• Development and Reproduction
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• v.16 no.2
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• pp.87-93
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• 2012

Reproductive biology (maturation and spawning) of the female tongue sole Cynoglssus semilaevis were examined in 154 specimens caught from the west coast of Korea (between February and November 2010). Monthly changes of gonadosomatic index (GSI) and condition factor (CF) were peaked in September. Hepatosomatic index (HSI) showed a negative correlation with those of the GSI. Ovaries were classified into six stages based on the development of advanced oocyte and histological characteristics: virgin/immature, early developing, developing, late developing, ripe/spawning and spent/regressing stage. The relationship between fecundity (F) and total length (TL) of the fish was expressed as $F=251.43TL^{0.1264}$, and body weight (BW) was expressed as F=1130.4BW-880848. Biological minimum size of female was 46.87 cm (TL).

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.159-159
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• 2017

Drought, a common environmental constraint, induces a range of physiological, biochemical and molecular changes in plants, and can cause severe reductions in crop yield. Consequently, understanding the molecular mechanisms of drought tolerance is an important step towards crop biotechnology. Here, we report that the rice (Oryza sativa) homeodomain-leucine zipper class IV transcription factor gene, ${\underline{R}ice}$ ${\underline{o}utermost}$ ${\underline{c}ell-specific}$ gene 10 (Roc10), enhances drought tolerance and grain yield by increasing lignin accumulation in ground tissues. Overexpression of Roc10 in rice significantly increased drought tolerance at the vegetative stages of growth and promoted both more effective photosynthesis and a reduction in water loss rate, compared with non-transgenic controls or RNAi transgenic plants. Importantly, Roc10 overexpressing plants had a higher drought tolerance at the reproductive stage of growth and a higher grain yield compared with the controls under field-drought conditions. Roc10 is mainly expressed in outer cell layers including the epidermis and the vasculature of the shoots, which coincides with areas of cell wall lignification. Roc10 overexpression elevated the expression levels of lignin biosynthetic genes in shoots, with a concomitant increase in the accumulation of lignin, while the overexpression and RNAi lines showed opposite patterns of lignin accumulation. We identified downstream target genes of Roc10 by performing RNA-seq and chromatin immunoprecipitation (ChIP)-seq analyses of shoot tissues. Roc10 was found to directly bind to the promoter of PEROXIDASEN/PEROXIDASE38, a key gene in lignin biosynthesis. Together, our findings suggest that Roc10 confers drought stress tolerance by promoting lignin biosynthesis in ground tissues.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.104-104
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• 2017

Sorghum (Sorghum bicolor (L.) Moench.) is one of the most important crops for human and animal nutrition. Nonetheless, sorghum has a cyanogenic glucoside compound which can be degraded into hydrogen cyanide, toxic to humans and animals even with tiny amount. In consequence, breeding materials with a low cyanide level has been a top priority in sorghum breeding programs. To fulfill our long-term goal, we are screening sorghum accessions with low cyanide level, which would be an important breeding material for food safety. We collected seeds of various sorghum accessions and analyzed relevant metabolites to find useful breeding materials of sorghum accessions containing low cyanide. Fourteen wild relatives were obtained from the University of Georgia in US, a reference accession BTx623, and three local varieties from National Agrobiodiversity Center of Rural Development Administration in Korea, and one wild species from the Wild Plant Resources Seed Bank of Korea University in Korea. Sorghum plants were grown in plastic greenhouse under natural conditions. After growing, leaf samples were harvested at different developmental stages: seedling phase, vegetative phase (right before flowering), and reproductive phase (ripening). Using collected samples, quantification analysis were performed by an HPLC system for three metabolites (dhurrin, 4-hydroxybenzaldehyde, and 4-hydroxyphenylacetic acid) in sorghum plants. Prior to metabolome analysis, specific experimental condition for HPLC system was set to be able to separate three metabolites simultaneously. Under this condition, these metabolites were quantified in each accession by HPLC system. We observed that the metabolite contents were changed differently by developmental stages and accessions. We clustered these results into five groups as patterns of their contents by developmental stages. Most of accessions showed that 4-hydroxybenzaldehyde content was very high at seedling stage and decreased rapidly at vegetative phase. Interestingly, the patterns of dhurrin content were very different among clusters. However, 4-hydroxyphenylacetic acid content was maintained at low levels by developmental stages in most accessions. The results would demonstrate how dhurrin and alternative degradation pathways are differentiated in each accession.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.299-299
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• 2017

