• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.669-676
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• 2007

This study was conducted to detect quantitative trait loci (QTL) affecting growth and body composition in an $F_2$ reference population of Korean native pig and Landrace crossbreds. The three-generation mapping population was generated with 411 progeny from 38 $F_2$ full-sib families, and 133 genetic markers were used to produce a sex-average map of the 18 autosomes. The data set was analyzed using least squares Mendelian and parent-of-origin interval-mapping models. Lack-of-fit tests between the models were used to characterize QTL for mode of expressions. A total of 8 (39) QTL were detected at the 5% genome (chromosome)-wise level for the 17 analyzed traits. Of the 47 QTL detected, 21 QTL were classified as Mendelian expressed, 13 QTL as paternally expressed, 6 QTL as maternally expressed, and 7 QTL as partially expressed. Of the detected QTL at 5% genome-wise level, two QTL had Mendelian mode of inheritance on SSC6 and SSC9 for backfat thickness and bone weight, respectively, two QTL were maternally expressed for leather weight and front leg weight on SSC6 and SSC12, respectively, one QTL was paternally expressed for birth weight on SSC4, and three QTL were partially expressed for hot carcass weight and rear leg weight on SSC6, and bone weight on SSC13. Many of the Mendelian QTL had a dominant (complete or overdominant) mode of gene action, and only a few of the QTL were primarily additive, which reflects that heterosis for growth is appreciable in a cross between Korean native pig and Landrace. Our results indicate that alternate breed alleles of growth and body composition QTL are segregating between the two breeds, which could be utilized for genetic improvement of growth via marker-assisted selection.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.59-62
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• 2002

The role of a TolC homologue in the virulence of Vibrio vulnificus, a marine bacterium causing serious wound infection and fulminant septicemia in persons with underlying conditions, has been studied. TolC, an outer membrane protein, has been implicated in a variety of bacterial functions including export of diverse molecules ranging from large proteins to antibiotics. A homologue of the tolC gene of V. cholerae, which has been shown to be required for bile resistance, cytotoxicity and colonization of this organism, was identified in the partially determined genome sequence of V. vulnificus. To determine the role of TolC in the virulence of V. vulnificus, a TolC-deficient (TD) mutant was isolated by in vivo allelic exchange. Compared with the parent strain, the TD mutant was more sensitive to bile, and much less virulent in mice challenged subcutaneously. This mutant was noncytotoxic to the HEp-2 cells, but its metalloprotease and cytolysin activities in the culture supernatant were comparable to the parent strain. In addition, the resistance of the TD mutant to human serum bactericidal activity as well as its growth in either human or murine blood was not affected. Collectively, our data suggest that TolC may be involved in colonization and/or spread of V. vulnificus to the blood stream, probably by secreting a cytotoxin other than the cytolysin.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.462-465
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• 1987

Three F$_1$ hybrids, Seokwang/Milyang 54, HR1619-6-2-1-2-2/Milyang 54 and 55061/IR19735-5-2-3-2-1, and their parents were inoculated with each of four individual blast races, IC-l3, IH-l, IA-61 and IB-47, and the mixtures of two races, IC-13 and IH-l, IC-13 and IA-61, and IC-13 and IB-47, respectively. The varietal reactions to the tested races showed that two parental varieties of each cross, Seokwang and Milyang 54, HR1619-6-2-1-2-2 and Milyang 54, and 55061 and IR19735-5-2-3-2-1 have different resistance gene(s) respectively. The F 1 hybrids between two cultivars having different resistant genes were resistant to the mixture of two races of which one race was virulent to one parent and avirulent to the other parent respectively, while the parents of these F$_1$s were susceptible. This may suggest that the F$_1$ hybrids have wider spectrum resistance to leaf blast than their parents.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.360-367
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• 2011

Beta-carotene producing transformants were produced in the background of 'Nagdongbyeo', a Japonica rice cultivar. Introgression of the carotenoid locus in the transformant, PAC4-2 into the elite cultivar 'Ilpumbyeo' was started. To initiate a backcrossing program, we surveyed 220 SSR markers and found that 38% of them were polymorphic between 'Ilpumbyeo' as a recurrent parent and the PAC4-2 as a recipient parent. The selection strategy comprising foreground and background selection was employed. First, foreground selection was practiced in $BC_1$, $BC_2$, and $BC_3$ generations using the transgene specific PCR-based marker in addition to visual scoring of the seed color. Marker-based background selection combined with phenotypic selection was employed from $BC_3F_2$ to $BC_3F_4$ generations. Blast search indicated that the transgene PAC4-2 was located between SSR markers, RM6 and RM482. 240 $BC_3F_3$ and 63 $BC_3F_4$ lines were evaluated for four agronomic traits including days to heading. Most of the lines were similar to Ilpumbyeo in agronomic traits evaluated. The percentage of PAC4-2 genome ranged from 4% to 21% with a mean of 12.5%, which was higher than the expected for an unselected $BC_3$ backcross population. This could be explained by the fact that two genes for beta-carotene and the stripe virus resistance were targeted in this study. We selected 10 representative $BC_3F_5$ lines from 63 $BC_3F_4$ lines based on agronomic traits and carotenoids content. The selection strategy would be appropriate for the introgression of beta-carotene gene in a breeding program.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.294-303
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• 2023

