• Horticultural Science & Technology
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• v.35 no.2
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• pp.252-264
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• 2017

Tea is one of the most consumed beverages worldwide and the relatively high levels polyphenols is benefit for health. In this study, we developed an efficient system for proliferation of callus from 'Anji Baicha', a cultivar of tea (Camellia sinensis). Callus tissue was initially induced by culturing leaf explants on medium containing different plant growth regulators. For callus induction, thidiazuron (TDZ) was more effective than 2,4-dichlorophenoxyacetic acid (2,4-D), ${\alpha}-naphthalene$ acetic acid (NAA), and $N^6-benzyladenine$ (BA). The frequency of callus induction from leaf explants reached 90.21% on $1.0mg{\cdot}L^{-1}$ TDZ and the developed callus was reddish and friable. We also tested the effect of different concentrations of NAA, 2,4-D, indole 3-acetic acid (IAA), BA, and TDZ, alone and in combinations, on callus proliferation. Medium supplemented with TDZ in combination with IAA was suitable for callus proliferation and accumulation of tea polyphenols. The growth index value and tea polyphenol content of callus cultured on MS medium containing $0.5mg{\cdot}L^{-1}$ TDZ and $1.0mg{\cdot}L^{-1}$ IAA was maximally 1,351% and 23.24%, respectively, and the relative abundance of epicatechin was as high as 17.449%. We also measured the antioxidant activity of all samples and the callus with the highest tea polyphenol content also exhibited high potential radical scavenging activity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.306-311
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• 2010

The multiplication and movement of Xanthomonas oryzae pv. oryzae in rice leaves of seven near-isogenic lines(NILs) derived from different genetic sources and from the susceptible cultivar Toyonishiki were examined. The bacterium populations increased rapidly in susceptible cultivar leaves of the inoculation sites but increased gradually in NIL leaves. X oryzae pv. oryzae were detected at 20cm above the leaves of the inoculated sites in IRBB 103 and Toyonishiki but were not detected in the other NILs at 25 days after inoculation. These results support that resistant genes restrict bacterial movement not multiplication.

• Journal of Crop Science and Biotechnology
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• v.10 no.4
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• pp.281-286
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• 2007

Gibberellins are growth hormones that play a pivotal role in the growth and development of plants. Present investigations were carried to check the effect of nitrogen(N) and silicon(Si) on bioactive $GA_1$ and its immediate precursor $GA_{20}$ at different growth stages of two rice cultivars with different maturity traits. It was observed that the endogenous bioactive $GA_1$ level gradually increased during vegetative stage and anthesis stage of both Junghwabyeo(early flowering cultivar) and Daesanbyeo(late flowering cultivar). However, the $GA_1$ and $GA_{20}$ content start decreasing during the seed filling stage in both rice cultivars, which indicated a possible relationship of bioactive $GA_1$ and floral development. Our results also confirmed that early 13-hydroxylation pathway was operated at all developmental stages of rice plant. Variation in the levels of the endogenous gibberellins in rice shoots were measured by GCMS-SIM using $^2H_2$-labeled gibberellins as internal standards. Combined application of N and Si enhanced growth parameters and reduced lodging index of both rice cultivars. It was thus concluded that the level of physiologically active $GA_1$ increased during vegetative and early reproductive stage, but starts declining at seed filling stage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.307-314
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• 1996

An experiment was carried out to determine effect of cultivar and preservative on the characteristics and quality of baled oat(Avena sativa L.) hay after 60 days of storage. Ihe main plots consisted of the cultivars such as 'Foothill' and 'Swan', and the subplots consisted of preservatives such as commercial propionic acid(CA), lactic bacteria inoculant(LB) and control(C0). Bale temperature of 'Foothill' oat hay maintained higher than that of 'Swan' oat hay during storage. Bale temperature of oat hay treated with CA remained lowest during the earlier storage period and no significant difference was found among preservatives during the latter storage period. Visual assessment of bale of 'Swan' oat hay was better in the evaluation of mold, odor and color than that of 'Foothill' oat hay after storage. DM content of Foothill oat hay increased markedly than that of 'Swan' oat hay through the storage period. CFU(Colony fodng unit) of total viable micmrganism of oat hay bales was not quite different between preservatives, but that of lactic bacteria of 'Swan' oat hay and 'Foothill' was different by over 16 and lo4, respectively. Total nitrogen content of 'Swan' and 'Foothill' oat hay was 1.45 and 2.22%, respectively(P<0.05) and effect of preservatives on total N content was higher in the order of LB, CA, and CO. ADIN content of 'Swan' was lower than that of 'Foothill'(P

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.407-414
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• 2021

This study investigated on the chemical components, quality characteristics, antioxidant compounds, and activity of maize hybrids according to the cultivar, and breeding maize seeds crossed with seed and pollen parent. The moisture, crude fat, crude ash, crude protein, carbohydrate, and amylose contents of maize hybrids were significantly different among cultivars, and seeded and pollinated maize. The L-, a- and b-value of maize hybrids were 39.81~47.21, -0.01~0.55 and 5.85~18.47, respectively. Water binding capacity, water solubility index and swelling power were 123.29~153.32, 4.69~5.76 and 20.11~21.47%, respectively. The phenolic compounds and radical scavenging activity of maize hybrids were significantly different among cultivars, and seeded and pollinated maize. Total polyphenol and flavonoid contents of maize hybrids were 1,335.41~1,876.29 ㎍/g and 184.24~453.95 ㎍ CE/g, respectively. The DPPH and ABTS radical scavenging activities were 171.75~239.16 and 299.44~364.09 mg TE/100 g, respectively. As a result, it could be used as a basic data for cultivating phenol compounds and antioxidant activity in maize breeding.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.63-70
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• 2021

