• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.366-366
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• 2020

The drought is one of the extreme natural disasters observed in any climate zone and it is due to the deficiency in moisture. The flash drought is identified recently as a subdivision of drought and it is an extreme event distinguished by sudden onset and rapid intensification of drought conditions with severe impacts. The main cause for the flash drought is coupled situation due to precipitation deficit and high evapotranspiration. Hence, heat waves plays major role in identification of flash drought. Therefore, this study focused on identifying changes in distribution of heat waves for Korean Peninsula. The daily maximum and minimum temperature data were used in this study. The heat wave, heat wave intensity and heat wave intensity index were derived. The results of the study would be an input for the future studies on identification of flash drought in Korean Peninsula.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.158-158
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• 2022

Ecological drought consequences have received a lot of attention in recent years. Thus, ecological drought was proposed as a new drought category to characterize the impact of drought on ecosystems. The current study used a unique drought index, the standardized supply-demand water index (SSDI), and a run theory to detect ecological drought occurrences and characteristics such as drought-affected area, drought severity, drought duration, drought frequency, and drought orientation in the Hwang River, an environmentally valuable region. Hence, to assess drought-prone areas, the bivariate probability and return period will be calculated using a two-dimensional joint copula. The core results show that (a) the Spatio-temporal characteristics of ecological drought were successfully recognized using the spatial and temporal identification approach; (b) in comparison to the SPEI meteorological drought index, the SSDI is more credible and can more readily and effectively capture the entire properties of ecological drought information; (c) the Hwang river had seen the most severe drought occurrences between the late 1990s and the mid-2020s, with 48.3 percent occurring before the twenty-first century; (d) Severe ecological drought occurrences occurred more frequently in most areas of the Hwang River (e) Only the drought duration and severity in the Hwang area were more responsive to temperature when temperatures rise around 1.1℃, the average drought duration and severity rise around 16 % and 26 %, respectively. This suggested that the Hwang River has been exposed to more severe heat stress in the twenty-first century. Thereupon droughts in the twenty-first century occurred with bigger affected regions, longer durations, higher frequency, and more intensity.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.552-555
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• 2007

In this study, the MODIS NDVI for the period of $2000{\sim}2007$ was collected and processed to obtain VCI and SVI which are the quantitative indexes of drought. The VCI and SVI based on NDVI can be used for understanding seasonal pattern of vegetation, drought identification and quantitative analysis of drought. VCI and SVI compared with monthly precipitation ratio to average, Standardized Precipitation Index(SPI), and etc., which are used to identify spring drought, to analyze drought region, similarity and difference in drought severity. In addition, frequency of Spring droughts were calculated for the period of $2000{\sim}2007$, and the usability of the MODIS images as a tool for establishing countermeasures against drought was presented by analyzing drought frequently areas.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.29-29
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• 2022

The fast-changing climatic conditions make plants to be vulnerable to many abiotic stresses. Drought stress is one of the limiting factors that affect pepper production in water deficient regions. It affects plant growth and development by altering physiological, morphological, and metabolic processes. Breeding drought tolerant varieties is one of the mitigation strategies to overcome the ever increasing drought disaster. Hence, screening of new drought tolerant pepper genotypes is essential. The current study was aimed to identify new drought tolerant genotypes among the collection of pepper genetic resources. In total, 70 pepper genotypes were screened for drought tolerance after exposure to drought stress condition. The pepper genotypes were classified as highly tolerant, intermediate, or severely sensitive to drought stress based on the phenotypic analysis. Consequently, 13 genotypes significantly exhibited higher recovery rate after drought stress and were classified as highly tolerant. Comparative analysis of morphological and physiological parameters and expression of drought responsive genes between tolerant and susceptible pepper genotypes will be presented and discussed. The identified tolerant genotypes will be useful resources for breeding drought tolerant pepper cultivars.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.153-153
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• 2017

Potato (Solanum tubersosum L.) is susceptible to various environmental stresses such as frost, high temperature, and drought. Enhancement of potato drought tolerance can reduce yield loss under drought that has negative effect on potato tuber growth. Genetic engineering can be utilized to achieve this goal, but such approaches using endogenous potato genes have rarely been applied. Since unpredictable global weather changes cause more severe and frequent water limiting conditions, improvement of potato drought tolerance can minimize such adverse effects under drought and can impact on sustainable potato production. Genetic engineering can be utilized to improve potato drought tolerance, but such approaches using endogenous potato genes have rarely been applied. We were obtained AtbZIP28 gene transgenic potato plants. It is identified transcript levels at various stress conditions, polyethylene glycol (PEG), NaCl, abscisic ${\underline{acid}}$ (ABA). Also, For identification to regulate ER stress response genes in AtbZIP28 gene transgenic potato plant, we screened seven potato genes from RNA-seq analysis under TM treatment. Five and two genes were up- and down-regulated by TM, respectively. Their expression patterns were re-examined at stress agents known to elicit TM, DTT, DMSO and salt stress.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.13-26
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• 2021

