• Plant Biotechnology Reports
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• v.4 no.1
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• pp.61-73
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• 2010

Quantitative trait loci (QTL) associated with six physical traits of cooked rice and seven chemical properties of rice grain were identified using a recombinant inbred (RI) population of rice evaluated over 3 years at the National Honam Agricultural Research Institute in Korea. The RI population consisted of 164 lines derived from a cross between Milyang23 and Gihobyeo, and the genetic map consisted of 414 molecular markers. A total of 49 QTL were identified for the 13 physico-chemical properties using composite interval mapping. Of these, 13 QTL were identified for 2 or more years, while 36 were detected in only 1 year. Five QTL were identified over all 3 years and will be useful for marker-assisted improvement of rice grain quality in Korea. The two QTL with the highest LOD scores, adhesiveness1.2 and potassium content7.1, provide a valuable starting point for positional cloning of genes underlying these QTL.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.169-174
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• 2012

Quantitative trait loci (QTLs), which were related to the ability of callus induction and plant regeneration in seed culture of rice, were analyzed using a mapping population from a cross between the rice cultivars 'Samgang' (tongil type) and 'Nagdong' (japonica). A tongil type rice cultivar, 'Samgang' showed lower frequency (20%) of plant regeneration than that (35%) of japonica rice, 'Nagdong'. Transgressive segregations were observed for the ability of callus induction and plant regeneration from the seed-derived calli of 58 doubled haploid (DH) lines. The ability of plant regeneration of 58 doubled haploid lines showed a continuous distribution with comparatively wide range (10.0 to 66.7%) of variation. Composite interval mapping analysis was used to identify the QTLs controlling callus induction and plant regeneration ability. Four significant QTLs, qCWS6, qCWS8, qCWS9 and qCWS11, associated with callus weight per seed were detected on chromosomes 6, 8, 9, and 11 with LOD values of 3.30, 2.60, 2.70 and 2.43, explaining 36% of the total phenotypic variation. Three significant QTLs, qPR1, qPR6, and qPR11, for the ability of plant regeneration were located on chromosome 1, 6, and 11 at LOD score of 2.25, 2.15 and 2.55, accounting for 24 % of the total phenotypic variation. The present study should be useful for improving the efficiency of plant regeneration in tissue culture of indica rice by means of marker-assisted selection.

• Molecules and Cells
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• v.21 no.2
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• pp.192-196
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• 2006

Salt tolerance was evaluated at the young seedling stage of rice (Oryza sativa L.) using recombinant inbred lines (MG RILs) from a cross between Milyang 23 (japonica/indica) and Gihobyeo (japonica). 22 of 164 MG RILs were classified as tolerant with visual scores of 3.5-5.0 in 0.7% NaCl. Interval mapping of QTLs related to salt tolerance was conducted on the basis of the visual scores at the young seedling stage. Two QTLs, qST1 and qST3, conferring salt tolerance, were detected on chromosome 1 and 3, respectively, and the total phenotypic variance explained by the two QTLs was 36.9% in the MG RIL population. qST1 was the major QTL explaining 27.8% of the total phenotypic variation. qST1 was flanked by Est12~RZ569A, and qST3 was flanked by RG179~RZ596. The detection of new QTLs associated with salt tolerance will provide important information for the functional analysis of rice salt tolerance.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1061-1065
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• 2017

Objective: This study was conducted to locate quantitative trait loci (QTL) influencing fatty acid (FA) composition in a large $F_2$ intercross between Landrace and Korean native pigs. Methods: Eighteen FA composition traits were measured in more than 960 $F_2$ progeny. All experimental animals were genotyped with 165 microsatellite markers located throughout the pig autosomes. Results: We detected 112 QTLs for the FA composition; Forty seven QTLs reached the genome-wide significant threshold. In particular, we identified a cluster of highly significant QTLs for FA composition on SSC12. QTL for polyunsaturated fatty acid on pig chromosome 12 (F-value = 97.2 under additive and dominance model, nominal p-value $3.6{\times}10^{-39}$) accounted for 16.9% of phenotypic variance. In addition, four more QTLs for C18:1, C18:2, C20:4, and monounsaturated fatty acids on the similar position explained more than 10% of phenotypic variance. Conclusion: Our findings of a major QTL for FA composition presented here could provide helpful information to locate causative variants to improve meat quality traits in pigs.

