• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.229-240
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• 2009

The high temperature and water content in soil profile probably affect the physiological disorder especially on cool-season turfgrasses in warm and humid weather of Korean summer. The purpose of this research was to analyze the effect of soil temperature and water content on the growth and stress response of creeping bentgrass(Agrostis palustris Huds.) under a humid and warm temperature. USGA(United State of Golf Association) green profile in laboratory test, Daily temperature changes were tested under a dried sand, 70% water content of field capacity, and saturated condition at $34^{\circ}C$ of the USGA green in lab. In this test, the dried sand reached to $80^{\circ}C$, however, the surface temperature decrease of $10^{\circ}C$ on the saturated condition. In the thermal properties test in field, thermal conductivity, thermal diffusivity, and soil temperature were increased followed by irrigation practise. In the water-deficient condition, the highest soil temperature was reached temporally right after irrigation, however, the excessive soil water content higher than field water holding capacity showed the highest soil temperature after a while. This result indicated that a heat damage to root system was caused from the thermal conductivity of a high surface soil temperature. The excessive irrigation when a high turf surface temperature should occur a negative result on tufgrass growth, moreover, it would be fatal to root growth of creeping bentgrass, especially when associated with a poor draining system on USGA sand green. Overall, this study shows that high soil temperature with water-excessive condition negatively affects on cool-season grass during the summer season, suggesting that excessive irrigation, over 70% field capacity of soil condition, does not help to reduce soil temperature for summer season in Korea. In the study that cool-season grass were treated with different water content of soil, The soil had higher temperature and more water holding capacity when treatment rate of soil conditioner was increased. The best growth at the normal water condition and the worst state of growth at thee water-excessive condition were observed.

• Journal of Sericultural and Entomological Science
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• v.20 no.2
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• pp.26-31
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• 1978

The objective of the present study was to investigate the effect of nicotine-contaminated mulberry-leaf, which was grown in the vicinity of tobacco drying plant (TDP), on cocoon crop. Mulberry-leaf harvested from the field at Sericultural Experiment Station (SES), Suweon, Korea, was used as control, supposedly nicotine-free leaf. Leaf harvested from the field in the distances of 30-50m, 300-400m and 700-800m from TDP was fed during the whole larval stage of the silkworm at. SES. The effect of leaf in each treatment level on the quantitative characters of the silkworm was summarized as follows; 1. Larval duration from 4th instar on was significantly longer in the TDP-leaf treatments than for the control. 2. Duration of matured silkworm appearance became longer as the distance of the mulberry-field from TDP got shorter, because the larval duration and growth of the silkworm were not uniform in the TDP-leaf treatments. 3. Mortality rates during the late larval, cocoon spinning, and pupal stages were highest for the 30-50m leaf, especially mortality rates during the late larval and pupal stage were serious. 4. Pupation rate was lowest for the 30-50m leaf and those for the 300-400m and the 700-800m leaf were not significantly different from that of the control. 5. Nicotine damage to cocoon weight and cocoon shell weight was significant in each TDP-leaf level. Cocoon shell ratio was reduced at the same extent in each level, compared with the control. 6. The ratio among cocoon-classes was significantly different between treatments, compared with best-cocoon ratio of 87.1% for the control. Cocoons were not uniform for the 30-50m leaf, and those for the 300-400m and the 700-800m leaf were as almost uniform as those for the control. 7. Loss of fresh cocoon yield became greater as the distance of the mulberry-field from the TDP-got shorter. In conclusion, the critical distance of mulberry-field, which influences larval health, cocoon quality and yield, appeared to be 800m from the TDP. Such other factors as wind direction and topographic location may be involved in the critical distance. 8. From the present experiment, we could obtain only the effect of nicotine on the silkworm through digestive system, since the silkworm was raised at SES in Suweon. If the silkworm.. were raised in the vicinity of the TDP, poison effect of nicotine on the silkworm could beo expected through exoskeleton and tracheal system as well as through digestive system.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.717-721
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• 2011

In case of plastic film greenhouses cultivating fresh vegetables on paddy soil, soil characteristics must be considered as more important factor than any other factors. Generally after the four years of cultivation, soils tend to increase electrical conductivity value, nutrient unbalance and soil pests. As a result, degradation of agricultural products occurred, therefore it is necessary to improve soil conditions. In this study, yield and economic cost of cucumber were analyzed. The best soil conditions for cucumber cultivation were alluvial or valley in soil topology, moderately or poorly drainage in soil drainage classes, coarse loamy soil in texture. In addition, rich-sunlight and-deep groundwater would be proper for the cucumber cultivation. Good environmental managements of plastic film greenhouse were as follows. The temperature needed to be adjusted three times. The optimal daytime temperature could be $22{\sim}28^{\circ}C$, the one from 12 until night could be $14{\sim}15^{\circ}C$, and the temperature from 24 to sunrise could be $10{\sim}12^{\circ}C$. During plant growth period, soil moisture content was as low as 10~15%, and it needed to be maintained as 15~20% during reproductive growth period. To control pests, catch crop cultivation and solar treatment were carried out, after those EC was reduced and the root-knot nematode was controled too. Cucumber yield from the plot with improved soil managements increased to $158.4Mg\;ha^{-1}$, but plot with successive cropping injury yielded $140.3Mg\;ha^{-1}$. The income from the plot with improved soil managements was 215,676 thousand won $ha^{-1}$, the plot with successive cropping injury was 131,649 thousand won $ha^{-1}$. Income rate of each plot was 51.8% and 38.4%, respectively.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.197-203
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• 2019

