• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.49-69
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• 1988

In order to develop a cropping system that can produce garlic in the period of short supply from March to April, effects of low temperature treatment of seed bulbs and planting dates, starting date of low temperature treatment, days of low temperature treatment on plant growth, maturity and yield were studied in Southern strain, 'Namhae' and in Northern strain, 'Euiseong' of garlic (Allium sativum). The results obtained were as follows. In Sorthern strain, sprouting was significantly enhanced by low temperature treatment only in Sep. 14, and Sep. 29 plantings. Days to sprout were least in 30 days of low temperature treatment of Sep. 14 planting and in 45 days treatment of Sep. 29 planting. When considering on the beginning date of low temperature treatment, a marked difference was observed between treatments started before July 31 and after Aug. 15. Sprouting was most enhanced in 45 days low temperature treatment of Aug. 15 and Aug. 30 plantings. In Northern strain, sprouting was en hanced by low temperature treatment in planting from Sep. 29 to Nov. 13 and low temperature treatment for 60 days was most effective. Effect of low temperature treatment on early plant growth was observed in Sep. 14 and Sep. 29 plantings, but the effect on plant growth at intermediate stage or thereafter was observed in up to Oct. 29 plantings. Optimun days for low temperature treatment on growth enhancement was 45 and 60 days in Southern strain and 60 days in Northern strain in each planting dates. In Southern strain, the longer the low temperature treatment and the later the planting date the less the number of leaves developed. In Northern strain, normal leaves were not developed in plantings from Sep. 14 to Nov. 13. In Southern strain, clove differentiation and bulbing were earlist in 45 and 60 days treatment of Sep. 14, Sep. 29, and Oct. 14 planting initiated on July 31 and Aug. 15. In Northern strain, clove differentiation and bulbing were earlist in 60 days treatment of Oct. 14 planting initiated on Aug. 15 and Aug. 30. In treatment initiated later than above, longer the low temperature treatment the earlier the clove differentiation and bulbing in both Southern and Northern strains. The earlier the initiation date and the longer of low temperature treatment, the earlier bolting in southern strain. In Northern strain, bolting was most enhanced in 45 and 60 days of low temperature treatment initiated on Aug. 15 and Aug. 30. The longer the low temperature treatment in plantings thereafter, the earlier the bolting. The earlier the planting date garlic bulbs. Harvest date was earliest in 45 and 60 days low temperature treatment started from July 31 to Aug. 30 in Southern strain, and it was in 60 and 90 days low temperature treatment initiated from July 31 to Aug. 30 in Northern strain. Bulb weight was heaviest in 45 days low temperature treatment of Oct. 14 planting and next was in 45 days treatment of Sep. 29 planting in Southern strain. In Northern strain, bulb weight was heaviest in 60 days treatment of Oct. 14 planting and next was in 45 days treatment of Oct. 14 planting. When considered in the aspect of the beginning date of low temperature treatment, bulb weight was heaviest in 45 days treatment started on Aug. 30 in Southern strain and in 60 days treatment started on Aug. 15 in Northern strain. A high negative correlation between days to harvest and plant height on January 12, and a high positive correlation between days to harvest and days clove differentiation were observed. This indicates that enhanced plant growth and clove differentiation induced by low temperature treatment advanced the harvest date. A high negative correlation between bulb weight and days to clove differentiation, days to harvest suggests that the enhanced clove differentiation result and in heavier bulb weight. From the above results, it suggested that early crop of garlic can be harvested by planting at the period of Sep. 29 to Oct. 14 after 45 days of low temperature treatment of seed bulbs of Southern strain. Then harvest date can be shortened by 30 days compared to control and garlic can be harvested in early April.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.148-156
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• 2010

