• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.377-379
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• 1996

1990이래 단감재배 면적이 확대되고 있는 경주 및 그 인근의 포장으로부터 이미 알려진 병징과는 전혀 다른 병징을 나타내는 병을 단감의 주요 품종인 부유의 이병 잎과 신초로부터 병원균을 분리하고 그 병원 곰팡이의 병원학적 특징을 조사하였다. 이 병은 신초선단부 잎에서 발생하여 아래잎으로 진전되며, 잎에는 잎가장자리나, 중앙부 등 일정한 부위가 없이 발병하여 회갈색의 둥근 무늬가 확대되기도 하고, 심하면 잎이 고사탈락하기도 한다. 심한 경우 병반의 크기가 전체 잎의 1/3이상을 차지할 정도로 크게 확대되었다. 신초는 병의 진전이 심해지면 고사함으로서 나무 생육이 급격히 중지되거나, 나무 수세가 떨어져 수확에도 지장을 주고 있다. 발생시기는 6월 중.하순~7월, 9~10월 초순까지 발병하며, 병든 잎과 가지를 채집하여 병원균을 순수 분리하여 Guba(1949년), Sutton(1969)와 Steyaert(1971)의 분류기준에 따라 동정한 결과는 다음과 같았다. 병원균의 분생포자의 크기는 23.1$\times$7.1 $\mu\textrm{m}$, color cell의 크기와 수는 15.65 $\mu\textrm{m}$, 3개이었고, 포자의 윗부분은 다갈색이었으며 아래부분은 올리브색이었다. Setrlae의 크기와 개수는 23.6 $\mu\textrm{m}$, 2~4(3)개이고, pedicle의 길이는 5.17 $\mu\textrm{m}$였다. 이상의 결과에 근거하여 이 병원균을 Pestalotiopsis theae로 동정하고 국내미기록병으로 보고한다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.464-467
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• 2001

In order to establish a in vitro propagation system for gold tree[Dendropanax morbifera $L_{EV}$], the effects of auxins and cytokinins on shoot multiplication and rooting were investigated. Germination rate was the best in MS medium. The fresh weight and number of shoot were the best on the medium containing 0.1 or 1.0 mg/l BAP and 0.5 or 1.0 mg/l NAA. Shoots were successfully rooted in MS medium with 1.0 mg/l NAA. Roots were easily formed by the addition of auxins, especially 0.1 or 1.0 mg/l BAP.P.

• Asian Journal of Turfgrass Science
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• v.22 no.1
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• pp.25-34
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• 2008

This study was conducted to determine the optimum dose ranges for a mutation breeding based on the observations of a seed germination and an early growth in turfgrasses. Three warm season (Zoysiagrass, Bermudagrass, and Seashore paspalum) and four cool season turfgrasses (Kentucky bluegrass, Tall fescue, Perennial ryegrass, and Creeping bentgrass) were used in this study. We investigated the percentage of a seed germination and a seedling growth after irradiating the turfgrass seeds with various doses of gamma-ray (50, 100, 150, 200, 250, 300, 400, and 500 Gy). After 24 h with a gamma irradiation, the seeds were sown on the wet filter paper in a petri dish and maintained for 3 weeks at 30$^{\circ}C$ for the warm season turfgrasses and at 25$^{\circ}C$ for the cool season turfgrasses. Data on a seed germination and a seedling growth with three replications were collected. The percentage of seed germination was decreased with an increase of the gamma-ray dose. Shoot and root growth, and the fresh weight were decreased significantly as the radiation dose was increased. A radiation dose indicating a 50% growth inhibition ($LD_{50}$) with a gamma irradiation was varied among those turfgrass species used, with the highest at about 500 Gy for bermudagrass and the lowest at 100Gy for tall fescue. The optimum dose for a gamma irradiation for a selection of turfgrass mutants was considered to be about 300, 150, 500, 150, 200, 100 and 200 Gy for zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, and creeping bentgrass, respectively.

• Research in Plant Disease
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• v.21 no.1
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• pp.27-31
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• 2015

In April 2014, Fusarium wilt was found on kohlrabi seedlings in Iksan, Korea. Symptoms included wilting of foliage, drying and withering of older leaves, and stunting of the plants. The infected plants eventually died during growth. Colonies on potato dextrose agar were pinkish white, and felted with cottony and aerial mycelium. Macroconidia were falcate to almost straight, thin walled and usually 3-septate. Microconidia were usually formed abundantly in false-heads on short monophialides on the hyphae and were hyaline, smooth, oval to ellipsoidal, aseptate or medianly 1-septate, very occasionally 2-septate, slightly constricted at the septa, $4-11{\times}2.5-5{\mu}m$. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers (internal transcribed spacer rDNA and translation elongation factor $1{\alpha}$), the fungus was identified as Fusarium oxysporum. Pathogenicity of a representative isolate was proved by artificial inoculation, fulfilling Koch's postulates. To our knowledge, this is the first report on the occurrence of Fusarium oxysporum on kohlrabi in Korea.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.8-14
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• 2011

