• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.419-423
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• 2003

Bacterial blight caused by Xantomonas oryzae pv. oryzae is one of the most serious diseases of rice especially in southern area of Korea. Three races, $\textrm{K}_1$, $\textrm{K}_2$ and $\textrm{K}_3$, are the most dominant species. lo improve rice breeding efficiency using marker assisted selection, some RFLP markers were surveyed for polymorphism between resistant and susceptible to $\textrm{K}_1$ and $\textrm{K}_3$. And, 127 doubled-haploid (DH) lines derived from Milyang121/HRl1650-1-4-2 and 131 DH lines derived from Milyang123/HR10624-AC5 were evaluated to bacterial blight ($\textrm{K}_1$ and $\textrm{K}_3$). Milyang121 and HR10624-AC5 have Xa-1, resistant to $\textrm{K}_1$ race, and Milyang123 has Xa-3, resistant to $\textrm{K}_1$ and $\textrm{K}_3$ race. Three markers, RZ590, RZ536 and RG303, showing polymorphism between parents and resistance gene, Xa-1 and Xa-3, were analysed in the two combinations of DH lines. The segregation pattern of resistant DH population of Milyang123/HR10624-AC5 to susceptible showed 3:1 and 1:1 in $\textrm{K}_1$ and $\textrm{K}_3$ race. In three RFLP markers, RZ590 was linked to Xa-1 on chromosome 4, and RZ536 and RG303 were linked to Xa-3 on chromosome 11. The map distance between Xa-1 and RZ590 was 3.1cM on chromosome 4, and Xa-3 and RZ536/RG303 were 7.6/16.0cM on chromosome 11, respectively. The results of RFLP mapping will be useful for the selection and pyramiding of bacterial blight resistant genes.

• Journal of Life Science
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• v.30 no.10
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• pp.844-850
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• 2020

Disaster-related extreme weather is rapidly increasing due to climate change. In Korea, typhoons accompanied by rainfall usually approach in August and September, causing great damage. The purpose of this study is to find a gene that regulates the heading date of rice in order to avoid loss of harvest from climate change and typhoons. Cheongcheong/Nagdong doubled haploid (CNDH) was used as the plant material to investigate the location of heading-related genes using QTL and sequence analysis by cloning the gene. In the distribution chart, the heading dates, culm lengths, panicle lengths, numbers of panicles, and 1,000-grain weights all have normal distributions. QTL analysis found 13 contigs on chromosome 8. One QTL, named qHd8, was detected on chromosome 8. The range at qHd8 was approximately 7.7 cM, with RM72 and RM404 markers near the peak. There were 13 contigs and 1 ORF. Protein sequence analysis showed that rice was similar to Os08g0341700, AtSFH13, and AtSFH7 proteins. Os08g0341700, which is involved in signal transduction, is similar to phosphatidylinositol transfer-like protein II, and complete information is not available, but it is believed to play a role in the phosphatidylinositol-specific signaling pathway related to Sec14P.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.573-578
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• 2012

A total of eleven Chinese cabbage accessions were used for microspore culture and were grown to take basal data. Based on the collected data, breeding materials were chosen to develop new improved Chinese cabbage cultivars. The range of microspore-derived embryoid taken from flower buds was 1.6 to 35.4 embryoids. The embryoids from IT26110 and IT26153 among the Chinese cabbages were more than 34 per flower bud. The viability rate after cold treatment was low from 0.2 to 11.7%. The range of fertility rate was 7.7 to 58.8% in general but the IT26118, IT26122, IT26128, IT26130, and IT26164 were more than 50%. The result of their seed production ability by selfing was 11.9 seeds per siliqua in IT26128 while the others were less than 10 seeds. In the microspore culture using parents of different hereditary, the number of embryoids, the number of plants, the rate of fertility and their pure seed production ability appeared to be very different in doubled haploid lines obtained from fertile plants of Chinese cabbage.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.56-61
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• 2011

