• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.469-480
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• 2015

The study was conducted on the effects of time of defoliation on fruit quality of pear (Pyrus pyrifolia Nakai) trees, managing with low-pesticides, and regrowth of stem cuttings in vitro. Treatments included for 40% of uniform defoliation at early-August, end-August, and early-September, as well as control (no defoliation). Defoliation at early-September and control increased growth of water sprouts as well as concentrations of carbohydrates, total nitrogen, and free sugar in one-year old shoots. Defoliation at early-September and control increased fruit yield and mean fruit weight, with high soluble solids content and fruit surface color of $a^*$ observed for both defoliation at end-August and early-September. Defoliation at early-August increased rates of electrolyte leakage in stem cuttings at $-18^{\circ}C$ in vitro. There were no significantly different for germination rates of the cuttings between the treatments at -18 and $-21^{\circ}C$ in vitro, with the highest germination of the cuttings observed for defoliation at early-September and control at $-27^{\circ}C$. Therefore, orchard management should be performed to be minimized for defoliation of the spur leaves until end-August, causing from precipitation and pests.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.155-155
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• 2003

• Horticultural Science & Technology
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• v.34 no.3
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• pp.461-471
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• 2016

This study was conducted to establish an in vitro propagation system for sea-milkwort (Glaux maritima L.), which is an endangered coastal plant species with high horticultural value. Two phenotypes, 'Red type (RT)' and 'Pistachio type (PT)' based on the colors of stem and flower, were obtained from a personal horticulturist in 2009 and used for this study as plant materials. The stock plants showed typical morphologies in flower, capsule, and seed appearances as previously reported. Low temperature treatment at $4^{\circ}C$ for four or more weeks after in vitro sowing maximized seed germination percentage, indicating that imbibition of seed and subsequent low temperature treatment are crucial for its germination. The in vitro seedlings had phenotypic variation, falling into 'RT' and 'PT' classes like the stock plants. Although slight differences depending on genotype and medium were recognized, the fourth or fifth nodes detached from the in vitro seedlings revealed the best multiplication efficacy when estimated on the basis of total number of nodes of newly developed axillary shoots. In addition, the nodes from 'RT' and 'PT' regenerated the most shoots on medium supplemented with $0.5mg{\cdot}L^{-1}$ BA alone and $0.5mg{\cdot}L^{-1}$ BA plus $0.5mg{\cdot}L^{-1}$ IAA, respectively. The node culture-derived plantlets were well acclimatized in a culture room ex vitro and completed the pseudo-annual life cycle coincident with that in the natural salt march habitat with the current cultivation method of applying fresh water-irrigation under an inland environment. This work represents the first report of in vitro propagation of sea-milkwort. Thus, our study will contribute to exo-habitat conservation and natural habitat restoration of this endangered species in addition to development of a horticultural product.

• The Plant Pathology Journal
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• v.17 no.5
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• pp.264-270
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• 2001

The effects of leaf extracts of 14 different non-host plant species on in vitro conidial germination of Phaeoisariopsis personata, the causal organism of late leaf spot(LLS) of groundnut were evaluated. Aqueous and ethanol leaf extracts of Datura metel, Lawsonia inermis and aqueous leaf extracts of Sphaeranthus indicus at 25%(w/v) concentration completely inhibited the conidial germination of P. personata both at 24h and 48h after incubation. Aqueous leaf extracts of Blumea bifoliata, Eucalyptus globules, Ocimum sanctum and Pongamia pinnata, and ethanol leaf extracts of Azadirachta indica and S. indicus inhibited the conidial germination by >90%. Aqueous and ethanol leaf extract of L. inermis and S. indicus were highly inhibitory to conidial germination up to 1% concentration. Aqueous and ethanol leaf extracts of D. metel and ethanol leaf extract of A. indica were highly inhibitory to P. personata even at 0.01% (100 ppm) concentration. Ethanol leaf extract of A. indica up to $80^{\circ}$, aqueous leaf extracts of D. metel and S. indicus up to $100^{\circ}$, and L. inermis up to $60^{\circ}$, were highly stable and retained their fungitoxic effects. Extract of D. metel was antifungal even after 180 days when it was stored both at room temperature and $4^{\circ}$. Aqueous leaf extract of D. metel at 2% concentration effectively reduced the development of LLS by >60%, under greenhouse conditions both in prophylactic and simultaneous applications. Extracts of D. metel could be a potential economical and an eco-frendly alternative for control of late leaf spot, and its efficacy under field conditions is further being evaluated.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.292-297
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• 1995

We developed an in vitro assay method for evaluating plant growth promotion and providing an evidence that the growth promotion is rendered by growth enhancing factors. The amendment of culture filtrates of Trichoderma harzianum T95 and Gliocladium virens G872 and G872B in Murashige and Skoog (MS) agar medium enhanced the cotyledon growth of cucumber in terms of fresh weight and primary leaf area of cucumber cotyledon cuttings, of which the treatment of G. virens G872B was the most effective. The mycelial culture filtrate of G872B was more effective in the growth promotion than its conidial germling filtrate. The addition of 1% sucrose in MS mineral medium with 0.1% culture filtrates of the antagonists (T95 and G872B) was optimum for enhancing the effect of the filtrates on the growth of cotyledon cuttings in vitro. When cucumber seeds treated with G872B, Pseudomonas putida Pf3 or the G872B-Pf3 mixture were planted in a greenhouse, the rate of seed germination, biomass of shoot and root, and yield of cucumber fruits were increased, especially by G872B or the G872B-Pf3 mixture. Correspondingly, cucumber fruit yields in early to middle-cycles of harvest were significantly greater in the plots of G872B than the control and Pf3-treated plots, and the final yield was highest in the plots of the G872B-Pf3 mixture applications.

