• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.301-308
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• 2005

This study was carried out to investigate the effect of stem-cutting (SC) length and portion on the major agronomic characters related with dry matter production and accumulation, and to examine their relation­ships in cassava. When cassava was planted with longer SCs or with older portion SCs, major canopy or source characters like leaf number and leaf area index developed excessively, while tuber yields could be reduced due to the decrease of root/shoot ratio, relative growth rate, root dry weight, and harvest index, particularly in the bitter varieties (high cyanide-level varieties). It was considered that the sweet varieties (low cyanide-level varieties) be early­bulked with higher tuber yield when they are planted with the 25-30 cm long SCs or with the SCs from young type to semi-mature portions of mother stems, while the bitter varieties with the 15-20 cm long SCs or with the SCs from semi-mature to hardwood portions of mother stems, respectively. However, a significant interaction between length and portion of SC was not observed in all agronomic characters.

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.159-160
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• 2008

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.205-214
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• 2008

Blast disease caused by the fungal pathogen, Magnaporthe oryzae, is one of the most damaging diseases in rice. The use of resistant varieties is an effective measure to control the disease, however, many resistant varieties were broken down to their resistance effects by the differentiating of new virulent isolates. This study was done to analyze the haplotypes of 31 microsatellite markers linked to five major R genes and two QTLs and to identify the alleles for the putatively novel genes related to durable resistance to blast in 56 Korean japonica and four indica varieties. The 31 microsatellite markers produced 2 to 13 alleles(mean = 5.4) and had PICi values ranging from 0.065 to 0.860(mean=0.563) among the 60 rice accessions. Cluster analysis based on allele diversities of 31 microsatellite markers grouped into 60 haplotypes and ten major clusters in 0.810 genetic similarity. A subcluster IV-1 grouped of early flowering varieties harboring Piz and/or Pi9(t) on chromosome 6 and Pita/Pita-2 gene on chromosome 12. The other subcluster V-1 consisted of four stable resistance varieties Donghae, Seomjin, Palgong and Milyang20. The analysis of putative QTLs associated with seven blast resistance genes using ANOVA and linear regression showed high significance to blast resistance across regions and isolates in the markers of two genes Piz and/or Pi9(t) and Pita/Pita-2. These results illustrate the utility of microsatellite markers to identify rice varieties is likely carrying the same R genes and QTLs and rice lines with potentially novel resistant gene.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.64.2-64
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• 2003

Twenty-seven monogenic rice lines harboring major resistant gene for blast were screened to analyze their resistance spectrum to Korean blast fungus population using 190 isolates collected from 1985 to 2002. Especially, the monogenic line containing Pi-9 gene was screened using 320 isolates. Based on the monogenic lines-blast isolate interactions, the 27 rice lines were classified into 9 groups. The chinese rice cultivar LTH showed susceptible to all the tested isolates. Those lines IRBLz-Fu, ERBL5-M and IRBL9-W harboring Pi-z, Pi-5, and Pi-9, respectively showed broader spectrum of resistance than those rice lines having Pi-19, Pi-7 etc. Interestingly, the Pi-9 gene(IRBL9-W) showed resistance to most isolates collected before 2000, but it showed susceptible reactions to 5％ and 20％ of blast fungus population in 2001 and 2002, respectively. Population of virulent isolates to Pi-ta, Pi-b, and Pi-7 also were increased in 2002 compared to those before 2000.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.04a
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• pp.125-125
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• 2022

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.10a
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• pp.188-188
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• 2017

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.10a
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• pp.237-237
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• 2021

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.1
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• pp.25-37
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• 2024

