytochemicals, quality parameters, and antioxidant activity among the twenty South Korean tomato cultivars tested. Lycopene and ${\beta}$-carotene contents varied significantly (p < 0.05 using DMRT), from $0.95mg{\cdot}100g^{-1}$ to $5.12mg{\cdot}100g^{-1}$ and $0.65mg{\cdot}100g^{-1}$ to $3.56mg{\cdot}100g^{-1}$ of fresh weight, respectively. ${\beta}$-carotene contents exhibited the highest genetic variation (59.2%), followed by naringenin (52.8%) and other phytochemicals. Most of the cherry tomato cultivars had statistically higher levels (p < 0.05 using DMRT) of carotenoids, phenols, flavonoids, vitamin C, and antioxidant activity compared to the regular tomato varieties, suggesting their higher nutritional value. Lycopene content was highest in the cultivars YoYo, Jicored, Titi-Chal, TY-Endorphin, and Rubyking. Cultivars Rubyking, TY-Endorphin, and Titi-Chal also showed relatively higher antioxidant activities in three assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric ion reducing antioxidant power (FRAP) assays. All the antioxidants, except luteolin, were positively correlated with antioxidant activities; the highest correlation was observed between total phenol and antioxidant activities, followed by the correlation between rutin and vitamin C. Cultivars identified to have superior nutritional status would be useful in tomato breeding programs to further improve quality and health benefits of tomatoes for the fresh and processed markets.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.381-387
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• 2020

Various studies have been attempted to estimate and measure the fresh weight of crops. However, no studies have used raw images of sweet peppers to estimate fresh weight. Recently, image processing research using convolution neural network (CNN) that can use raw data is increasing. In this study, the crop fresh weight was estimated by using the images of sweet peppers as inputs of CNN. The experiment was performed in a greenhouse growing sweet pepper (Capsicum annuum L.). The fresh weight, the output of the CNN, was regressed based on the data collected through destructive investigation. The highest coefficient of determination (R²) of the trained CNN was 0.95. The estimated fresh weight showed a very similar trend to the actual measured value.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.623-627
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• 2014

Curcuma alismatifolia is becoming popular for cut flowers and potted plants due to its long inflorescence with many showy pink flowers. It is propagated by rhizomes and inflorescences that are similar to those of lotus. However, initiation of inflorescence development of each bract and flower has not been investigated. Therefore, this experiment was conducted to study the inflorescence development of Curcuma alismatifolia 'Chiangmai Pink' by scanning electron microscopy (SEM). When new shoots grew to 15-20 cm in a greenhouse at $25^{\circ}C$, the first bract initiated with a dome-shaped inflorescence apex, followed by initiation of additional bracts, forming the shape of the flower head. Florets were subtended by the first bract when five to seven bracts were formed. Four to six florets were subtended by each bract. The floret positioned in the center initiated and progressed upward first. When the center florets in the upper bracts were formed, florets next to the center floret subtended by the first bract were formed, and formation of the axillary florets progressed upward in sequential order.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.99-107
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• 1992

Effects of the indigenous Vesicular-arbuscular mycurrhizal fungi(VAMF) on early growth response of greenhouse grown crops were experimented. This study was done to evaluate the benefit of indigenous VAMF inoculation on the early growth and the subsequent growth after transplanting of some crops such as cucumber, tomato, hot pepper, eggplant, and melon. Leaf area, shoot dry weight, and plant length of mycorrhizal greenhouse crops showed the tendency of significant or no significant increase over control plants receiving no inoculation. The levels of VA mycorrhizal colonization were increased with plant growth, and infection rates of horticultural crop except hot pepper around one week after transplanting were decreased, while that of 8 weeks after emergence of mycorrhizal seedlings were increased again and infected by around 50% at harvesting time. In spore densities in the rhizosphere soil of craps experimented, the number of spore ranged from $72.7{\pm}26.3$ to $100{\pm}10.3g^1$ on dried soil basis and high density showed in both cucumber and tomato. Total nitrogen contents in shoots were lower in the mycorrhizal plants than non-mycorrhizal one, whereas P uptake in mycorrhizal hot pepper and tomato were highly ramarkable. The K contents in the shoots of mycorrhizal cucumber and eggplent were highly enhanced. Inoculation of the indigenous VAMF enhanced shoot Ca and Mg in both tomoto and melon. The contents of Fe, Zn, Mn and Cu in shoots of mycorrhizal crops were higher than non-mycorrhizal plants and vice versa in case of eggplent. Inoculation of the indigenous VAMF to horticultural crops were effective for alleviation of transplanting shock, and pretransplanting infection improved subsequent growth by reducing the time required for establishment of a functional mycorrhizal symbiosis following transplanting.

