• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.3
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• pp.195-200
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• 2002

Research trends of papers published in Journal of the Korean Society of Grassland Science(JKSGS) during last 20 years(1982~2001) were examined. Total number of papers published in JKSGS during last 20 years was 668. In the classification of published papers according to research objects, the rate of paper related to grassland was highest as average 18.6% of total research papers during last 20 years. Next was an orchardgrass 8.7, com 8.4, and sorghum and sorghum $\times$ sudangrass hybrid 7.1%. In classification of published papers according to research fields, cultivation field was studied more than others and the rate of cultivation field was highest as 38.8%, and physiology, utilization, breeding and biotechnology field was 23.7, 20.7, 9.1 and 6.6%, respectively. In comparison of average rate of research contents on the papers published during last 20 years, studies on the manure and fertilization were continously increased up to average 20% during recent 5 years(1997~2001). Study on the biotechnolgy was rapidly increased from average 6.6% of last 20 years to average 15% of recent 5 years. Study on the weed was also increased from average 2.5% to 5.9%. On the other hand, studies on the productivity and quality were rapidly decreased from average 31.3% of 5 years(1982~1956) to average 7.7% of recent 5 years. Research trend on the pasture appeared to be similar.

• Horticultural Science & Technology
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• v.18 no.4
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• pp.518-522
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• 2000

The objective of this research was to determine the effect of waste nutrient solution (WNS) on growth and development of poinsettia 'Gutbier V-10 Amy'. To achieve this, WNS collected from rose grown in greenhouse was diluted with various times and 500 mL of each solution was applied every week. Then growth characteristics and nutrient uptake were determined at 180 days after transplanting. The treatment of undiluted WNS had highest plant height and length of branch among treatments tested, but there were no statistical differences in the number of bract and branches. Undiluted WNS had higher leaf number, leaf length, leaf width, fresh weight, and dry weight than any other treatments tested. There was also a trend that increased dilution times of WNS resulted in decreased plant growth. Undiluted WNS had higher chlorophyll content than Hyponex treatment, but diameter of crown did not show significant differences among treatments. In the analysis of root media collected at 6 months after fertilization, the treatment of undiluted WNS had higher electrical conductivity and organic matter content than other treatments, but the Hyponex treatment had higher phosphorus concentration than other treatments tested.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.215-222
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• 2016

Triploidy was induced in the marine medaka, Oryzias dancena by cold shock treatment ($0^{\circ}C$) of fertilized eggs for 30, 45, or 60 min, applied two minutes after fertilization. The triploid genotype was induced by each of the thermal shock regimes tested. The best result was obtained when the eggs were treated for 45 min, which induced triploidy in all the resulting fish. Triploidy was confirmed using chromosomal and flow cytometer analyses, and erythrocyte measurements. The surface areas and volumes of the erythrocytes of triploid fish were significantly larger than those of diploid fish, and their chromosome number (3N=72) was 1.5 times greater that for the diploids (2N=48). Based on a flow cytometer analysis, the triploid fish had approximately 1.5 times the cellular DNA content (2.40 pg/cell) of the diploid specimens (1.61 pg/cell). Data from this study provide the basis for the development of unique models for studying reproductive confinement in transgenic fish.

• Journal of Aquaculture
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• v.18 no.2
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• pp.115-121
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• 2005

This study was performed to investigate the formation and mass production of resting eggs by freshwater rotifer, Brachionus calyciflorus as influenced by different aeration supplements and exchange intervals of culture water in 15-L culture vessels and 500 L culture tanks. The maximum densities and mixis rates of the rotifers were not different between experimental group exposed to air or oxygen supplements. However, the fertilization rate and formation of resting eggs of the rotifers in the air-supplemented group were significantly higher than those in the oxygen supplemented group. In the experiment concerning exchange interval of culture water, the maximum density of the rotifers and formation of resting eggs in the batch culture were significantly higher than those in the semi-continuous culture with exchange of water every day. The formation of resting eggs per Chlorella dry weight was highest in the semi-continuous culture with exchange of water every day. The resting eggs of rotifers were produced at a density of $51.8{\sim}57.9{\times}10^6$ eggs in 500-L culture tanks. In this study, the batch culture with air is an effective method for mass production of resting eggs by the freshwater rotifer, B. calyciflorus, and the efficiency of mass production of resting eggs by this rotifer was similar to that of the seawater rotifers, B. plicatilis and B. rotundiformis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.446-451
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• 2019

