• 한국기후변화학회지
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• 제9권1호
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• pp.31-45
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• 2018

This study implemented the prediction of drought properties (number of drought events, intensity, duration) using the user-oriented systematical procedures of downscaling climate change scenarios based the multiple global climate models (GCMs), AIMS (APCC Integrated Modeling Solution) program. The drought properties were defined and estimated with Effective Drought Index (EDI). The optimal 10 models among 29 GCMs were selected, by the estimation of the spatial and temporal reproducibility about the five climate change indices related with precipitation. In addition, Simple Quantile Mapping (SQM) as the downscaling technique is much better in describing the observed precipitation events than Spatial Disaggregation Quantile Delta Mapping (SDQDM). Even though the procedure was systematically applied, there are still limitations in describing the observed spatial precipitation properties well due to the offset of spatial variability in multi-model ensemble (MME) analysis. As a result, the farther into the future, the duration and the number of drought generation will be decreased, while the intensity of drought will be increased. Regionally, the drought at the central regions of the Korean Peninsula is expected to be mitigated, while that at the southern regions are expected to be severe.

• 한국작물학회지
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• 제59권2호
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• pp.109-127
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• 2014

Maize is one of the most important food and feed crops in the world including Southeast Asia. In spite of numberous efforts with conventional breeding, the maize productions remain low and the loss of yields by drought and downy mildew are still severe in Asia. Genetic improvement of maize has been performed with molecular marker and genetic engineering. Because maize is one of the most widely studied crop for its own genome and has tremendous diversity and variant, maize is considered as a forefront crop in development and estimation of molecular markers for agricultural useful trait in genetics and breeding. Using QTL (Quantitative Trait Loci) and MAS (Marker Assisted Breeding), molecular breeders are able to accelerate the development of drought tolerance or downy mildew resistance maize genotype. The present paper overviews QTL/MAS approaches towards improvement of maize production against drought and downy mildew. We also discuss here the trends and importance of molecular marker and mapping population in maize breeding.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1412-1412
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• 2003

• 한국농공학회논문집
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• 제62권3호
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• pp.51-61
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• 2020

Drought events are not clear when those start and end compared with other natural disasters. Because drought events have different timing and severity of damage depending on the region, various studies are being conducted using satellite images to identify regional drought occurrence differences. In this study, we investigated the applicability of drought assessment using the Evaporative Stress Index (ESI) based on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images. The ESI is an indicator of agricultural drought that describes anomalies in actual and reference evapotranspiration (ET) ratios that are retrieved using remotely sensed inputs of Land Surface Temperature (LST) and Leaf Area Index (LAI). However, these approaches have a limited spatial resolution when mapping detailed vegetation stress caused by drought, and drought hazard in the actual crop cultivation areas due to the small crop cultivation in South Korea. For these reasons, the development of a drought index that provides detailed higher resolution ESI, a 500 m resolution image is essential to improve the country's drought monitoring capabilities. The newly calculated ESI was verified through the existing 5 km resolution ESI and historical records for drought impacts. This study evaluates the performance of the recently developed 500 m resolution ESI for severe and extreme drought events that occurred in South Korea in 2001, 2009, 2014, and 2017. As a result, the two ES Is showed high correlation and tendency using Receiver Operating Characteristics (ROC) analysis. In addition, it will provide the necessary information on the spatial resolution to evaluate regional drought hazard assessment and and the small-scale cultivation area across South Korea.

• 대기
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• 제31권5호
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• pp.637-656
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• 2021

The United States has been known as the world's major producer of crops such as wheat, corn, and soybeans. Therefore, using meteorological long-term forecast data to project reliable crop yields in the United States is important for planning domestic food policies. The current study is part of an effort to improve the seasonal predictability of regional-scale precipitation across the United States for estimating crop production in the country. For the purpose, a dynamic downscaling method using Weather Research and Forecasting (WRF) model is utilized. The WRF simulation covers the crop-growing period (March to October) during 2000-2020. The initial and lateral boundary conditions of WRF are derived from the Pusan National University Coupled General Circulation Model (PNU CGCM), a participant model of Asia-Pacific Economic Cooperation Climate Center (APCC) Long-Term Multi-Model Ensemble Prediction System. For bias correction of downscaled daily precipitation, empirical quantile mapping (EQM) is applied. The downscaled data set without and with correction are called WRF_UC and WRF_C, respectively. In terms of mean precipitation, the EQM effectively reduces the wet biases over most of the United States and improves the spatial correlation coefficient with observation. The daily precipitation of WRF_C shows the better performance in terms of frequency and extreme precipitation intensity compared to WRF_UC. In addition, WRF_C shows a more reasonable performance in predicting drought frequency according to intensity than WRF_UC.