• Korean journal of applied entomology
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• v.52 no.2
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• pp.109-113
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• 2013

A greenhouse soil infested with an obligate nematode parasitic bacterium, Pasteuria penetrans, was used to test the effect of temperatures on the endospore attachment to root-knot nematode, Meloidogyne arenaria, juveniles (J2). Freshly hatched J2s were inoculated to the soil in petri dish and incubated under different temperatures of $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, and $35^{\circ}C$ for 7 days. The endospore attachment rates were 100% in all the temperatures, while the number of endospores attached per J2 was highest in $25^{\circ}C$ with 28.3 endospores/J2 followed by 20.2, 18.6, and 13.6 in $30^{\circ}C$, $20^{\circ}C$, and $35^{\circ}C$, respectively. When the soil was pre-treated under different temperatures before the J2 inoculation, the endospore attachment rates significantly decreased from 60% in room temperature to $25^{\circ}C$, 31.7, 8.3, 5.0, and 0% after the soil incubation in $-30^{\circ}C$, $4^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $100^{\circ}C$ for 10 days, respectively. The endospore numbers attached per J2 were 3.5, 4.3, 1, 1, and 0 when the soil was pre-treated in $-30^{\circ}C$, $4^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $100^{\circ}C$, respectively, which were lower than 5.3/J2 of room temperature treated soil. The P. penetrans isolate in the soil showed nematode species-specific endospore attachment characteristics with 100% attachment rate only on M. arenaria J2s while the rates were 0% on M. hapla and M. incognita J2s.

• Research in Plant Disease
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• v.15 no.3
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• pp.187-192
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• 2009

Pepper powdery mildew, Leveillula taurica is one of the most important pathogens of pepper in the greenhouses and fields in Korea and is becoming a worldwide disease. These experiments were carried out to investigate the optimal germination, disease development conditions, disease incidence and effective inoculation methods of pepper powdery mildew. The incidence of powdery mildew was investigated throughout the country based on the major pepper growing areas in 2009. The average rate of infected leaves ranged from 15.3% to 81.8% in greenhouses and fields. Powdery mildew incidences were more severe in greenhouses than those of fields. The optimal temperature for conidial germination was $25^{\circ}C$ and showed the highest germination at 6 hs after treatment. The range of temperature for germination was $10^{\circ}C$ to $35^{\circ}C$. Temperature of greater than $30^{\circ}C$ and below $20^{\circ}C$ affected the abnormal germination and germ tube elongation. The optimal relative humidity for germination and germ tube elongation was 85% and germination increased as relative humidity increased. Disease development started 8 days after inoculation and showed the highest disease severity at 15 days in greenhouse and field regardless of varieties. Among three different inoculation methods tested the spore dropping method was better than touching with infected leaves and spraying with spore suspension. However, the method has limitation in mass inoculation due to the amount of time consumed.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.201-209
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• 2006

Five strains of Korean entomopathogenic nematodes (EPN), steinernematids and heterorhabditids were evaluated and tried in laboratory, pot, and vegetable greenhouses for environmentally friendly control of diamondback moth (DBM), Plutella xyiostella, from 2002 to 2005. LC$_{50}$ values of five EPN strains against DBM were different depending on nematode strain and DBM instar. LC$_{50}$ value of Steinernema carpocapsae GSN1 (GSN1) was the lowest representing 2.6$\sim$3.9 infective juveniles (Ijs, 3rd stage) to 2nd to 4th instars of DBM. Pathogenicity of five effective strains against DBM was different depending on nematode strain, concentration, application times, and vegetable in pot. The most effective nematode was GSN1. Steinernema spp. was more effective than Heterorhabditis spp. against DBM. Two or three times of applications of EPN were effective regardless of nematode strain and concentration in pot. Efficacy of EPN was different depending on vegetable species. Efficacy was higher on Chinese cabbage, red mustard, and Ssamchoo than that on cabbage, kale, and leaf broccoli. Efficacy of GSN1, Steinernema GSNUS-10, Steinernema CSNUS-14, and Heterorhabditis GSNUH-1 was variable depending on nematode strain, concentration, application times, and vegetable in greenhouse experiments. GSN1 was the most effective and 100,000 infective juveniles per m$^2$(=$1\times10^9$ Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale in greenhouse.