This study investigated the application of artificial insemination and pregnancy diagnosis kit for Korean native black goats. Semen was collected by electrical ejaculation, followed by semen analysis and artificial insemination in three goat strains (Dangjin, Jangsu and Tongyoung). Pregnancy was confirmed using a cow pregnancy test kit (IDEXX Rapid Visual Pregnancy Test kit) and ultrasound diagnosis. Analysis revealed that semen collected from male Korean native black goats by electrical ejaculation was about 1~1.5 ml in volume, $18{\sim}25{\times}10^8/ml$ concentration, and having > 97% motility. Furthermore, confirmation of pregnancy by pregnancy test kit and ultrasound diagnosis after artificial insemination were similar. In addition, the efficiency of pregnancy was 20~40% for all three strains: Tongyoung was the highest with 44%, followed by Dangjin (%), and Jangsu (20%). This study determines the artificial fertilization efficiency and the feasibility of using a cow pregnancy test kit for early pregnancy diagnosis in Korean native black goats. Although further research is required for validation, the results of the current study contribute to the breeding and improvement of Korean native black goat in research institutions as well as in general farms.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.133-139
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• 1999

This study was carried out to investigate in vitro/in vivo development of vitrified-thawed immature mouse oocytes. Immature mouse oocytes were vitrified with EFS40 (40% ethylene glycol, 18% ficoll and 0.5 M sucrose). Thawed oocytes were matured for 16 hr in vitro. Matured oocytes with the first polar body were fertilized with the concentration of 1~2$\times$10$^{6}$ $m\ell$ of epididymal sperm. After fertilization, cleavage ($\geq$ 2-cell) and in vitro/in vivo development rates were examined. $\pi$ Ie results were summarized as follows: in vitro maturation rate of immature mouse oocytes in vitrified-thawed group was similar to that in exposed group (67.5%) and control (66.3%), but cleavage rate of vitrified-thawed oocytes (64.9 %) and blastocyst formation rate (59.0%) were significantly different compared to those of exposed group (83.7 and 74.7%) and control (90.7 and 83.7%) (p＜0.05). However, when the blastocysts derived from immature mouse oocytes vitrified-thawed were transferred to pseudopregnant mouse, total implantation (31.3%) was slightly lower than that in control (40.8%), but live fetus formation rate (66.7%)was slightly higher than that in control (58.1%), there was not significantly different. Therefore, when the blastocyts produced in vitro were transferred into recipients, although the development in vitro of oocytes vitrified-thawed was decreased, live fetus formation rate was similar to that of control group. The present results indicate that immature mouse oocytes can be frozen successfully by vitrification with EFS40.

• Journal of Aquaculture
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• v.7 no.4
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• pp.189-205
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• 1994