• 농업과학연구
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• 제38권2호
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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.

• 대한공간정보학회지
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• 제12권4호
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• pp.3-12
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• 2004

농촌지역의 신규 수자원개발과 지속가능한 물의 사용과 배분을 위해서는 수자원의 관리가 매우 중요하다. 본 고는 안성지역을 중심으로 하여 다중 시기의 ETM 위성영상을 이용하여 토양습도를 분석하는 것을 목적으로 한다. Landsat 위성영상은 다목적 실용위성과 융합하여 용수구역도의 배경으로 사용되는 것을 원래 목적이었으나 세 시기에 걸친 영상분석의 결과를 통해 보다 높은 해상도의 토양수분도를 작성할 수 있었다. 2001년 4월의 영상분석결과는 논의 상태는 인공지물과 같이 매우 낮은 반사도 값을 보여준 반면에 5월과 6월에 촬영된 영상의 습도지수는 상당히 높게 나타났으며 이는 이앙기를 지나면서 토양의 습도의 변화를 반영한 것으로 해석된다. 본 연구에서도 산지지역의 경우에는 습윤지수의 변화는 거의 나타나지 않고 있으며 호수와 하천의 경우에는 보유유량에 따라 매우 급격한 변화값을 보여주었다. 위의 결과를 토대로 하여 농업지역의 토양의 습도 상태에 대한 지도제작을 수행하고 가뭄에 민감한 정도가 시간의 변화에 따라 상이한 정도로 표시되는 주제도를 작성할 수 있었다. 이로써 ETM영상과 다목적 실용위성영상의 융합을 통한 습윤지수 지도는 경제적이면서도 빠른 의사결정을 지원할 수 있으며, 수문학적 가뭄과 기후학적 가뭄 자료와 더불어 가뭄 민감도 지도생성을 통한 합리적인 용수 배분에 기여할 수 있을 것으로 사료된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.25-25
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• 2022

Drought becomes frequent and severe because of continuous global warming, leading to a significant loss of crop yield. In soybean (Glycine max [L.]), most of quantitative trait loci (QTLs) analyses for drought tolerance have conducted by investigating yield changes under water-restricted conditions at the reproductive stages. More recently, the necessity of QTL studies to use physiological indices responding to drought at the early growth stages besides the reproductive ones has arisen due to the unpredictable and prevalent occurrence of drought throughout the soybean growing season. In this study, we thus identified QTLs conferring wilting scores and moisture contents of soybean subjected to drought stress in the early vegetative stage using an recombinant inbred line (RIL) population derived from a cross between Taekwang (drought-sensitive) and SS2-2 (drought-tolerant). For the two traits, the same major QTL was located on chromosome 10, accounting for up to 11.5% of phenotypic variance explained with LOD score of 12.5. This QTL overlaps with a reported QTL for the limited transpiration trait in soybean and harbors an ortholog of the Arabidopsis ABA and drought-induced RING-D UF1117 gene. Meanwhile, one of important features of plant drought tolerance is their ability to limit transpiration rates under high vapor pressure deficiency in response to mitigate water loss. However, monitoring their transpiration rates is time-consuming and laborious. Therefore, only a few population-level studies regarding transpiration rates under the drought condition have been reported so far. Via employing an Arduino-based platform, for the reasons addressed, we are measuring and recording total pot weights of soybean plants every hour from the 1^st day after water restriction to the days when the half of the RILs exhibited permanent tissue damage in at least one trifoliate. Gradual decrease in moisture of soil in pots as time passes refers increase in the severity of drought stress. By tracking changes in the total pot weights of soybean plants, we will infer transpiration rates of the mapping parents and their RILs according to different levels of VPD and drought stress. The profile of transpiration rates from different levels of severity in the stresses facilitates a better understanding of relationship between transpiration-related features, such as limited maximum transpiration rates, to water saving performances, as well as those to other drought-responsive phenotypes. Our findings will provide primary insights on drought tolerance mechanisms in soybean and useful resources for improvement of soybean varieties tolerant to drought stress.