Recent drought events in the South Korea and the magnitude of drought losses indicate the continuing vulnerability of the agricultural drought. Various studies have been performed on drought hazard assessment at the regional scales, but until recently, drought management has been response oriented with little attention to mitigation and preparedness. A vulnerability assessment is introduced in order to preemptively respond to agricultural drought and to predict the occurrence of drought. This paper presents a method for spatial, Geographic Information Systems-based assessment of agricultural drought vulnerability in South Korea. It was hypothesized that the key 14 items that define agricultural drought vulnerability were meteorological, agricultural reservoir, social, and adaptability factors. Also, this study is to analyze agricultural drought vulnerability by comparing vulnerability assessment according to weighting method. The weight of the evaluation elements is expressed through the Analytic Hierarchy Process (AHP), which includes subjective elements such as surveys, and the Entropy method using attribute information of the evaluation items. The agricultural drought vulnerability map was created through development of a numerical weighting scheme to evaluate the drought potential of the classes within each factor. This vulnerability assessment is calculated the vulnerability index based on the weight, and analyze the vulnerable map from 2015 to 2019. The identification of agricultural drought vulnerability is an essential step in addressing the issue of drought vulnerability in the South Korea and can lead to mitigation-oriented drought management and supports government policymaking.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.3
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• pp.237-241
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• 2017

Drought is one of the detrimental factors that impair plant growth and productivity. In this study, we applied annealing control primer (ACP)-based reverse transcriptase PCR (polymerase chain reaction) technique to identify differentially expressed genes (DEGs) in maize leaves in response to drought stress. Two-week-old maize seedlings were exposed to drought (DT) by suspending water supply. DEGs were screened after 3 days of DT-treated samples using the ACP-based technique. Several DEGs encoding 16.9 protein, antimicrobial protein, hypothetical protein NCLIV_068840, thioredoxin M-type were identified in maize leaves under drought stress. These genes have putative functions in plant defense response, growth and development. These identified genes would be useful for predictive markers of plant defense, and growth responses under drought stress in plants.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.10a
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• pp.179-179
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• 2018

Potato (Solanum tubersosum L.) is susceptible to various environmental stresses such as salt, high temperature, and drought. Especially, potato tuber growth is greatly affected by drought that causes not only yield reduction but also loss of tuber quality. Since unpredictable global weather changes cause more severe and frequent water limiting conditions, improvement of potato drought tolerance can minimize such adverse effects under drought and can impact on sustainable potato production. Genetic engineering can be utilized to improve potato drought tolerance, but such approaches using endogenous potato genes have rarely been applied. We were obtained AtbZIP28 gene transgenic potato plants. It is identified transcript levels at various stress conditions, polyethylene glycol (PEG), NaCl, (ABA). Also, For identification to regulate ER stress response genes in AtbZIP28 gene transgenic potato plant, we screened seven potato genes from RNA-seq analysis under TM treatment. Five and two genes were up- and down-regulated by TM, respectively. Their expression patterns were re-examined at stress agents known to elicit TM, DTT, DMSO and salt stress.

• Journal of Korea Water Resources Association
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• v.51 no.6
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• pp.471-479
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• 2018

This study analyzed the peak time of drought severity and drought period using meteorological and hydrological drought indices. Standardized Precipitation Index (SPI) using rainfall data was used for meteorological drought and Streamflow Drought Index (SDI) and Standardized Streamflow Index (SSI) using streamflow data were used for the hydrological drought. This study was applied to the Cheongmicheon watershed which is a mixture area for rural and urban regions. The rainfall data period used in this study is 32.5 years (January of 1985~June of 2017) and the corresponding streamflow was simulated using SWAT. After the drought indices were calculated using the collected data, the characteristics of drought were analyzed by time series distribution of the calculated drought indices. Based on the results of the this study, it can be seen that hydrological drought occurs after meteorological drought. The difference between SDI and SPI peak occurrence time, difference in drought start date and average drought duration is greater than SSI and SPI. In general, SSI shows more severe than SDI. Therefore, various drought indices should be used at the identification of drought characteristics.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.199-204
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• 2011

This study was conducted to map quantitative trait loci (QTLs) related to drought stress tolerance. An introgression line population derived from a cross, "Ilpum" / "Moroberekan" was used in this study. $F_1$ plants were backcrossed three times to Ilpum to produce $BC_3F_1$ plants. These plants were advanced by selfing for four generation and a total of 117 $BC_3F_5$ introgression lines were developed. These lines were evaluated for percent seed set and spikelets per panicle under the control (field) and drought condition. To identify QTLs related to drought tolerance, 134 SSR markers showing polymorph isms between the parents were genotyped for the 117 $BC_3F_5$ lines. A total of 6 QTLs associated with drought stress were detected on chromosomes 1, 3, 4, 7 and 10. These include two QTLs for phenotypic acceptability, two QTLs for percent seed set ($R^2$ = 19.0 - 20.9%), and two QTLs for spikelets per panicle ($R^2$ = 22.3 - 23.10%). The Moroberekan alleles at three loci contributed the positive effect for drought tolerance. The SSR markers linked to drought stress tolerance can not only facilitate the selection of valuable genes from Moroberekan, but also allow identification of lines with drought tolerance.