S59-4 isolate was evaluated as a potential biocontrol agent using in vivo wounded garlic bulb assay. When the spore suspension ($10^5$ spores/$m\ell$) of Penicillium hirsutum was co-inoculated with cell suspension of S59-4 isolate on wounded garlics, the isolate showed high suppressive effect to disease development. The isolate was identified as Pantoea agglomerans S59-4(Pa59-4) through Biolog system. Furthermore, soaking garlic bulbs in the suspension of Pa59-4 significantly reduced garlic decay caused by P. hirsutum. The optimal concentration of Pa59-4 for controlling garlic blue mold was $10^7\sim10^8$ cfu/$m\ell$. And suppressive effect of Pa59-4 on garlic storage decay reduced as inoculation concentration of Penicillium hirsutum increased. In addition in order to investigate population dynamics of Pa59-4 on application site of garlic cloves, two antibiotic markers, pimaricin and vancomycin were selected. Bacterial density of Pa59-4 on the wounded garlic cloves increased continuously both under room temperature condition and low temperature condition until 30days after application of Pa59-4, meanwhile that of Pa59-4 on intact garlic cloves increased until 15days after application of Pa59-4 and thereafter decreased continuously. Two culture media for mass-production of Pa59-4, LB medium and TSB medium, were selected. By-product of bio-fungicide formulated by mixing white carbon and bacterial suspension of Pa59-4 suppressed by 40 to 50% garlic blue mold. Above results suggest that Pa59-4 be a promising control agent against garlic blue mold.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.883-890
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• 2015

The soilborne fungus Fusarium oxysporum f. sp. lilii (Fol) is a serious threat to all lily cultivars, especially infecting bulbs and flowers. It has become increasingly important to develop varieties resistant against the bulb rot disease. Genetic diversity of cultivars and reliable screening methods are required for this purpose. Here, an efficient in vitro screening system for evaluating resistance to Fol in 38 in vitro-grown lily plants was investigated. Various factors including culture conditions of Fol, inoculum density, appropriate plant materials, inoculation method and duration, and incubation period of plant materials after inoculation were combined to optimize the screening method. As a result, we suggest optimal conditions for an in vitro screening system for the selection of Fol-resistant lily cultivars as follows. Fol was grown on potato dextrose agar (PDA) medium for 6 days at $25^{\circ}C$ in darkness and used as working inoculation. Spore suspensions were prepared (inoculum density: $1.0{\times}10^4$ $spores{\cdot}mL^{-1}$), and then leaf segments $1.5{\times}2.0cm^2$ were inoculated by dipping for 22 hours at $25^{\circ}C$ in dark. Later, leaves were cultured on 0.6% agar plates at $25^{\circ}C$ and 50% humidity with a photoperiod of 16 hours light/8 hours dark (fluence rate of $40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) to examine the progress of bulb rot. After 7 days, disease levels were classified into indices 1 (no symptom) to 6 (serious bulb rot). Soil inoculation of Fol carried out with resistant or susceptible lily cultivars that had been selected through in vitro screening confirmed the reproducibility of results. Therefore, the in vitro screening method established in this study is efficient and reliable for selection of lily cultivars resistant against bulb rot disease.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.484-489
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• 2017

Lilies as cut flowers are one of the most popular ornamental plants in South Korea. It is necessary to develop lily cultivars with high qualities. Therefore, highly efficient propagation systems are needed following release of elite cultivars. In this study, we used taurine treatment to improve the growth conditions including shoot and bulb formation, fresh weight gain, and reduction of rooting and browning. We experimentally evaluated the effect of taurine as a growth stimulator, at concentrations of 0, 2.5, 5, 10, 15 and 20 mg/l. The results showed that 20 mg of taurine enhanced shoot formation by 85% and increased fresh weight 5.5-fold, which was higher than the approximately four-fold increase in the control. In addition, multiple bulb formation rate was increased by 80% and rooting by 82% following exposure to 20 mg/l of taurine. The efficiency of taurine treatment was higher than that of control with 50% multiple bulb formation rate and 60% rooting rate. The browning was 10.6% at 2.5 mg/l of taurine when compared with 0.8% at 20 mg/l. Taurine showed a positive effect on the overall growth of lily plants in terms of increased fresh weight, shoot formation rate, rooting, and formation of multiple bulbs, indicating that taurine can be used as an alternative to amino acids or as an antioxidant such as citrate and vitamin C in plant tissue culture.