• Mycobiology
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• v.39 no.3
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• pp.194-199
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• 2011

Pepper anthracnose caused by Colletotrichum species is one of the most important limiting factors for pepper production in Korea, its management being strongly dependent on chemicals. The aim of this work was to evaluate the possibilities of using silver nanoparticles instead of commercial fungicides. In this study, we evaluated the effect of silver nanoparticles against pepper anthracnose under different culture conditions. Silver nanoparticles (WA-PR-WB13R) were applied at various concentrations to determine antifungal activities in vitro and in the field. The application of 100 ppm concentration of silver nanoparticles produced maximum inhibition of the growth of fungal hyphae as well as conidial germination in comparison to the control in vitro. In field trials, the inhibition of fungi was significantly high when silver nanoparticles were applied before disease outbreak on the plants. Scanning electron microscopy results indicated that the silver nanoparticles caused a detrimental effect on mycelial growth of Colletotrichum species.

• Journal of Forest and Environmental Science
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• v.37 no.2
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• pp.148-153
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• 2021

This study was carried out to establish in vitro propagation system influenced by plant growth regulators through organogenesis with three different seed sources (China, Mongolia and Russia) for conservation of genetic resources in Northeast Asia. The experiment compared two different carbon sources (commercial sugar, sucrose), which showed no significant differences in germination rate. Induced adventitious buds from leaf segments were found to be highly effective when supplemented with 1.0 mg/L BA, 1.0 mg/L Kinetin, and 5.0 mg/L IAA, in the case of Chinese origin 96.8%, Russian origin R-1: 95.6%, R-2: 85.6%, and Mongolian origin M-2: 77.8%. It was effective in BA and Kinetin with supplemented with IAA, respectively. Shooting development was also efficient in Woody Plant Media (WPM) supplemented with 1.0 mg/L BA, 1.0 mg/L Kinetin and 5.0 mg/L IAA.

• Mycobiology
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• v.46 no.1
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• pp.52-63
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• 2018

In our previous studies, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15 have been shown to be antagonistic to Aspergillus flavus in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against Aspergillus candidus, Aspergillus fumigatus, Penicillium fellutanum, and Penicillium islandicum, which are predominant in stored rice grains. In vitro and in vivo antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In in vitro tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In in vivo tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, B. megaterium KU143 and P. protegens AS15 may be potential biocontrol agents against Aspergillus and Penicillium spp. during rice grain storage.

• The Plant Pathology Journal
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• v.24 no.4
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• pp.453-460
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• 2008

In the course of in vitro and in vivo screening for bioherbicidal agents, a hyphomycete fungus, Myrothecium sp. F0252 was selected as a candidate for the biocontrol of weeds. The isolate was identified as Myrothecium roridum Tode ex. Fries based on the morphological characteristics and 18S ribosomal DNA sequence analysis and registered as Myrothecium roridum F0252. In order to evaluate the in vitro effect of M. roridum F0252 on germination of ladino clover and white clover (Trifolium repens L.) seeds, spore solution of the fungus was employed in two concentrations, $6.5{\times}10^6$ and $2.5{\times}10^7$ spores per mL and then inoculated to the seeds. The fungal spores inhibited the seed germination, infected the seedlings, and caused an abnormal withering and inhibition of seedling growth. In addition, when the herbicidal activity of crude ethyl acetate extract from the liquid culture was assessed on a mini-plant, duck-weed (Lemna paucicostata (L.) Hegelm.), the extract showed high inhibitory effect at the level of $12.5{\mu}g$ per mL. On the other hand, in vivo herbicidal activity of M. roridum F0252 was evaluated by a whole plant spray method. M. roridum F0252 exhibited strong and broad-spectrum herbicidal activity. The herbicidal values ranged from 95-100% against 7 weeds, including Abutilon avicennae and Xanthium strumarium, and 70-80% against Digitaria sanguinalis and Sagittaria pygmaea. When the nutritional utilization (95 carbon sources) pattern of M. roridum F0252 was investigated, it varied with water activity ($a_w$) and temperature conditions, supplying good, basic information in regard to nutritional utilization for proper cultivation and formulation. Our results showed that M. roridum F0252 might be used as a potential biocontrol agent against weedy plants.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.269-277
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• 2015

Anthracnose caused by Colletotrichum gloeosporioides has been destructive during pepper fruit production in outdoor fields in Korea. In vitro antifungal activities of 15 different plant essential oils or its components were evaluated during conidial germination and mycelial growth of C. gloeosporioides. In vitro conidial germination was most drastically inhibited by vapour treatments with carvacrol, cinnamon oil, trans-cinnamaldehyde, citral, p-cymene and linalool. Inhibition of the mycelial growth by indirect vapour treatment with essential oils was also demonstrated compared with untreated control. Carvacrol, cinnamon oil, trans-cinnamaldehyde, citral and eugenol were among the most inhibitory plant essential oils by the indirect antifungal efficacies. Plant protection efficacies of the plant essential oils were demonstrated by reduced lesion diameter on the C. gloeosporioides-inoculated immature green pepper fruits compared to the inoculated control fruits without any plant essential oil treatment. In planta test showed that all plant essential oils tested in this study demonstrated plant protection efficacies against pepper fruit anthracnose with similar levels. Thus, application of different plant essential oils can be used for ecofriendly disease management of anthracnose during pepper fruit production.