This study was conducted to investigate the effect of age of transplants, propagated by cutting, of two cut rose (Rosa hybrida Hort.) cultivars on their subsequent growth and yield in an effort to develop an efficient cutting propagation method for domestic rose cultivars. Two cultivars used in this study were a standard type 'Pink Aurora' and a spray type 'Yellow King'. Cuttings were prepared as single node cuttings each with a five-leaflet leaf and were stuck in rockwool cubes ($5cm{\times}5cm{\times}5cm$, UR, Korea) at two different dates. Cuttings rooted for either 30 (stuck on Jan. 20, 2009) or 48 days (stuck on Jan. 2, 2009) were transplanted into a rockwool slabs ($10cm{\times}15cm{\times}100cm$, UR, Korea) on the same date, 18 Feb. 2009. Plant growth and cut flower quality were investigated for two successive harvests during the period of Jan. to July in 2009. In both cultivars, 48 days old plants showed some growth of the shoot and root before transplanting. However, in the case of 30 days old plants before transplanting no noticeable growth of the shoot and root was obserable in 'Pink Aurora', while only shoot growth, but not root growth to the bottom of the rooting medium, was observed in 'Yellow King'. This suggested cultivar-specific responses that in this experiment a spray type 'Yellow King' showed greater growth rate during the rooting stage than a standard type 'Pink Aurora'. In the measurement of growth and cut flower yield after transplanting, the 48 days old standard type 'Pink Aurora' produced greater number of cut flowers per plant than 30 days old plants, whereas their mean stem fresh weight was recorded smaller than that of the 30 days old plants. For 'Yellow King', 30 days old plants showed greater stem length, flower width, number of five-leaflet leaves per stem, stem fresh weight, and number of cut flowers per plant than 48 days old plants. Therefore, growth and yield were significantly affected by cultivar and age of the rooted cutting, and additional research is needed on the effect of age of rooted cuttings in more cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.214-221
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• 2020

Salinity is one of the major abiotic stressors that inhibits the growth, yield, and productivity of crop plants. Therefore, it is necessary to develop crops with increased salt tolerance for cultivation in saline soils such as is found in reclaimed land. The objective of this study was to develop a salt-tolerant silage rice line that grows on reclaimed land. In order to develop this salt-tolerant silage rice, we transferred Saltol, a major QTL associated with salt tolerance, from IR64-Saltol, a salt-tolerant indica variety, into Mogyang, a susceptible elite japonica variety. To determine the effect of salt stress, Mogyang and IR64-Saltol cultivars were grown on a medium containing various concentrations of NaCl in in vitro conditions. Shoot length was found to decrease with increasing salt concentrations, and root growth was almost arrested at NaCl concentrations over 50 mM in the Mogyang cultivar. Based on these preliminary results, we screened five salt-tolerant lines showing superior growth under salt stress conditions. Polymerase chain reaction and sequencing results showed that the introgression types of Saltol QTL were derived from the IR64-Saltol cultivar in almost all selected lines. Based on the observed growth and physiological characteristics, the new Saltol introgression lines showed higher salt tolerance compared to the Mogyang parental cultivar. The salt-tolerant lines identified in this study could be used as a genetic resource to improve rice salt tolerance.

• Journal of Plant Biotechnology
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• v.46 no.1
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• pp.22-31
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• 2019

The objective of this study was to investigate the suitable parts for callus induction and optimal concentrations of growth regulators contained in the medium affecting shooting and rooting Echeveria laui and Echeveria elegans for in vitro mass production. To determine the suitable plant parts for callus induction, the leaves were divided into upper, medium and bottom parts and cultured on MS medium at different concentrations with $0{\sim}2mgL^{-1}\;NAA$ and $0{\sim}4 mgL^{-1}BA$. The upper and middle parts of leaves both showed 100% callus formation rate with $NAA\;1\;mgL^{-1}$ and $BA\;1\;mgL^{-1}$ treatment in E. laui. The middle parts of leaves showed 83.3% callus formation rate at $NAA\;2\;mgL^{-1}$ and BA 4 mgL-1 treatment in E. elegans. The shoot induction rate from callus was highest at $NAA\;0.1\;mgL^{-1}$ and $BA\;3\;mgL^{-1}$ treatment in E. laui and $NAA\;0.3\;mgL^{-1}$ in E. elegans. In addition, the number of shoots formation was 10.4 shoots high in $NAA\;1\;mgL^{-1}$ and $BA\;1\;mgL^{-1}$ treatment in E. laui and 12.0 shoots in most effective $NAA\;1\;mgL^{-1}$ and $BA\;0.1\;mgL^{-1}$ treatment in E. elegans. In the case of acclimatization of regenerated plant, growth characteristics did not show any significant difference (35 ~ 55%) shading with respect to the different ratio of substrate mixture, and it was determined that would be appropriate considered plant height and appearance preference of E. laui and E. elegans. It was established that the optimization of culture condition was responsible for the mass propagation in vitro cultures of E. laui and E. elegans.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.3
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• pp.130-144
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• 2013