This study was carried out to investigate the effect of chlorine water and plasma gas treatment on the quality and microbial control of Latuca indica L. baby Leaf during storage. Latuca indica L. baby leaves were harvested from a plant height of 10cm. They were sterilized with $100{\mu}L{\cdot}L^{-1}$ chlorine water and plasma-gas (1, 3, and 6hours), and packaged with $1,300cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ films and then stored at $8{\pm}1^{\circ}C$ and RH $85{\pm}5%$ for 25days. During storage, the fresh weight loss of all treatments were less than 1.0%, and the carbon dioxide and oxygen concentrations in packages were 6-8% and 16-17%, respectively for all treatments in the final storage day. The concentration of ethylene in the packages fluctuated between $1-3{\mu}L{\cdot}L^{-1}$ during the storage and the highest concentration of ethylene was observed at 6 hours plasma treatment in the final storage day. The off-odor of all treatments were almost odorless, the treatments of chlorine water and 1 hour plasma maintained the marketable visual quality until the end of storage. Chlorophyll content and Hue angle value measured at the final storage day were similar to those measured before storage in chlorine water and 1 hour of plasma treatments. E. coli was not detected immediately after sterilization in all sterilization treatments. After 6 hours of plasma treatment, the total bacteria fungus counts were lower than the domestic microbial standard for agricultural product in all sterilization treatments. The total aerobic counts in the end storage day increased compared to before storage, whereas E. coli was not detected in all sterilization treatments. The sterilization effect against bacteria and fungi was the best in chlorine water treatment. Plasma treatment showed sterilization effects, but within a prolonged period of time. In addition, the sterilization effect decreased gradually. These results suggest that chlorine water and plasma treatment were effective in maintaining Latuca indica L. baby Leaf commerciality and controlling microorganisms during postharvest storage.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Journal of Life Science
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• v.29 no.5
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• pp.537-544
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• 2019

Genome editing technology employing gene scissors has generated interest in molecular breeding in various fields, and the development of the third-generation gene scissors of the clustered, regularly interspaced short palindromic repeat (CRISPR) system has accelerated the field of molecular breeding through genome editing. In this study, we analyzed the possibility of silkworm molecular breeding using gene scissors by genomic and phenotypic analysis after editing the biogenesis of lysosome-related organelles (BmBLOS) gene of Bakokjam using the CRISPR/Cas9 system. Three types of guide RNAs (gRNA) were synthesized based on the BmBLOS gene sequence of Bakokjam. Complexes of the prepared gRNA and Cas9 protein were formed and introduced into Bombyx mori BM-N cells by electroporation. Analysis of the gene editing efficiency by T7 endonuclease I analysis revealed that the B4N gRNA showed the best efficiency. The silkworm genome was edited by microinjecting the Cas9/B4N gRNA complex into silkworm early embryos and raising the silkworms after hatching. The hatching rate was as low as 18%, but the incidence of mutation was over 40%. In addition, phenotypic changes were observed in about 70% of the G0 generation silkworms. Sequence analysis showed that the BmBLOS gene appeared to be a heterozygote carrying the wild-type and mutation in most individuals, and the genotype of the BmBLOS gene was also different in all individuals. These results suggest that although the possibility of silkworm molecular breeding using the CRISPR/Cas9 system would be very high, continued research on breeding and screening methods will be necessary to improve gene editing efficiency and to obtain homozygotes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.297-306
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• 2021

To select rice (Oryza sativa L.) cultivars suitable for forage-rice double cropping system, the growth and grain quality of four early maturing rice cultivars (Joun, Jopyeong, Haedamssal, and Unkwang), and the chemical properties of soils were investigated under single- (fallow-rice) and forage-rice double-cropping systems in paddy fields in Miryang, southern Korea. The soil where two forage crops [Italian ryegrass (Lolium multiflorum Lam.) and oat (Avena sativa L.)] were cultivated during winter had a slightly lower pH; an increase in total nitrogen (T-N), K, Ca, and Na contents; and a slight decrease in organic matter and available P₂O₅ contents, compared with the soil fallowed during winter. This shows that the chemical properties of paddy soils can be improved by winter forage cropping. At the heading stage, the culm length, panicle length, panicle number, and leaf color of all cultivars, except for Haedamssal, were generally higher under double-cropping than under single-cropping. For Haedamssal, the culm length and leaf color did not differ between the cropping systems, but the panicle length was slightly shortened and its panicle number increased under double-cropping. After harvest, the yield of milled rice decreased for all cultivars except Haedamssal, but increased in Haedamssal under double-cropping. The head rice rate was slightly higher under double cropping, particularly in Jopyeong and Haedamssal, than under single-cropping. The protein content of milled rice under double cropping was higher and its amylose content was similar or slightly lower compared to those of rice under single cropping, resulting in decreased Toyo values for rice under double-cropping. The pasting temperature did not differ significantly between the cropping systems. However, Haedamssal had a low pasting temperature but a high Toyo value under double cropping, compared to the other three cultivars, suggesting that its palatability is relatively high. Furthermore, panicle number increased and milled rice yield did not decrease, even under double cropping. Therefore, Haedamssal seems to be the best cultivar for paddy-based double cropping with forage crops.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.409-415
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• 2022