Two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) is one of the major pests in apple orchards. TSSM was known to show different population dynamics depending on apple cultivars. We tested the host plant preference and fitness of TSSM on the leaves of 3 apple cultivars, Fuji, Tsugaru, and Hongro. TSSM showed higher behavioral preference to Fuji than Tsugaru and Hongro, and showed a higher fecundity in Fuji. The immature development of this mite was the shortest in Fuji and longest in Hongro. Total fecundities were not significantly different among cultivars, but daily fecundity was higher and longevity was lower in Fuji. Hongro was the less preferred cultivar for TSSM, and showed the lowest fitness by life table parameters. These results could explain the possible mechanisms of differential population dynamics among apple cultivars. Further study including diverse apple cultivars currently available in Korea could help to deploy time- and cultivar- specific IPM tactics.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.375-382
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• 2021

For stable cultivation in double cropping, it is important to use potato (Solanum tuberosum L.) cultivars with a short dormancy period of 50-70 days and plant seed tubers of appropriate type and size. An experiment was conducted during 2018-2019 to investigate the effects of seed tuber type and size on growth and yield performance in double cropping. Whole tubers of three sizes (10-20 g, 30-40 g, and 50-60 g) and conventional cut tubers weighing 30-40 g from three cultivars with different dormancy periods, namely 'Daeji' (40-60 days), 'Eunsun' (50-60 days), and 'Saebong' (50-80 days), were planted, and their field performance was compared. Regardless of the cultivar, the increase in the whole tuber weight up to 30-40 g led to fast emergence, thereby increasing ground cover rate, shoot growth rate, and tuber growth rate, which ultimately improved tuber yield by 33-54%. Comparing the whole and cut tubers, 'Daeji' and 'Eunsun' showed similar growth and yield performance; as such, the performance of whole tubers weighing 10-20 g was comparable to that of cut tubers weighing 30-40 g. However, 'Saebong', a cultivar with relatively long dormancy period, performed better with cut tuber than with whole tubers. Based on these results, we recommend the use of whole tubers weighing over 30 g for double cropping. Further studies to break tuber dormancy are warranted in cultivars with relatively long dormancy periods (50-80 days), such as 'Saebong'.

• Journal of Mushroom
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• v.14 no.3
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• pp.94-99
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• 2016

To breed a new Korean Pleurotus eryngii cultivar with high quality and yield, single crosses between $24{\times}46$ and KNR2539 were performed, and a new cultivar, $6{\times}13$, was selected based on the days to harvest (14.6 days), quality (7.2), and yield (85.9 g/850 cc bottle). The strain was named Aeryni 5 and cultivated on a large scale at the mushroom farms to compare with Keuneutari 2ho. The yield of Aeryni 5 (82.2 g) was 122.7% of Keuneutari 2ho, and the quality of the new cultivar was 7.7 while reference cultivar was 6.3. The yield and quality of the two cultivars were statistically different. The lightness of the pileus of Aeryni 5 (61.7) was greater than that of Keuneutari 2ho by 3.4 points; thus, the pileus of Aeryni 5 looked brighter. PCR with URP2 was used to discriminate between Aeryni 5 and Kenneutari 2ho.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.21-26
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• 2010

Microbial-fermented tea (MFT), which is made by microorganisms through fermentation, is a popular beverage in Asia, especially in the Yunnam province, China. In this study, changes of the chemical constituents and antioxidant activity during the manufacturing process of MFT were investigated. MFT were respectively prepared from fresh leaves of three different tea species (Yabukita, Daecha, and Korean wild cultivar) and a processed green tea (Korean wild cultivar). The color of the tea infusions gradually changed to red and yellow as a function of fermentation time. Total nitrogen and caffeine contents were not significantly changed. Whereas, the chlorophyll, tannin, and total catechins contents gradually decreased. Interestingly, the epicatechin and epigallocatechin contents increased up to 25 days of fermentation and then decreased. Change of the chemical constituents of all samples showed the same patterns. The antioxidant activity of MFT from Daecha and Yabukita slightly decreased as increasing fermentation time. However, the range over which the antioxidant activity of MFT from Korean wild cultivar and green tea were not changed. This research suggests that it may be possible to manufacturing possibility of MFT using Korean wild cultivar and processed green tea.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.719-722
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• 2011

The Daecha-12 and Yabukita varieties of powdered green teas were grown under 85% shade-cultivated condition, and their physicochemical properties were analyzed. Total catechin content was not significantly different but, non-gallated catechin content in Daecha-12 was significantly higher than that in Yabukita. Theanine (32%), caffeine (14%), lutein (15%) and total chlorophyll (28%) levels were significantly higher in Daecha-12 than those in Yabukita. The results of a color analysis showed that the lightness L-value of Yabukita was higher than that of Daecha-12 but, that the greenness negative a-value and b-values of Daecha-12 were higher than those of Yabukita. The Daecha-12 cultivar had lower catechin content but higher content of theanine, caffeine, theobromine, lutein, chlorophyll, and a negative a-value than those of the Yabukita cultivar. Thus, the Daecha-12 cultivar is suitable to prepare a high-quality powdered green tea product.