In this study, we examined the effect of high temperature of urban area on the physiological response of apple tree including the photosynthesis, shoot growth, and fruit quality of 'Fuji'/M.9 apple trees planted at Daegu urban area (DUA) and Gunwi rural area (GRA) for 2 years (2009-2010). During the apple growing season (April-October), the average air temperature of DUA was about $3.0^{\circ}C$ higher than that of GRA and the total rainfall of DUA was 130 mm more than that of GRA. During fruit enlargement stage (June-August), the number of days that recorded daily mean temperature of over $30^{\circ}C$ were ten on DUA in 2010, but there was no day when such temperature was experienced in 2009. Average air temperature of DUA during the maturation stage (September-October) was $19.8^{\circ}C$, which was $4.0^{\circ}C$ higher than that of GRA. The higher temperature of over $30^{\circ}C$ during fruit enlargement stage decreased the photosynthetic rate, shoot growth, fruit weight, and soluble solid content of 'Fuji'/M.9 apple tree. The moderate temperature of about $20^{\circ}C$ during maturation stage increased the photosynthetic rate and soluble solid content of 'Fuji'/M.9 apple tree, but decreased fruit red color. In regional comparison with GRA, photosynthetic rate of DUA was changed from lower before rainy season to higher after rainy season. Fruit weight was higher in DUA than that of GRA. However, fruit weight between DUA and GRA did not show the difference when accumulated days that recorded daily maximum temperature over $35^{\circ}C$ of DUA was increased. Compared to the GRA, soluble solid content of DUA was higher, but fruit red color of DUA was less. These results indicate that the poor red coloring is the most problematic in 'Fuji'/M.9 apple tree by global warming and urbanization.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.39-51
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• 1984

Effects of major phenolic acids identified from barley residues (straw, root) on the germination of rice and 3 paddy weeds such as Echinochloa crusgalli, Cyperus serotinus, and Potamogeton distintus were evaluated to obtain the basic informations on the development of naturally occurring herbicides. The predominant phenolic compounds extracted from barley residues in both straw and root were identified as p-coumaric, p-hydroxybenzoic, ferulic, vanillic, and salicylic acids by means of paper chromatography. Total phenol content of barley straw and root at the harvesting stage was 0.169% and 0.127% per dry weight, respectively. During the decomposing process, total phenol content slightly increased and then decreased. The germination of test plants was inhibited by treatments of 4 major authentic phenolic acids identified, most significantly on rice, and less on E. crusgalli, and C. serotinus. P. distintus, however, was markedly stimulated by them as the concentration increased, and then sprouted buds of pondweeds were changed to dark brownish color, resulting in the death as the treatment prolonged. The greater inhibitory effect appeared on shoot growth rather than germination. The aqueous extracts of barley residues showed the similar inhibitory effect on the germination and shoot growth of rice and three paddy weeds as the treatments of 4 authentic phenolic acids.

• Journal of Plant Biotechnology
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• v.31 no.1
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• pp.55-60
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• 2004

This experiment was carried out to develop rapid mass propagation via shoot organogenesis system from adventitious roots of Rehmannia glutinosa. The induction of adventitious roots from leaf explants was most favorable to MS solid medium supplemented with 2mg/L IBA. However, the growth of adventitious roots was highest when they were cultured on 1/3 strength MS liquid medium supplemented with 2mg/L IBA. When the adventitious roots were grown in 10L bioreactor, 10g roots as initial inoculum was increased to 225g after 6 weeks of culture. The harvested roots were cultured onto solid medium to induce plant regeneration. The optimal adventitious shoot formation was observed on MS medium supplemented with 2mg/L BA. Rooting of individual shoots was induced after transfer to half strength MS medium without growth regulators. Plantlets after acclimatization were successfully transplanted in the field and no phenotypic variation was observed among them.