• Journal of Life Science
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• v.19 no.9
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• pp.1239-1244
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• 2009

This study was conducted to clarify the genetic relationship between Calanthe discolor, C. sieboldii and variants, and the cause of flower color variations by using a molecular linkage map and a quantitative trait loci (QTL) analysis for flower and lip color in Calanthe species native to Korea. Twenty plants were included in three C. discolor and three C. sieboldii, and fourteen variants were obtained from their habitat, Jeju-do in Korea. The flowers of C. discolor were brownish red, the values of Commission Internationale de I'Eclairage (CIE) Lab were between 40 and 50. The flowers of C. sieboldii were yellowish, the values of CIE Lab were between 110 and 130. The variants had various mixed colors that were thought to have originated from natural hybridization between C. discolor and C. sieboldii, and the values of CIE Lab were between 50 and 70. The colors of the lips were usually divided into white and yellow. C. discolor had a white lip, C. sieboldii had a yellow one, and the variants had a white to yellow one. The CIE Lab value of each color was 90 in white and 110 to 120 in yellow lips. A molecular linkage mapping was constructed based on the segregation of 154 RAPD markers using a MAPL program. Sixteen linkage groups containing 66 markers were established. It covered a total map distance of 220.4 cM. The distance between adjacent markers ranged from 0 to 6.6 cM, with an average distance of 3.3 cM. These markers are thought to be closely associated with flower and lip color expression. Among the 16 molecular linkage groups, 3 QTLs had flower color trait loci and 1 QTL had lip color trait loci.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.11
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• pp.1537-1544
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• 2015

Meat and carcass quality attributes are of crucial importance influencing consumer preference and profitability in the pork industry. A set of 400 Berkshire pigs were collected from Dasan breeding farm, Namwon, Chonbuk province, Korea that were born between 2012 and 2013. To perform genome wide association studies (GWAS), eleven meat and carcass quality traits were considered, including carcass weight, backfat thickness, pH value after 24 hours (pH24), Commission Internationale de l'Eclairage lightness in meat color (CIE L), redness in meat color (CIE a), yellowness in meat color (CIE b), filtering, drip loss, heat loss, shear force and marbling score. All of the 400 animals were genotyped with the Porcine 62K SNP BeadChips (Illumina Inc., USA). A SAS general linear model procedure (SAS version 9.2) was used to pre-adjust the animal phenotypes before GWAS with sire and sex effects as fixed effects and slaughter age as a covariate. After fitting the fixed and covariate factors in the model, the residuals of the phenotype regressed on additive effects of each single nucleotide polymorphism (SNP) under a linear regression model (PLINK version 1.07). The significant SNPs after permutation testing at a chromosome-wise level were subjected to stepwise regression analysis to determine the best set of SNP markers. A total of 55 significant (p<0.05) SNPs or quantitative trait loci (QTL) were detected on various chromosomes. The QTLs explained from 5.06% to 8.28% of the total phenotypic variation of the traits. Some QTLs with pleiotropic effect were also identified. A pair of significant QTL for pH24 was also found to affect both CIE L and drip loss percentage. The significant QTL after characterization of the functional candidate genes on the QTL or around the QTL region may be effectively and efficiently used in marker assisted selection to achieve enhanced genetic improvement of the trait considered.

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.315-325
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• 2015

Recently, livestock breeding is more focused on the meat quality rather than meat quantity, mainly due to the improvement of consumers' income. Among the meat quality traits, meat color is one of very important traits because meat color is the first selection criterion from the consumers in the market. Most of the economically important traits have continuous variations and these are called quantitative traits. the genomic locations affecting these traits are called quantitative trait locus (QTL), which is mostly controlled by many genes having small effects. In this study, the recent QTL and candidate gene studies were reviewed in order to meet the consumers' demand for the future market. In the chicken QTL database, three traits are related with meat colors, namely breast color (Bco), meat color (Mco), drip loss (DL) and pH. The identified number of QTLs is 33 from 13 chromosomal regions. In these QTL regions, 14 candidate genes were identified; Eight for meat color (APP, BCMO1, COL1A2, FTO, KPNA2, PSMD12, G0S2, FTSJ3), two for drip loss (AGRP, FTO) and four for pH (GALNT1, PCDH19, DIAPH1, SPP2). These QTLs and candidate genes need to be confirmed and fine mapping is ultimately needed for identification of causative variations. The recently developed chicken resource population using Korean native chicken can be used for the improvement of meat quality traits, which increase the value that needed in the chicken industry.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1350-1353
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• 2004

