• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.939-948
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• 2003

The objective of this study was to identify the quantitative traits loci(QTL) for economically important traits such as growth, carcass and meat quality on pig chromosome 6. A three generation resource population was constructed from cross between Korean native boars and Landrace sows. A total of 240 F$_2$ animals were produced using intercross between 10 boars and 31 sows of F$_1$ animals. Phenotypic data including body weight at 3 weeks, backfat thickness, muscle pH, shear force and crude protein level were collected from F$_2$ animals. Animals including grandparents(F$_0$), parents(F$_1$) and offspring(F$_2$) were genotyped for 29 microsatellite markers and PCR-RFLP marker on chromosome 6. The linkage analysis was performed using CRI-MAP software version 2.4(Green et al., 1990) with FIXED option to obtain the map distances. The total length of SSC6 linkage map estimated in this study was 169.3cM. The average distance between adjacent markers was 6.05cM. For mapping of QTL, we used F$_2$ QTL Analysis Servlet of QTL express, a web-based QTL mapping tool(http://qtl.cap.ed.ac.uk). Five QTLs were detected at 5% chromosome-wide level for body weight of 3 weeks of age, shear force, meat pH at 24 hours after slaughtering, backfat thickness and crude protein level on SSC6.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.303-313
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• 2020

Rice grain shape is one of the key components of grain yield and market value. An understanding of the genetic basis of the variation in grain shape could be used to improve grain shape. In this study, we developed a total of 265 F₂ individuals derived from a cross between japonica cultivars (Josaeng-jado and Langi) and used this population for quantitative trait locus (QLT) analysis. Correlation analysis was performed to identify relationships between grain traits (GL: grain length, GW: grain width, L/W: ratio of length to width, TGW: 1,000 grain weight). The grain shape was positively correlated with GL and TGW, and negatively correlated with GW. In QTL analysis associated with grain shape, one QTL for GL, qGL5, detected on chromosome 5, explained 20.3% of the phenotypic variation (PV), while two QTLs, qGW5 (PV=36.1) and qGW7 (PV=26.1), for GW were identified on chromosomes 5 and 7, respectively. Evaluation of the effects of each of the QTLs on the grain shape in the population showed a significant difference in the grain size in positive lines compared with the lines without the QTLs. According to the QTL combination of the allelic-types, the grain shape of the tested lines varied from semi-round type to long spindle-shaped type. The results of this study extend our knowledge about the genetic pool governing the diversity of grain shape in japonica cultivars and could be used to improve the grain shape of this species through marker-assisted selective breeding in Korea.

• Plant Biotechnology Reports
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• v.5 no.2
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• pp.135-146
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• 2011

The objective of the present research was to map QTLs associated with agronomic traits such as days from sowing to flowering, plant height, yield and leaf-related traits in a population of recombinant inbred lines (RILs) of sunflower (Helianthus annuus). Two field experiments were conducted with well-irrigated and partially irrigated conditions in randomized complete block design with three replications. A map with 304 AFLP and 191 SSR markers with a mean density of 1 marker per 3.7 cM was used to identify QTLs related to the studied traits. The difference among RILs was significant for all studied traits in both conditions. Three to seven QTLs were found for each studied trait in both conditions. The percentage of phenotypic variance ($R^2$) explained by QTLs ranged from 4 to 49%. Three to six QTLs were found for each yield-related trait in both conditions. The most important QTL for grain yield per plant on linkage group 13 (GYP-P-13-1) under partial-irrigated condition controls 49% of phenotypic variance ($R^2$). The most important QTL for 1,000-grain weight (TGW-P-11-1) was identified on linkage group 11. Favorable alleles for this QTL come from RHA266. The major QTL for days from sowing to flowering (DSF-P-14-1) were observed on linkage group 14 and explained 38% of the phenotypic variance. The positive alleles for this QTL come from RHA266. The major QTL for HD (HD-P-13-1) was also identified on linkage group 13 and explained 37% of the phenotypic variance. Both parents (PAC2 and RHA266) contributed to QTLs controlling leaf-related traits in both conditions. Common QTL for leaf area at flowering (LAF-P-12-1, LAF-W-12-1) was detected in linkage group 12. The results emphasise the importance of the role of linkage groups 2, 10 and 13 for studied traits. Genomic regions on the linkage groups 9 and 12 are specific for QTLs of leaf-related traits in sunflower.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1184-1191
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• 2011