• 한국작물학회지
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• 제60권1호
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• pp.8-16
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• 2015

본 연구는 국내 및 해외 유전자원을 이용하여 옥수수 유묘기의 한발 내성 평가를 수행하였다. 1. 약한 한발 환경에서는 장다옥과 청다옥을 제외한 모든 품종에서 2, 3엽의 잎말림 현상을 찾아볼 수 없었다. 장다옥과 청다옥은 첫 번째 잎의 잎말림 현상이 다른 품종에 비해 높게 나타났다. 동남아시아 품종인 DK9955에서도 첫 번째 잎의 잎말림 현상이 나타났으나, 장다옥과 청다옥에 비해 낮은 수준이었다. 2. 심한 한발 환경에서는 대부분의 품종들이 첫 번째 잎에서 3단계 이상의 잎말림 현상을 보였으며, 특히 한국 품종에서 잎말림 현상이 높게 나타났다. 또한, 동남아시아 품종 중 DK9955, Ki3, CML333에서도 첫 번째 잎의 잎말림 현상이 높게 나타났다. 2, 3엽에서는 한국 품종인 광평옥, 다평옥, 장다옥, 청다옥 등이 심한 잎말림을 보였으며, 한발 내성이 약하다고 보고된 Ki3와 B73도 두 번째 잎에서 높은 잎말림 현상이 나타났다. 3. 극심한 한발 환경에서는 모든 품종에서 첫 번째 잎의 잎말림 현상이 높게 나타났다. 대부분의 품종이 세 번째 잎에서는 잎말림 현상이 없었으나, CML247, 다평옥, 장다옥, 청다옥의 경우 3단계 이상의 잎말림이 나타났다. 한발 내성이 강한 것으로 알려져 있는 Ki11과 동남아시아 품종인 LVN10과 LVN99는 극심한 한발 수준에서도 상대적으로 낮은 잎말림 현상이 관찰되었다. 4. 잎말림 회복을 측정한 결과, 2단계 및 3단계의 경우 품종과 엽기에 관계없이 회복 가능하였으나, 4단계 이상의 잎말림 현상이 진행된 경우 회복이 불가하다는 것으로 확인하였다. 5. 종합적으로 토양수분함량 5~7%에서 두 번째와 세 번째 잎의 잎말림 평균이 2.5이하를 보이는 품종들은 유묘기 한발 내성이 강한 것으로 보인다.

• Plant Breeding and Biotechnology
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• 제6권4호
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• pp.354-362
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• 2018

Maize has high food and industrial value, whereas has difficulties in research because of their complex and huge size genome. Nested association mapping (NAM) was constructed to better understand maize genetics. However, most studies were conducted using the reference genome B73, and only a few studies were conducted on tropical maize. Ki3, one of the founder lines of the NAM population, is a tropical maize. We analyzed the genetic characteristics of Ki3 by using RNA sequencing and bioinformatics tools for various genetic studies. As results, a total of 30,526 genes were expressed, and expression profile were constructed. A total of 1,558 genes were differentially expressed in response to drought stress, and 513 contigs of them come from de novo assemblies. In addition, high-density polymorphisms including 464,930 single nucleotide polymorphisms (SNPs), 21,872 multiple nucleotide polymorphisms (MNPs) and 93,313 insertions and deletions (InDels) were found compared to reference genome. Among them, 15.0 % of polymorphisms (87,838) were passed non-synonymous test which could alter amino acid sequences. The variants have 66,550 SNPs, 5,853 MNPs, and 14,801 InDels, also proportion of homozygous type was higher than heterozygous. These variants were found in a total of 15,643 genes. Of these genes, 637 genes were found as differentially expressed genes (DEGs) under drought stress. Our results provide a genome-wide analysis of differentially expressed genes and information of variants on expressed genes of tropical maize under drought stress. Further characterization of these changes in genetic regulation and genetic traits will be of great value for improvement of maize genetics.