Brown planthopper(BPH) is one of the most destructive insect pests of rice. The use of genetically resistant cultivars has proven to be a more economical, efficient and environment friendly means to combat this pest. This study was carried out to investigate the relationship between BPH resistant gene, Bph18 and yield components of rice using DH(doubled haploid) lines derived from 'Saenuri'/SR30071-3-7-23-6-1-1-1. SR30071-3-7-23-6-1-1-1 line has Bph18 gene derived from wild species, Oryza australiensis. BPH resistant gene, Bph18 shortened heading days, enlarged culm length and panicle length and reduced ratio of ripened grains of rice. The results indicate that backcrossing breeding is necessary to develop elite cultivars carrying Bph18 gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.1
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• pp.1-17
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• 2019

A quantitative trait loci (QTL) analysis of traits related to heading and yield was performed develop rice cultivars that are both early maturing and panicle weight type varieties. Our analysis included 120 strains of the Cheongcheong Nagdong doubled haploid (CNDH) variety. An observational growth experiment was conducted to identify genetic agronomic traits of CNDH. Heading date, ten plant weight, moisture, thousand grain weight, and yield had a normal distribution based on the frequency distribution table of the observational growth data. The QTL analysis found one heading-related and nine yield-related QTLs. The LOD of 2.85 was the largest in QTLs for heading date (QHD), 5.39 in QTLs for ten plant weight (QTPW), 3.92 in QTLs for moisture (QM), 4.80 in QTLs for thousand grain weight (QTGW), and 3.7 in QTLs for yield (QY). Genomic analysis detected 58 candidate genes on chromosome 2, 3, 7, 8, and 10. Among those, we found Rcd1 protein and OsERF3 gene in QM, MtN3 and zinc finger protein genes in QTGW, and OsNAC3 protein gene in QY. If further analysis reveals the presence of genes related to water content, thousand grain weight or yield in the CNDH stains, we can develop a selection of varieties that will be capable of coping with climate change and will contribute to global food problems.

• Journal of the Korean Society of Tobacco Science
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• v.14 no.1
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• pp.24-32
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• 1992

The present study was conducted to compare the relative efficiency of two different haploid breeding methods in tobacco varietal development. A single F t hybrid plant from cross of two flue-cured cultivars of Nicotiana tabacum L., Bright Yellow4(BY4) and NC 95, was used to develop the 30 dihaploid lines by anther culture(F1-ADH) and maternally-derived doubled haploid utilizing Nicotiana africana(F1-MDH), respectively. As compared with mid-parent, ADH lines showed increasing in number of leaves, delaying in days to flower and narrowing in leaf width. However, no significant differences in the other characters investigated were recognized. MDH lines also showed narrow leaf width, while no significant differences in the other characters were observed. The variations of the characters investigated were generally greater in ADH than MDH lines. MDH lines had higher plant height and shorter days to flower than ADH lines, while other characters did not show remarkable differences. The degree of heritability for each of the characters observed between ADH and MDH was almost the same. The characters showing high heritability value were plant height, leaf number, days to flower, and yield, while those showing relatively low value were leaf length, leaf width, and total alkaloid content. Predicted gains from selection for increased yield were calculated for both populations(F1-ADH, F1-MDH) and correlated responses associated with selection for yield were estimated. Plant height, leaf width, days to flower, percent reducing sugar and disease resistance would be expected to improve with selection for yield much faster in the MDH population than in the ADH.

• Korean Journal of Agricultural Science
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• v.38 no.4
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• pp.613-618
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• 2011

To develop clubroot resistant Chinese cabbage inbreds, IT 033820, a clubroot resistant turnip, was cross pollinated with a Chinese cabbage inbred of BP 079. From 2005, conventional breeding and microspore culture method performed using these F1 plants as parental materials. In 2007, conventional breeding method resulted in 21 F3 inbreds. After inoculation of clubroot race 4, one inbred showing 83% resistant was selected and registered as 'onkyo 20036ho' in 2008. From 2005, we scanned hybrid cultivars using micro spore culture and developed many doubled haploid (DH) lines in Chinese cabbage. Using Chinese cultivar of 'oong-baek 2ho' we developed 26 DH inbreds in 2007. After inoculation of clubroot race 4, one DH inbred showing 77% resistant and yellow inner leaf color was selected and registered as 'onkyo 20034'in 2008. We found conventional breeding method was effective using introduced germplasm showing low germination. However, when using hybrid cultivar as starting material, microspore culture method was powerful for developing various inbred in short time.