• The Korean Journal of Pesticide Science
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• v.13 no.3
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• pp.148-158
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• 2009

We tested and selected some agrochemicals reducing the occurrence of major pests and diseases during garlic storage. Tebuconazole, diphenylamine and prochloraz as fungicides and dimethate as a insecticide were sprayed or drenched before harvest. And the harvested garlic was dipped in each of the agrochemicals. The residues of pesticides in garlic bulbs treated were analyzed every month from harvesting time for 6 months. In case of Danyang garlic, which was treated with pesticides before and after harvesting, the residues of diphenylamine, tebuconazole, prochloraz, and dimethoate ranged from 0.008 to 0.28, from 0.03 to 0.32, from 0.02 to 0.12, and from 0.02 to 0.25 mg/kg, respectively. In case of Uiseong garlic, the residues of diphenylamine, tebuconazole, prochloraz and dimethoate ranged from 0.008 to 0.09, from 0.08 to 0.45, from 0.02 to 0.57, and from 0.04 to 0.38 mg/kg, respectively. And, in case of Namdo garlic, the residues of diphenylamine, tebuconazole, prochloraz, and dimethoate ranged from 0.008 to 0.52, from 0.07 to 1.67, from 0.02 to 0.17, and from 0.03 to 0.73 mg/kg, respectively. Some of the garlic samples treated with tebuconazole exceeded its maximum residue limits (MRLs) of 0.1 mg/kg set by Korea Food Drug Administration (KFDA), but dimethoate was detected below its MRL of 1.0 mg/kg. In case of diphenylamine and prochloraz, their MRLs for garlic were not set. Adapting their MRLs, 5.0 mg/kg of diphenylamine for apple and pear and 0.5 mg/kg of prochloraz for strawberry and grape, residue levels of diphenylamine and procloraz were below than their MRLs, with the exception of samples two times treated with procloraz in Namdo garlic. These results indicate that dimethoate can be used as an agrochemical to control the postharvest disease in garlic in only MRL aspect.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.121-130
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• 1985

The phenolic compounds identified from rye and wheat residues seemed to be p-coumaric, p-hydroxybenzoic, vanillic, ferulic, salicylic and syringic acids. Total phenol content of rye and wheat straw determined at heading stage was 0.1803% and 0.1702%, respectively. Total phenol content in straw was higher than that of root at all growth stages. The germination and growth of plants, such as Oryza sativa, Echinochloa creugalli, Cyperus serotinus, Portulaca oleacea, Amaranthus retroflexus, Digitaria saguinalis, and C. album were inhibited by treatments of authentic phenolic compounds as the concentrations increased. However, at the early stage, the germination and shoot growth of P. distinctus were markedly stimulated by them, and then the further growth of shoot and root was markedly inhibited by the prolonged treatment of phenolic compounds. The aqueous extracts from rye and wheat straw completely inhibited the germination of A. retroflexus and C. album at a high concentrations. The content of starch and protein in bulbs of P. distinctus was lower in the p-hydroxybenzoic acid treated plot, at $10^{-2}M$, than the untreated control.

• Journal of Korean Elementary Science Education
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• v.24 no.3
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• pp.259-267
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• 2005

This study was to investigate the elementary students' preconception on the brightness of electric bulb and degree of consistency on their preconceptions. Participants were 160 students of fifth graders in Seoul area. They had already teamed about the brightness of series circuit and parallel circuit of batteries. After they solved six problems in the same context, we provided them a pair of circuit which was an anomalous situation. And then they conducted CCLT (Cognitive Conflict Level Test). Elementary school students showed various preconceptions when they explained the light of bulb of two Simple electric Circuits. Many Students Consistently Showed the Scientific misconceptions like 'the light of bulb of two simple electric circuits was that the more batteries and the fewer bulbs were brighter.' The level of consistency that students presented scientific misconceptions was grouped all of four, such as 'high, middle, low, and nothing.' Therefore the higher scientific achievement they have, the higher consistency they have. As the students had high consistency level, they revealed high cognitive conflict level significantly. This high consistency will help them to change their preconception on the brightness of electric bulb and their cognitive conflict.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.102-108
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• 2006