Formerly, adult-tiger puffer, Takifugu rubripes with ova caught in the sea, were used for seedling production. But it was difficult to secure naturally-ripened adults. For the purpose of adult tiger puffer in captivity, this study was carried out. To determine the growth 220 tiger puffers hatched in 1990 (3-year-old) and 1991 (2-year-old) were used. For spawning and egg incubation leading to fry development, eggs were stripped from tiger puffers hatched in 1988 (5-year-old) and 1990 (3-year-old) through human chorionic gonadotropin (BCG) treatments. In May, 1993, mean body length and mean body weight of 2-year-old tiger puffer were $30.72\pm1.35cm\;and\;1,048\pm228 g,$ and that of 3-year-old tiger puffers were $36.02\pm1.17cm$ and $1,402\pm66g$ respectively. The relationship between body length (L) and body weight (W) of 2-year-old the tiger puffers during the experiment period was represented as $W\;=\;1.7892L^{31524}\times10^5$ (r= 0.9436) and that of 3-year-old, $W=\;3.2840L^{36099}\times10^6$ (r= 0.9070) respectively. The GSI in female 2-year-old-fish changed from $0.23\times0.l2\;to\;0.74\pm0.08$, during the experiment period, and in male it didn't change remarkably until November, but thereafter it increased and showed a peak of $8.69\pm5.09$. The GSI of 3-year-old-fish showed a peak of $8.05\pm5.58$ in April in female and $12.65\pm4.60$ in May in male. The change of HSI in 3-year-old-fish was correlative to the change of GSI, but in 2-year-old-fish it was little correlative. In female gonad of 2-year-old tiger puffer, the mature oocytes reached $350{\mu}m$ in April, but thereafter they didn't spawn and became atrophied. But in male gonad, a great number of spermatozoa were crowded in the testicular lobuli in April. Female gonad of 3-year-old tiger puffer had the mature oocytes of 650 pm in March and the ripe oocytes, $900{\mu}m$ in April. Male testis development was similar to that of 2-year-old-fish. Egg-stripping after hormone treatments was possible past 139 hours and 142 hours from each of two 5-year-old-fish (500IU/kg, BW), and after 114 hour from a 3-year-old-fish (1,000 IU/kg, BW) under water temperature $16.3\~17.8^{\circ}C$. Eggs stripped amounted was 650 g and 400 g from two 5-year-old-fish and 610 g from the 3-year-old-fish, and fertilization rates were $98.0\%,\;97.4\%\;and\;96.5\%$ respectively. All the hatched larvae devloped into normal fry.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.378-383
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• 2001

Embryo culture, ovule culture and ovary slice culture were tested to find optimum method for overcoming post fertilization barrier in interspecific crosses between L. longiflorum 'Gelria' and L. cernuum. Although reciprocal crosses between the species were carried out by cut-style pollination method, fruits developed only in crosses of L. longiflorum${\times}$L. cernuum. On the 40 days after pollination, ovaries were sliced into 2-4mm thickness and cultured on a hormone-free Murashige-Skoog (MS) medium, supplemented with 2%, 4%, 6%, 8% and 10% sucrose. For the L. longiflorum Gelria'${\times}$L. cernuum cross, ovule development was found to be best at 6% sucrose and a lot of hybrid plant lets established directly from the ovary slice culture and subsequent ovule culture. High concentration of sucrose above 8% made ovules abort or vitrificate from 40 days after culture. In contrast, ovules from the L. cernuum${\times}$L. longiflorum 'Gelria' cross swelled well in ovary slice culture, however, they did not germinated in subsequent ovule culture. On the 60 days after pollination, ovules thicker than 0.6mm was interpreted as one containing embryo. The embryo size ranged from 1.2 mm to 1.7 mm, and in vitro development of the excised embryos was found to be best with the MS medium (pH 5.8), supplemented with $0.1-1 mg{\cdot}L^{-1}$ NAA and 6% sucrose. Thick ovules excised 60 days after pollination germinated about 60% as normal seeds in MS medium supplemented with 6% sucrose and free hormone. The ovule culture 60 days after pollination was concluded to be most recommendable to produce interspecific hybrids in large scale crosses between L. longiflorum 'Gelria' and L. cernuum by the reason of easy procedure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.275-283
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• 2010

This experiment was conducted to construct process models to estimate grain weight (GW) and grain nitrogen content (GN) in rice. A model was developed to describe the dynamic pattern of GW and GN during grain-filling period considering their relationships with temperature, solar radiation and growth traits such as LAI, shoot dry-weight, shoot nitrogen content, grain number during grain filling. Firstly, maximum grain weight (GWmax) and maximum grain nitrogen content (GNmax) equation was formulated in relation to Accumulated effective temperature (AET) ${\times}$ Accumulated radiation (AR) using boundary line analysis. Secondly, GW and GN equation were created by relating the difference between GW and GWmax and the difference between GN and GNmax, respectively, with growth traits. Considering the statistics such as coefficient of determination and relative root mean square of error and number of predictor variables, appropriate models for GW and GN were selected. Model for GW includes GWmax determined by AET ${\times}$ AR, shoot dry weight and grain number per unit land area as predictor variables while model for GN includes GNmax determined by AET ${\times}$ AR, shoot N content and grain number per unit land area. These models could explain the variations of GW and GN caused not only by variations of temperature and solar radiation but also by variations of growth traits due to different sowing date, nitrogen fertilization amount and row spacing with relatively high accuracy.