Lipoxygenase gives soybeans their grassy flavor, which can disrupt food processing efficiency. This study aimed to identify soybean genotypes with lipoxygenase deficiency among 1,001 soybean accessions and to develop kompetitive allele specific PCR (KASP) markers that can detect lipoxygenase mutations. Three lipoxygenase isozymes (Lox1, Lox2, and Lox3) were analyzed using a colorimetric assay based on a substrate-enzyme reaction. Among the 1,001 accessions examined, two (IT160160 and IT276392) exhibited a deficiency solely in Lox1, and one (IT269984) lacked both Lox1 and Lox2. IT160160 had a 74-bp deletion in exon 8 of Lox1 (Glyma13g347600), whereas IT276392 displayed a missense mutation involving the change of C to A at position 2,880 of Lox1. Moreover, we successfully developed four KASP markers that specifically target Lox1, Lox2, and Lox3 mutations. To validate the Lox1 KASP markers, we used two F_2:3 populations generated through a cross between Daepung 2 (lipoxygenase wild type, maternal parent), IT160160, and IT276392 (null Lox1, paternal parent). The results revealed that the Daepung 2 × IT160160 group followed the expected 3:1 ratio according to Mendel's law, whereas the Daepung 2 × IT276392 group did not. Furthermore, a comparison between the colorimetric and KASP marker analyses results revealed a high agreement rate of 96%. KASP markers offer a distinct advantage by allowing the distinction of heterozygous types independent of other variables. As a result, we present an opportunity to expedite the lipoxygenase-deficient cultivar development.

• Korean Journal of Breeding Science
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• v.41 no.1
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• pp.1-8
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• 2009

This study was carried out to breed and develop high quality and functional nutrient tomato with multi disease resistance as well as a stable growing adaptation for fresh market usage under protected plastic houses cultivation. The materials were used 5 inbred lines and their 6 hybrids of large tomato group, which have been bred and developed from 1999 to 2007 in Division of Plant Resource Department of Chungnam National University. Fruit weight showed hybrid vigor effect that $F_1$ hybrids weighed more than their parent lines, fruit shape formed three type of oblate, deep oblate and globe shape, in firmness and pericarp thickness have got a high significant correlation, inbred DN611 line was measured the most firm fruit with 6.04 mm pericarp thickness. In fruit color at maturity, pink color crossed to red color appeared all red fruit color in the $F_1$ hybrids, it means red skin color is a dominant gene compared to pink skin color is a recessive gene in tomato, while between fruit skin color and shoulder part color showed no any co-relationship. The sugar content and titratable acid of $F_1$ hybrids inherited an intermediate data of their parent lines, the flavor of KP543 inbred line and the hybrid (JB535 x KP543) revealed the better taste with high brix and proper titratable acid content$^{*}$. In beta carotene content DN611 line showed 2~3 times higher than other materials so that its 3 hybrids contained an increased level of beta carotene, lycopene content was not so much difference among inbred lines and $F_1$ hybrids, of them MD508 contained higher of 8.72 mg and hybrid (JB535 x JA517) had 8.05 mg lycopene content per 100 g fruit, overall pink skin color and red skin color measured a higher lycopene content than yellow and orange skin color at ripe stage. In disease resistance test by PCR marker for Fusarium race2 (I2), Nematode (Mi1), ToMV ($Tm2^2$), Cladosporium (Cf9), (JB535 x JA517) hybrid have got multi-resistance with homozygote band in Nematode, ToMV, Cladosporium and heterozygote band in Fusarium race2. Through this breeding program we could select high quality and functional nutrient with multi resistant $F_1$ hybrids and inbred lines in tomato which are two best hybrids (JB535 x MD508), (JB535 x JA517), additionally developed high beta carotene inbred line DN611 and increased the level of lycopene inbred line MD508. These results will be very useful to make a high quality tomato variety continuously.

• Korean Journal of Ichthyology
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• v.33 no.3
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• pp.157-166
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• 2021

Three specimens, presumed to be natural hybrids between Rhodeus notatus and R. ocellatus, were collected from Onyangcheon Stream area, Jwabu-dong, Asan-si, Chungcheongnamdo, the Republic of Korea, and morphological and phylogenetic analyses were performed to clearly identify their parent species. The body color of the three natural hybrids was light greenish-brown on dorsal side, and the size of red area on the upper front of the dorsal fin and the outer margin of the anal fin generally showed intermediate characters between the parent species, R. notatus and R. ocellatus. Among the measurement and meristic characters, the ratio of prepectoral length and preanal length in the standard length, and the ratio of snout length, interorbital width, length of caudal peduncle and depth of caudal peduncle in the head length, and the number of longitudinal row scales were analyzed as the unique characters of natural hybrids. In the rag1 gene of nuclear DNA, the three natural hybrids were analyzed to be reflected all the single nucleotide polymorphism sites between R. notatus and R. ocellatus, and in the phylogenetic tree using the cytb gene of mitochondrial DNA, they formed the same genetic clade as R. notatus. Therefore, three specimens, presumed to be natural hybrids analyzed in this study were identified as interspecific hybrids between female R. notatus and male R. ocellatus.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.338-341
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• 2009