Due to the climate changes in Korea, the numbers of both torrential rain events and drought periods have increased in frequency. Water management practice against water shortage and flooding is one of the key interesting for field crop cultivation, and groundwater often serves as an important and safe source of water to crops. Therefore, the objective of this study is to evaluate the effect of groundwater table levels on soil water content and soybean development under two different textured soils. The experiment was conducted using lysimeter located in Miryang, Korea. Two types of soils (sandy-loam and silty-loam) were used with three groundwater table levels (0.2, 0.4, 0.6m). Mean soil water content during the soybean growth period was significantly influenced by groundwater table levels. With the continuous groundwater level at 0.2m from the soil surface, soil water content was not statistically changed between vegetative and reproductive stage, but the 0.4 and 0.6m groundwater table level was significantly decreased. Lower chlorophyll content in soybean leaves was found in shallow water table treatment in earlier part of the growing season, but the chlorophyll contents were non-significant among water table treatments. Groundwater table level treatments were significantly influenced on plant available nitrogen content in surface soil. The highest N contents were observed in 0.6m groundwater table level. It is probably due to the nitrogen loss by denitrification as the result of high soil water content. The length and dry weight of primary root was influenced by groundwater level and thus the highest length and dry weight of root were observed in 0.6m water table level. This result showed that soybean root growth did not extend below the groundwater level and increased with the depth of groundwater table level. The results of this study show that the management of groundwater level can influence on soil characteristics, especially on soil water content, and it is an important practice of to reduce yield loss caused by the water stress during the crop growing season.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.433-439
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• 2020

This study, which was designed to improve and increase the utilization of female elk, examined the possibility of collecting their embryos during the non-reproductive period using ultrasound-guided Ovum Pick-Up (OPU) technology. Once follicles in the ovaries of an elk were observed, the embryos were retrieved through the absorption of the follicles using an OPU ultrasound probe. Fifty-seven embryos were retrieved from 85 follicles, giving a retrieval rate of 67.1%. Morphological evaluation of the recovered embryos revealed 14.0% embryos to be in grade A, 19.2% in grade B, 15.7% in grade C, and 50.8% in grade D. The developmental efficiency of the retrieved embryos was also investigated using in vitro maturation, in vitro fertilization, and in vitro culture. After cultivating 28 embryos through in vitro fertilization, 19 embryos were found to be fertilized; the fertilization rate was 67.9%. Four embryos developed to the blastocyst stage, indicating a 14.3% development rate. This study confirmed that the production of fertilized embryos from a seasonal breeder, such as elk, is possible via the ultrasound-guided OPU method. If the efficiency of in vitro fertilization and in vitro culture can be improved through further research, it will help improve the efficiency of elk embryo production through the transplantation of their fertilized embryos.

• Reproductive and Developmental Biology
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• v.32 no.3
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• pp.175-181
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• 2008

This study was conducted to investigate an effective recipient oocyte and culture system for producing of Hanwoo (Korean native cattle) somatic cell nuclear transfer (SCNT) embryos. Hanwoo ear skin fibroblasts were used as donor cells. In vitro matured Hanwoo or Holstein oocytes were enucleated, and single donor cells were transferred into the perivitelline space of the enucleated oocytes. The couplets were subsequently fused and activated. The reconstructed embryos were cultured in a conventional or sequential culture system. In the former, embryos were cultured in CR2aa medium for eight days; in the latter, embryos were cultured in modified CR2aa-A (mCR2-A) for three days and then further cultured in modified CR2aa-B (mCR2-B) for five days. In the experiment with the recipient oocyte, the rate of embryo development to the blastocyst stage was significantly (p<0.05) higher in Hanwoo recipient oocytes than in Holstein ones (48.8% vs 38.9%). BIastocysts derived from Hanwoo recipient oocytes contained significantly (p<0.05) higher numbers of total cells than those derived from Holstein recipient oocytes ($156.0{\pm}68.2$ vs $134.7{\pm}54.8$). There was no difference in the mean proportion of apoptotic cells in blastocysts between the sources of recipient oocytes. In the experiment with the embryo culture system, the blastocyst rate was somewhat higher in sequential system than in conventional system (50.0% vs 43.5%), though there was no significant difference. The numbers of total ($160.0{\pm}69.0$ vs $156.7{\pm}68.4$) and apoptotic cells ($14.0{\pm}10.4$ vs $11.8{\pm}6.4$) were not different between the culture systems. In conclusion, the present study demonstrated that Hanwoo recipient oocytes and the sequential culture system were more effective in supporting the production of Hanwoo SCNT embryos.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.1
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• pp.9-15
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• 2000