Plant growth and development are also affected by root-zone environment. Therefore, it is important to consider the variables of the root-zone environment when establishing an irrigation strategy. The purpose of this study is to analyze the relationship between the volumetric moisture content (VWC), Bulk EC (ECb), and Pore EC (ECp) used by plant roots using FDR sensors in two types of rockwool media with different water transmission characteristics, using the method above this was used to establish a method for collecting and correcting available root-zone environmental data. For the experiment, two types of rockwool medium (RW1, RW2) with different physical characteristics were used. The moisture content (MC) and ECb were measured using an FDR sensor, ECp was measured after extracting the residual nutrient solution from the medium using a disposable syringe in the center of the medium at a volumetric moisture content (VWC) of 10-100%. Then, ECb and ECp are measured by supplying nutrient solution having different concentration (distilled water, 0.5-5.0) to two types of media (RW1, RW2) in each volume water content range (0 to 100%). The relationship between ECb and ECp in RW1 and RW2 media is best suited for cubic polynomial. The relationship between ECb and ECp according to volume moisture content (VWC) range showed a large error rate in the low volume moisture content (VWC) range of 10-60%. The correlation between the sensor measured value (ECb) and the ECp used by plant roots according to the volumetric water content (VWC) range was the most suitable for the Paraboloid equation in both media (RW1, RW2). The coefficient of determination the calibration equation for RW1 and RW2 media were 0.936, 0.947, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.4
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• pp.216-224
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• 2023

Since maize (Zea mays L.) originated in central and south America, it requires warm climate conditions throughout its growing season. Growth halts when night-time temperatures drop below 10℃, and the plant may die if temperature reach -1.7℃. Thus, temperature should be maintained between 10 and 30℃ from seeding to maturity. The germination temperature for maize should be at least 8-11℃, whit an optimal range 32-34℃. Since temperature significantly affects the germination rate and period, it plays a crucial role in maize growth. In this study, we evaluated the quantity and feed value of 11 major varieties to determine those best suited for maize cultivation as feed in higher latitude, specifically in Democratic People's of Republic of Korea, below 38 degrees north. A cultivation test was also conducted in Suwon in Republic of Korea, to assess adaptability in areas south of Mt. Suyang. Among the varieties tested, Shinhwangok2 reached silking the fastest, in 65 days, while Gwangpyeongok took the longest at 75 days. The stem length of all varieties exceeded 230 cm. Gwangpyeongok had the tallest stems, while Daanok and Shinhwangok2ho displayed the highest ear ratios. Dacheongok presented the highest values in both dry matter and TDN quantity, with 31,420 kg/ha and 21,66 kg/ha respectively. Pyeonggangok had the highest crude protein content at 8.0%. TDN (%) ranged from 57-68%, with Hwangdaok reaching up to 68%. Based on these findings, Dacheongok and Pyeonggangok appear to be the most suitable varieties for cultivation in terms of both quantity and feed value.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.390-401
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• 2023

Major components of lac coloring include laccaic acids A, B, C, and E. The Korean Food Additive Code regulates the use of lac coloring and prohibits its use in ten types of food products including natural food products. Since no commercial standards are available for laccaic acids A, B, C, and E, a standard for lac pigment itself was used to separate laccaic acids from the lac pigment molecule. A standard for each laccaic acid was then obtained by fractionation. To obtain pure lac pigment for use in food by High performance Liquid Chromatography Photo Diode Array (PDA), a C8 column yielded the best resolution among various tested columns and mobile phases. A qualitative analytical method using High Performance Liquid Chromatography (HPLC) Tandem Mass(LC-MS/MS) was developed. The conditions for fast and precise sample preparation begin with extraction using methanol and 0.3% ammonium phosphate, followed by concentration. The degree of precision observed for the analyses of ham, tomato juice and Red pepper paste was 0.3-13.1% (Relative Standard Deviation (RSD%)), degree of accuracy was 90.3-122.2% with r²=0.999 or above, and recovery rate was 91.6-114.9%. The limit of detection was 0.01-0.15 ㎍/mL, and the limits of quantitation ranged from 0.02 to 0.47 ㎍/mL. Lac pigment was not detected in 117 food products in the 10 food categories for which the use of lac pigment is banned. Multiple laccaic acids were detected in 105 food products in 6 food categories that are allowed to use lac color. Lac pigment concentrations range from 0.08 to 16.67 ㎍/mL.