We attempted to generate a linkage map using Illumina Porcine 60K SNP Beadchip genotypes of the $F_2$ offspring from Korean native pig (KNP) crossed with Yorkshire (YS) pig, and to identify quantitative trait loci (QTL) using the line-cross model. Among the genotype information of the 62,136 SNPs obtained from the high-density SNP analysis, 45,308 SNPs were used to select informative markers with allelic frequencies >0.7 between the KNP (n = 16) and YS (n = 8) F0 animals. Of the selected SNP markers, a final set of 500 SNPs with polymorphic information contents (PIC) values of >0.300 in the $F_2$ groups (n = 252) was used for detection of thirty meat quality-related QTL on chromosomes at the 5% significance level and 10 QTL at the 1% significance level. The QTL for crude protein were detected on SSC2, SSC3, SSC6, SSC9 and SSC12; for intramuscular fat and marbling on SSC2, SSC8, SSC12, SSC14 and SSC18; meat color measurements on SSC1, SSC3, SSC4, SSC5, SSC6, SSC10, SSC11, SSC12, SSC16 and SSC18; water content related measurements in pork were detected on SSC4, SSC6, SSC7, SSC10, SSC12 and SSC14. Additional QTL of pork quality traits such as texture, tenderness and pH were detected on SSC6, SSC12, SSC13 and SSC16. The most important chromosomal region of superior pork quality in KNP compared to YS was identified on SSC12. Our results demonstrated that a QTL linkage map of the $F_2$ design in the pig breed can be generated with a selected data set of high density SNP genotypes. The QTL regions detected in this study will provide useful information for identifying genetic factors related to better pork quality in KNP.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.712-721
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• 1997

The objectives of this study were; (1) to identify and localize QTLs for resistance to soybean cyst nematode(SCN) race 5 on RAPD map, (2) to idntify the magnitude and mode of inheritance for each QTL, and (3) to identify the best combinations of QTLs for resistance to SCN race 5. Based on the univariate regression analysis, we detected 26 markers(22 RAPD and 4 RFLP) which showed significant association(P<0.05) with resistance to SCN race 5. From MAPMAKER /QTL analysis, we identified two regions (LGC-20 and Group 2) for resistance to SCN race 5. The QTL that was localized at 8.0 cM from pK418C on LGC-20 showed a recessive mode of inheritance and the QTL that was localized between W03 and E02$^3$ on Group 2 showed a dominant mode of inheritance. Two pairs of flanking markers (E02$^3$ and W03, pK418C and pK418E$_1$) and one unlinked RAPD marker, G10$^1$ were used for multiple regression analysis. Marker combination which was composed of 4 markers, E02$^3$, G10$^1$, W03, and pK418E$_1$, explained the highest amount of phenotypic variation by SCN (35.2％). Further research for the identification of QTLs for resistance to SCN race 5 to explain larger portion of phenotypic variation is needed.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1402-1405
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• 2003

The QTL(quantitative traits loci) linkage mapping of Hanwoo (Korean Cattle) chromosome 6 for daily gain and marbling score was performed using 378 individuals from 18 paternal half-sib families in Hanwoo. Hanwoo chromosome 6 were mapped to total length of 394.2 cM between 28 microsatellite loci using 36 microsatellite primers of BTA 6 linkage group. The QTL analysis for daily gain in Hanwoo showed 8 microsatellite loci (BM3026-5.66, EL03-5.58, BM4311-5.29, ILSTS035-4.50, BMS1242-4.37, BM1329-3.67, BM415-3.11, BMS2460-3.03) in larger than LOD score 3.0. Based on the QTL analysis for marbling score, LOD scores of 12 microsatellite loci (BM415-8.88, BM3026-7.15, ILSTS093-5.45, ILSTS035-4.91, EL03-4.69, BMS690-4.52, BM1329-4.43, BMS511-3.74, BMS1242-3.66, BMS518-3.65, BM4311-3.41, BMC4203-3.36) were found larger than 3.0.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.102-102
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• 2017