"Hwaweon 1" was developed from an interspecific cross between Hwaseongbyeo and a wild species, Oryza rufipogon L. (IRGC 105491) based on marker-aided selection. The recurrent parent "Hwaseongbyeo" is a high grain quality cultivar with medium-maturity. Hwaweon 1 is nearly isogenic to Hwaseongbyeo except a small O. rufipogon introgression on chromosome 8 harboring the gene for grain weight. The preliminary and replicated yield trial was conducted at Chungnam National University in 2004, 2005 and 2006. The local adaptability test was carried out by the National Seed Management Office (NSMO) in 2007 and 2008. This cultivar was registered to NSMO with a cultivar designated as "Hwaweon 1". This cultivar averaged 89 cm in culm length and has a medium growth duration. This cultivar is resistant to stripe virus as the recurrent parent, Hwaseongbyeo. Milled rice of "Hwaweon 1" is translucent and the grain quality traits are comparable to those of the recurrent parent. The yield potential of "Hwaweon 1" in grain is about 7.43 MT/ha at the ordinary fertilizer level about 10% higher than that of Hwaseongbyeo mainly due to increase in grain weight.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.281-285
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• 2005

Pod dehiscence (PD), defined as the opening of pods along both the dorsal and ventral sutures, causes the seed to shatter in the field before harvesting and results in loss of seed yields. However, breeding for resistance to PD is difficult due to the complicated genetic behavior and environmental interaction. The objective of the present research was to analyze the genetic behavior of PD for improving the breeding efficiency of resistance to PD in soybean. PD after oven-drying the sampled pod at $40^{\circ}C$ for 24 hours was the most reliable to predict the degree of PD tested in the field. Keunolkong, a dehiscent parent, was crossed with non-dehiscent parents, Sinpaldalkong and Iksan 10. Using their $F_1\;and\;F_2$ seeds, PD was measured after oven drying the pod at $40^{\circ}C$ for 24 hours. The gene conferring PD behaved in different manners depending on the genetic populations. In the Keunolkong$\times$Sinpaldalkong population, PD seemed to be governed by single major recessive gene and minor genes, while several genes were probably involved in the resistance to pod dehiscence in the Keunolkong$\times$Iksan 10 population. Heritability for PD estimated in F2 population showed over $90\%$ in the two populations. High heritability of PD indicated that selection for resistance to PD should be effective in a breeding program. In addition, genetic mapping of quantitative locus (QTL) for PD in both populations may reveal that genes conferring PD are population-specific.

• Journal of Crop Science and Biotechnology
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• v.10 no.3
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• pp.193-200
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• 2007

Mungbean plants generally have a relatively close canopy, thus a large amount of self-shading can reduce yield due to poor light penetration. Modification of leaflet type can affect leaf canopy and could alter seed yield. Two multiple leaflet mutants were obtained from gamma-ray irradiation and used to study the mode of inheritance related to leaflet types and to evaluate their agronomic features. The cross between large-heptafoliate leaflet with small-pentafoliate leaflet mutants produce all $F_1$ plants with normal trifoliate leaflets. The $F_2$ plants segregated in leaflet size and leaflet number into a 9:3:3:1 ratio of large-trifoliate: large-heptafoliate: small-pentafoliate: small-heptafoliate plants, suggesting that independent loci control leaflet size and leaflet number. Regarding leaflet number, the $F_2$ population can be classified into normal-trifoliate, small-pentafoliate, large-heptafoliate, and small-heptafoliate at the dihybrid ratio of 9:3:3:1. The gene symbols $N_1,n_1$ and $N_2,n_2$ are proposed to represent leaflet number. Since no plant was found with large-pentafoliate leaflets, we hypothesize that the $N_2$ allele expresses pleiotropic effect on both leaflet number and leaflet size. Another possibility is that an additional locus with S and s alleles controls leaflet size and S is tightly linked with $N_2$. The effect of multifoliate leaflet on yield and yield components was evaluated in four mungbean families each with four leaflet isolines under three environments. Averaging across the families and environments, the normal-trifoliate and large-heptafoliate lines gave higher yield than small pentafoliate and heptafoliate ones. These two large leaflet lines also had higher leaf area per plant than the other multifoliate lines. Therefore, the mungbean lines with a greater leaf area, which were likely to intercept more sunlight, gave greater yield. Three AFLP markers that were found to be linked to number of leaflets per leaf, corresponded to the N1 allele of the smallpentafoliate parent.