As the agricultural land use shifts from paddy to upland, ensuring reservoir water supply stability for upland crop irrigation becomes essential. The objectives of this study were to estimate the irrigation water requirements considering the upland irrigation scenario and to evaluate the reliability of the water supply from the agricultural reservoir using resilience indexes. Two study sites, Sinheung and Hwajeong, were selected, and soybean and red peppers, the most water-intensive crops, were selected as study crops, respectively. For the irrigation scenario, two irrigation methods of traditional scheduling (which irrigates all sites at once) and rotational scheduling (which distributes irrigation by districts), along with the upland conversion rate, were considered. The net irrigation requirement was estimated through a water balance analysis. The stability of the reservoir was evaluated using resilience indexes based on the simulated 10-years reservoir water levels and drought criterion. Overall, the water supply of the reservoir was evaluated as stable during the simulated 10 years, except for the one year. Compared to the two irrigation methods, rotational scheduling resulted in lower irrigation water usage in both sites, with reductions of 1.6%, and 0.3%, respectively. As the upland conversion rate increases, the water deficit could be intensified in Hwajeong with a conversion rate exceeding 50%, showing the number of deficit(ND) over the one and a rapid increase in the deficit ratio(DR). It was confirmed that the reservoir operation criteria can be enhanced by incorporating resilience indicators along with crop growth information, thus, this will be a further study.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.92-92
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• 2017

Bakanae disease is one of the most serious and oldest problems of rice production, which was first described in 1828 in Japan. This disease has also been identified in Asia, Africa, North America, and Italy. Germinating rice seeds in seed boxes for mechanical transplantation has caused many problems associated with diseases, including bakanae disease. Bakanae disease has become a serious problem in the breeding of hybrid rice, which involves the increased use of raising plants in seed beds. The indica rice variety Shingwang was selected as resistant donor to bakanae disease. One hundred sixty nine NILs, YR28297 ($BC_6F_4$) generated by five backcrosses of Shingwang with the genetic background of susceptible japonica variety, Ilpum were used for QTL analysis. Rice bakanae disease pathogen, CF283, was mainly used in this study and inoculation and evaluation of bakanae disease was performed with the method of the large-scale screening method developed by Kim et al. (2014). SSR markers evenly distributed in the entire rice chromosomes were selected from the Gramene database (http://www.gramene.org), and the polymorphic markers were used for frame mapping of a $BC_5F_5$ resistant line. Here, we developed 168 near-isogenic rice lines (NILs, $BC_6F_4$) to locate a QTL for resistance against bakanae disease. The lines were derived from a cross between Shingwang, a highly resistant variety (indica), and Ilpum, a highly susceptible variety (japonica). The 24 markers representing the Shingwang allele in a bakanae disease-resistant NIL, YR24982-9-1 (parental line of the $BC_6F_4$ NILs), were located on chromosome 1, 2, 7, 8, 10, 11, and 12. Single marker analysis using an SSR marker, RM9, showed that a major QTL was located on chromosome 1. The QTL explained 65 % of the total phenotype variation in $BC_6F_4$ NILs. The major QTL designated qBK1 was mapped in 91 kb region between InDel15 and InDel21. The identification of qBK1 and the closely linked SSR marker, InDel18, could be useful for improving rice bakanae disease resistance in marker-assisted breeding.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.446-454
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• 2008

An advanced extraction method by ultrasonic extraction with applied solid phase extraction (SPE) has been developed for the determination of simultaneous eight major ginsenosides, namely ginsenosides Rg1, Re, Rf, Rb1, Rg2, Rc, Rb2, and Rd in the root of Panax ginseng. Four extraction methods including n-BuOH reflux extraction (Method A), 70% EtOH reflux extraction (Method B), 50% MeOH reflux extraction with SPE (Method C), and 50% MeOH ultrasonication with SPE clean-up process (Method D) were investigated for the determination of eight major ginsenosides. Total contents of ginsenosides were highest by extraction of Method C as $2.408{\pm}0.011%$. However, Method D was evaluated as relatively simpler and more efficient method due to short extraction time, small solvent consumption and less expensive, compared to conservative reflux method. Ginsenosides were also satisfactorily separated with good resolution and the accuracy range was between 1.05 and 4.06% as relative standard deviation (RSD) by Method D. SPE condition and HPLC condition were further optimized for determination of eight major ginsenosides by the ultrasonic extraction method. Conclusively, ultrasonic extraction of 2 g sample of ginseng using ultrasonic bath and 1 loading for SPE was evaluated as proper condition for extraction of ginseng.