• Journal of Plant Biotechnology
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• v.35 no.4
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• pp.257-263
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• 2008

Improvement of the macro- and micro-elements density of rice (Oryza sativa L.) is gradually becoming a new breeding objective. In this study, the genomic regions associated with potassium, calcium, magnesium and iron content in rice grain were identified and characterized by using a doubled haploid (DH) population. Fifty-six simple sequence repeat (SSR) and one hundred and twelve sequence tagged site (STS) markers were selected to construct the genetic linkage map of the DH population with a full length of 1808.3cM scanning 12 rice chromosomes. Quantitative trait loci (QTLs) were detected, and QTL effects and QTL interactions were calculated for five traits related to macro- and micro-elements in the DH population from a cross between 'Samgang' (Tongil) and 'Nagdong' (Japonica). Twelve QTLs were located on five chromosomes, consisting of two QTLs for potassium, three QTLs for calcium, two QTLs for magnesium, one QTL for iron content and four QTLs for the ratio of magnesium to potassium (Mg/K). Among them, qca1.1 was detected on chromosome 1 with an LOD value of 8.58 for calcium content. It explained 27% of phenotype variations with increasing effects from 'Samgang' allele. Furthermore, fifteen epistatic combinations with significant interactions were observed on ten chromosomes for five traits, which totally accounted for 4.19% to 12.72% of phenotype variations. The screening of relatively accurate QTLs will contribute to increase the efficiency of marker-assisted selection (MAS), and to accelerate the establishment of near-isogenic lines (NILs) and QTL pyramiding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.105-110
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• 2010

This study was conducted to analyze the relationships between resistance of brown planthopper and traits related to the lodging in rice. For the linkage analysis of traits tested in this study, a genetic linkage map was created with 162 DNA markers spanning 12 rice chromosomes based on 120 doubled haploid (DH) lines, which were derived from a cross between Samgang', a Tongil type cultivar with BPH resistance, and ‘Nagdong’, a japonica cultivar. QTLs were identified to analyze the agronomic traits including lodging by composite interval mapping. Thirteen QTLs were detected for five traits comprised of plant length (PL), 3rd internode length (3rdIL), moments (Mo), lodging index (LI), and breaking weight (BW). The relationships between the BPH resistance and agronomic traits including lodging revealed that two QTLs (qBPR7, qBPR8) were linked to traits related to lodging. Two QTLs, qBPR7 and qBPR8 on chromosome 7 (RM531-7042) and 8 (RM1148- RM544) showed associations with moments and 3rd internode length, respectively.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.112-124
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• 2019

Barley worldwide is affected seriously by Fusarium seedling blight (FSB) and Fusarium head blight (FHB) diseases caused by the Fusarium species. The objective of this study was to facilitate the resistance of hulled and hull-less barley at different growth stages to F. culmorum according to direct parameters: disease rating (DR), fresh weight of leaves and roots, kernel weight per spike, kernel number per spike, plump kernels, and indirect parameters - chlorophyll a fluorescence (CF). Plate assay, greenhouse and field tests were performed on 30 spring barley doubled haploid (DH) lines and their parents infected with Fusarium culmorum. Direct parameters proved that hulled genotypes show less symptoms. Most studied chlorophyll a fluorescence (CF) parameters (apart from DIo/CS - amount of energy dissipated from PSII for laboratory test, TRo/CS - amount of excitation energy trapped in PSII reaction centers, ETo/CS - amount of energy used for electron transport and RC/CS - number of active reaction centres in the state of fully reduced PSII reaction center in field experiment) were significantly affected by F. culmorum infection. In all experiments, hulled genotypes had higher values of CF parameters compared to hull-less ones. Significant correlations were detected between direct and indirect parameters and also between various environments. It was revealed that ABS/CS, TRo/CS, and RC/CS have significant positive correlation in greenhouse test and field experiment. Significant correlations suggest the possibility of applying the CF parameters in selection of barley DH lines resistant to F. culmorum infection.