To further investigate the regions on porcine chromosome 7 that are responsible for economically important traits, phenotypic data from a total of 287 F2 individuals were collected and analyzed from 1998 to 2000. All animals were genotyped for eight microsatellite loci spanning the length of chromosome 7. QTL analysis was performed using interval mapping under the line-cross model. A permutation test was used to establish significance levels associated with QTL effects. Observed QTL effects were (chromosomewide significance, position of maximum significance in centimorgans): Birth weight (<0.01, 3); Carcass length (<0.05, 80); Longissimus muscle area (<0.01, 69); Skin percentage (<0.01, 69); Bone percentage (<0.01, 74); Fat depths at shoulder (<0.05, 54);Mean fat depth (<0.05, 81); Moisture in m. Longissimus Dorsi (<0.05, 88). Additional evidence was also found which suggested QTL for dressing percentage and fat depths at buttock. This study offers confirmation of several QTL affecting growth and carcass traits on SSC7 and provides an important step in the search for the actual major genes involved in the traits of economic interest.

• Journal of Life Science
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• v.18 no.12
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• pp.1665-1670
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• 2008

Soybean oil is an important source of vegetable oil for human food and nonfood applications and accounts for approximately 22% of the world's total edible oil production. Improvement of the quality and quantity of soybean seed oil constituents is one of the most important objectives in soybean breeding. The objective of this study was to identify quantitative trait loci (QTLs) that control oleic, linoleic, and linolenic acid contents in soybean. The 117 $F_{2:10}$ recombinant inbred lines (RIL) developed from a cross of 'Keunolkong' and 'Shinpaldalkong' were used. Narrow-sense heritability estimates based on a plot mean on seed weight, protein and oil content were 0.85, 0.82 and 0.81, respectively. Eight independent QTLs for oleic acid content were identified from linkage group (LG) A2, C1, D2, F, G, L, and O. Seven QTLs for linoleic acid content were located on LG D1b, E, H, I and L. Oil content was related with five QTLs located on LG C1, H, J, K, and L. Oleic, linoleic, and linolenic acid have two common QTLs on LG C1 and L. Thus, we identified major loci improving soybean oil quality.

• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.477-482
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• 2012

Low-temperature germination is one of the major determinants for stable stand establishment in the rice direct seeding method in temperate regions and at high altitude areas. Quantitative trait loci (QTL) controlling low-temperature germinability in rice were identified using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon and the Korean japonica cultivar, 'Hwaseongbyeo'. The germination rate at $15^{\circ}C$ was measured to represent low-temperature germination and used for QTL analysis. The germination rate at $15^{\circ}C$ for 7 days of Oryza rufipogon and Hwaseongbyeo was 93.3 and 28.7%, respectively, and that of progenies ranged from 0 to 48%. A linkage map was constructed using 135 simple sequence repeat (SSR) markers. Five putative QTLs associated with low-temperature germination were detected on chromosomes 1, 3, 4, 10 and 11. The QTL, qltg10 on chromosome 10 accounted for 19.2% of the total phenotypic variation for low-temperature germinability. Four additional QTL, accounted for 10.4 - 15.1% of the total phenotypic variation. The O. rufipogon alleles in all detected QTLs loci increased the low-temperature germination rate. No QTL associated with low temperature germinability has been detected near the qltg10 QTL in this study suggesting that qltg10 is a new QTL. The locus, qltg10 is of particular interest because of its independence from undesirable height and maturity effects. The DNA markers linked to the QTL for low temperature germinability would be useful in selecting lines with enhanced low temperature germinability in rice breeding program.