In this study, QTL analysis of allelopathy was conducted. A total of 171 of F8 RILs developed from the cross between Nongan(low allelopathic cultivar) and Sathi(high allelopathic cultivar) were used . the performance of allelopathy were evaluated using 'ECAM(Equal Compartment Agar Method)', where the root length of lettuce cultivated with the RILs were measured. The distribution of the performance was followed as normal distribution. In order to identify the location of QTLs related to allelopathy, QTL-seq with BSA(Bulked-segregant analysis) was performed with 20 highest and 10 lowest RILs. As a result, Two Sliding window coordinate region of candidate QTLs were detected on Chr4 (5,050,001 - 14,800,000, 18,650,001 - 22,500,000), Chr8 (2,550,001 - 8,250,000, 21,150,001 - 26,800,000) and One region on Chr7 (1 - 3,300,000), Chr9 (1 - 13,300,000) respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1406-1410
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• 2014

Age at first calving is an important trait for achieving earlier reproductive performance. To detect quantitative trait loci (QTL) for reproductive traits, a genome wide association study was conducted on the 96 Hanwoo cows that were born between 2008 and 2010 from 13 sires in a local farm (Juk-Am Hanwoo farm, Suncheon, Korea) and genotyped with the Illumina 50K bovine single nucleotide polymorphism (SNP) chips. Phenotypes were regressed on additive and dominance effects for each SNP using a simple linear regression model after the effects of birth-year-month and polygenes were considered. A forward regression procedure was applied to determine the best set of SNPs for age at first calving. A total of 15 QTL were detected at the comparison-wise 0.001 level. Two QTL with strong statistical evidence were found at 128.9 Mb and 111.1 Mb on bovine chromosomes (BTA) 2 and 7, respectively, each of which accounted for 22% of the phenotypic variance. Also, five significant SNPs were detected on BTAs 10, 16, 20, 26, and 29. Multiple QTL were found on BTAs 1, 2, 7, and 14. The significant QTLs may be applied via marker assisted selection to increase rate of genetic gain for the trait, after validation tests in other Hanwoo cow populations.

• Journal of Life Science
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• v.7 no.4
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• pp.358-360
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• 1997

Soybean [Glycine max (L.) Merr.] seed size is a important yield component and is a primary consideration in the development of cultivars for specialty markets. Our objective was to examine the consistency of QTLs for seed size across generations. A 68-plant F$_{2} segregation population derived from a mating between Marcury (small seed) and PI 467.468 (large seed) was evaluated with RAPD markers. In the F$_{2} plant generation (i.e. F$_{3} seed), three markers, OPL09a, OPM)7a, and OPAC12 were significantly (P<0.01) associated with seed size QTLs. In the F$_{2} ; F$_{3} generation (i.e., F$_{4} seed), four markers, OPA092, OPG19, OPL09b, and OPP11 were significantly (P<0.01) associated with seed size QTLs. Just two markers, OPL09a, and OPL09b were significantly (P<0.05) associated with seed size QTLs in both generations. The consistency of QTLs across generations indicates that marker-assisted selection for seed size is possible in a soybean breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.85-92
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• 2008

An RIL population from a Shinpaldalkong2/GC83006 cross was employed to identify quantitative trait loci (QTL) associated with agronomic traits in soybean. The genetic map consisted of 127 loci which covered about 3,000cM and were assigned into 20 linkage groups. Phenotypic data were collected for the following traits; plant height, leaf area, flowering time, pubescence color, seed coat color and hilum color in 2005. Seed weight was evaluated using seeds collected in 2003 to 2005 at Suwon and in 2005 at Pyeongchang and Miryang sites. Three QTLs were associated with 100-seed weight in the combined analysis across three years. Among the three QTLs related to seed weight, all GC83006 alleles on LG O ($R^2\;=\;12.5$), LG A1 ($R^2\;=\;10.1$) and LG C2 ($R^2\;=\;11.5$) increased the seed weight. A QTL conditioning plant height was linked to markers including Satt134 (LG C2, $R^2\;=\;25.4$), and the GC83006 allele increased plant height at this QTL locus. For two QTLs related to leaf area, 1aM on LG M ($R^2\;=\;10.0$) and laL on LG L ($R^2\;=\;8.6$), the Shinpaldalkong2 alleles had positive effect to increase the leaf area. Satt134 on LG C2 ($R^2\;=\;41.0$) was associated with QTL for days to flowering. Satt134 (LG C2) showed a linkage to a gene for pubescence color. Satt363 (LG C2) and Satt354 (LG I) were linked to the hilum color gene, and Sat077 (LG D1a) was linked to the seed coat color. The QTL conditioning plant height was in the similar genomic location as the QTLs for days to flowering in this population, indicating pleiotropic effect of one gene or the tight linkage of several genes. These linked markers would be useful in marker assisted selection for these traits in a soybean breeding program.