• Applied Biological Chemistry
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• v.9
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• pp.125-147
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• 1968

This experiment was carried out as a part of the studies on reasonable application of nitrogen in rice plant to determine: (I) Nitrogen absorption. and rooting of rice seedlings as affected by urea foliar application at late seedling stage (II) Effect of leaf prunning and foliar application of urea at late heading stage on the maturation and yield of rice (III) Effect of foliar application of urea and its time during the stage of ear formation on yield of rice plant. Results obtained are summarized as follows. Exp.I: Nitrogen absorption and rooting of rice seedlings as affected be urea foliar application at late seedling stage. 1 : The foliar application of urea plots$(T_{1},T_2)$ snowed mare N-content than non-urea foliar application plot(T0) at lane seedling stage, being significant among treatments and foliar application of urea seemed more effective in increasing the N-content of seedlings. and promoted root settlement and early growth alter the transplanting. 2 : The carbon contents of the plants of $T_1$, and $T_2$ at late seedling stage increased than T0, and the carbon contents. of $T_1$ and $T_2$ plots became higher in amount in proportion to the nitrogen absorption as compared with those of $T_0$. 3 : C/N ratio appeared significant among soil application plots($N_1, \;N_2$) and foliar application of urea plots ($T_1$, $T_2$ and $T_0$). C/N ratio was lower in case of increased amount of nitrogen. The higher contents of nitrogen and carbon and lower C/N ratio resulted in the increment of root numbers and root lengths. Exp.II: Effect of leaf prunning and foliar application of urea at late heading stage on the maturation and yield of rice. 1 : There was a highly significant decrease in the maturing rate by severe leaf prunning. In the mean time, significant increase in maturing rate was observed with urea foliar application and it was found the more frequent application the more effective for higher maturing rate with a moderate significance. A correlationship between the level of prunning and maturing rate was enumerated to 0.961 of correlation coefficient, which indicated an increased maturing rate by the increased number of remaining leaves. 2 : The 1.000 grain weight, grain weight and hulled rice yield increased by leaf prunning in order (plot a$A_1$, $A_3$, $A_2$ and $A_0$ were 89.8%, 89.4%, 87.8% and 87.5% respectively, showing the highest of rate in $A_1$ and $A_3$ in methods of ear fertilization and being highly significant between its treatment. 3 : 1000 grain weights were highly significant between time of application, showing a tendency of increase of weights with the time lagging until days before earings as that of maturing rates. High significance was recognized between methods of ear fertilization, showing the highest in $A_2$ 23.18 gr. 4 : Yields per $3.3m^2$ were not significant between time of ear fertilization, whereas were highly significant between methods of ear fertilization. Those of $A_1$, $A_3$, $A_2$ and $A_0$ were 1.486 kg, 1.491 kg, 1.381 kg and 1.328 kg, respectively, showing the highest in $A_1$ and $A_3$. 5 : Hulling ratios showed significant different between time of ear fertilization, showing the highest in $T_2$, whereas those of methods of ear fertilization were highly significant between its treatment, Those of $A_1$, $A_3$, $A_2$ and $A_0$ were 84.72%, 84.06%, 83.29%, and 82.56% respectively, showing the highest m $A_2$ and $A_3$ among others. 6 : Yields of hulled rice per $3.3m^2$ showed significant different between time of ear fertilization, showing the highest in $T_1$ 1.192 kg. Whereas, those were highly significant between methods of ear fertilization. Those of $A_1$, $A_3$, $A_2$ and $A_0$ were 1.259 kg, 1.254 kg, 1.149 kg and 1.095 kg, respectively, showing the highest in $A_1$ and $A_2$. 7 : Contents of nitrogen on rice plant increased in case of nitrogen application as ear fertilizer and showed that the case of urea foliar application was more effective than that of soil application, showing the increased nitrogen content of rice plant was accompanied by carbon content.