It is very important to improve fertilizer use efficiency for the saving of fertilizers and for environmental purposes as well. However, there was no effective ways for the fertilization in the mid of growth under the plastic film mulching cultivation so far. For this, a Band Spotty Fertilization (BSF) machine was developed recently. So, we tried to establish a low input fertilization technique using this BSF machine in the vinyl mulching cultivation of onion (Allium cepa L.). Fertilization efficiency, soil properties, and crop yield were examined and compared among treatments from 2000 to 2001. The content of exchangeable K in soils were higher after fertilization but that of available $P_2O_5$ was lower than before the experiment in all plots. The content of nitrate-N was highest at the early growth stage, and higher in BSF plots than that of conventional fertilization (CF). BSF plot showed higher growth rate, and uptake amount of nitrogen of onion by 59-69% than that of CF. N use efficiency in BSF was higher in the order of two time-split application, one time-split application, and three time application. K use efficiency was high 13-17% BSF plots than that in CF($63kg\;ha^{-1}$) plots. The amount of residual N in soils was high by 8-14% in BSF plots compared to that in CF plots, and the loss of N was lowered 26-34% by BSF. Also, the amount of residual K in soils was high by 13-18% and the loss of K was low by 29-31% in BSF plots compared to that in CF plots. The yield of onions increased by 7-13% by BSF due to increased diameter and weight of bulbs. As the results, N fertilization efficiency increased by 22-42% by BSF.

• The Korean Journal of Mycology
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• v.36 no.2
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• pp.153-162
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• 2008

Pinewood nematode (PWN) trapping by nematophagous fungi, Arthrobotrys conoides, A. dactyloides and A. oligospora and the fungal growth were characterized. The three Arthrobotrys species each was inoculated into the PWN cultured on Botrytis cinera fungal colony on potato dextrose agar (PDA). The effects of temperature, pH, PWN inoculation density and nutrients on the growth of the three Arthrobotrys spp were measured. A. conoides grew fast, 13.9 mm/day while A. dactyloides grew slow, 3 mm/day. PDA medium was the best for the fungal growth at $25^{\circ}C$ and pH 4.5. The Arthrobotrys spp growth was stimulated by 500 nematodes inoculation but not by 1000 inoculation. A. dactyloides did not grow below pH 4.5 and at high PWN density. A. conoides and A oligospora formed trapping organs with thick constricting hyphal network only when PWN present, while A. dactyloides formed the organ with circular hyphae constitutively. A. conoides formed trapping organs faster than A. oligospora did. The nematode trapping hyphae of the fungi penetrated into PNW inside to form many tiny infection bulbs and to digest the nematode. However, A. dactyloides formed a few trapping organs but no trapping was observed. Infection rate of PWN was 95% by A. conoides, 80% by A. oligospora and 92% by the combination inoculation of A. conoides and A. oligospora. In contrast A. dactyloides increased PWN density without infecton. There was no interaction effect in any combination inoculation of the three Arthrobotrys spp. A. conoides enhanced PWN infection rate by rapid hyphal growth and early trapping, while A. oligospora did it by increasing hyphal density. In conclusion A. conoides is the most effective in both hyphal growth and infection, and thus these characteristics can be utilized as a biological control of PWN.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.766-773
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• 2013

A transparent film was fabricated based on bacterial cellulose (BC), BC has excellent physical strength and stability at high temperature and it is an environmental friendly flexible material. In order to improve the conductivity, silver nanowire (AgNW) and/or graphene were introduced to the BC membrane. The aspect ratio of the AgNW synthesized in this study was 214, with a length of $15{\mu}m$ and width of 70 nm. The higher aspect ratio improved the conductivity by reducing the contact resistance. The thermal and electrical properties of 7 types of films prepared were investigated. Each film was fabricated with rectangular shape ($2mm{\times}2mm{\times}50{\mu}m$). The films were scored with a net shape by a knife, and filled with AgNW and graphene to bestow conductivity. The film filled with AgNW showed favorable electrical characteristics with a thickness of $350{\mu}m$, electron concentration of $1.53{\times}10^{19}$, electron mobility of $6.63{\times}10^5$, and resistivity of 0.28. The film filled with graphene had a thickness of $360{\mu}m$, electron concentration of $7.74{\times}10^{17}$, electron mobility of 0.17, and resistivity of 4.78. The transmittances at 550 nm were 98.1% and 80.9%, respectively. All the films were able to light LEDs bulbs although their brightness differed. A thermal stability test of the BC and PET films at $150{\pm}5^{\circ}C$ showed that the BC film was more stable, whereas the PET film was quickly banded. From these results, it was confirmed that there it is possible to fabricate new transparent conductivity films based on BC.