The objective of this study is to evaluate the use of RADARSAT and Landsat TM data for the monitoring of rice growth. The relationships between backscatter coefficients($\sigma$$^{0}$ ) of RADARSAT data and digital numbers (DN) of Landsat TM and rice growth parameters were investigated. Radar backscatter coefficients were calculated by calibration process and then compared with rice growth parameters; plant height, leaf area index (LAI), and fresh and dry biomass. When radar backscatter coefficient ($\sigma$$^{0}$ ) of rice was expressed as a function of time, it is shown that the increasing trend ranged from -22--20dB to -9--8dB as growth advances. The temporal variation of backscatter coefficient was significant to interpret rice growth. According to the relationship between leaf area index and backscatter coefficient, backscatter coefficient underestimated leaf area index at the beginning of life history and overestimated, at the reproductive stage. The same increasing trend between biomass and backscatter coefficient was shown. From these results, RADARSAT data appear positive to the monitoring of rice growth. Each band of time-series Landsat TM data had a significant trend as a rice crop grows during its life cycle. Spectral indices, NDVI[(TM4-TM3)/(TM4+TM3)] and RVI(TM4/TM2), derived from Landsat TM equivalent bands had the same trend as leaf area index.

• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.102-108
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• 2003

This experiment was conducted to evaluate the diversity and purity of the Korean ginseng (Panax gjnseng) lines developed by the pure line selection using RAPD markers. Four primer (OPA 19, OPM 11, URP 3 and UBC 98) out of the 48 primer tested produced band which showed within-line polymorphisms at least in one line. Within-line polymorphisms were detected in six lines by OPA 19, in four lines by URP 03, in five lines by OPM 11, and in one line by UBC 98 respectively. Five plants obtained from the commercial cultivar 'Cheonpung' were differentiated using the primers OPA 19 and OPM 11. Five plants obtained from the 'Yeonpung were differentiated using the primer OPM 11. Detection of within-line RAPD polymorphisms might be attributed to the fact that cross pollination appear in P. gjnseng and a long period of three to four years required to reach the reproductive stage thereby delay the process to homozygosity.

• Development and Reproduction
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• v.3 no.1
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• pp.101-105
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• 1999

N-Methylpurine-DNA glycosylase (MPG) removes N-methylpurine and other damaged purines in DNA. RT-PCR analysis revealed MPG mRNA expression at various tissues of fetal development from day 8 to day 18 fetus and day 400 mature adult. The MPG transcripts were abundant during fetal development in mice. In placenta, the MPG mRNA was continuously decreased from day 8 post coitum (p.c) to day 18 p.c. fetus. The high level of mRNA in fetal brain and liver was drastically declined in day 400 mature adult. The expression of MPG, originally characterized by its highest level of expression in the epididymis of adult mouse, was detected with high level in several other reproductive organ, including the ovary, oviduct, testis, vas deference, uterus, and seminal vesicles. These results demonstrate developmental stage- and tissue-specific variation of MPG gene expression.

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.59-64
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• 2006

This study was conducted to establish a convenient freezing method of boar semen. Boar semen was cooled until $5^{\circ}C$ for 3 hrs using cell freezer and loaded into straws. Semen straws were frozen in different steps in strofoam box filled with $LN_2$. Highest sperm viability (54.0%) was obtained by 1-step freezing(holding at 10 cm height from the surface of $LN_2$ for 10 min). Sperm viability increased by holding at $-102^{\circ}C$ for 10min (74.0%, P<0.05). In thawing regime, sperm viability was significantly higher in $37^{\circ}C$ group than in $52^{\circ}C$ group. The sperm characteristics did not differ between 1-step and 3-step. After IVF using frozen-thawed boar semen, developmental rate of embryos to the morula+blastocyst stage was in 1-step freezing group than that of 3-step freezing group (27.5 vs 14.7%, P<0.05). The result shows that the 1-step freezing with holding at $-102^{\circ}C$ for 10min before plunging into $LN_2$ is a convenient and easy freezing method for boar semen.