• 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 Crop Science and Biotechnology
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• v.11 no.3
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• pp.171-176
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• 2008

The agronomic traits, such as days to flowering and maturity, plant height, 100-seed weight and seed filling period, are quantitatively inherited and important characters in soybean(Glycine max L. Merr.). A total of 126 $F_5$ recombinant inbred lines(RILs) developed from the cross of PI 171451$\times$Hwaeomputkong were used to identify quantitative trait loci(QTLs) for days to flowering(FD), days to maturity(MD), plant height(PH), 100-seed weight(SW), number of branches(NB) and seed filling period(FP). A total of 136 simple sequence repeat(SSR) markers segregated in a RIL population were distributed over 20 linkage groups(LGs), covering 1073.9 cM of the soybean genome with the average distance between adjacent markers of 7.9 cM. Five independent QTLs were identified for FD, three for MD, two for PH, three for SW, one for NB and one for FP. Of these, three QTLs were related to more than two traits of FD, MD, PH, NB and FP and mapped near the same positions on LGs H and O. Thus, these traits could be correlated with biologically controlled major QTLs in this soybean RIL population.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.431-438
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• 2010

Anthers of sweet pepper $F_1$ cultivar 'Special' were cultured on Dumas De Vaulx (C medium), supplemented with $0.1mgL^{-1}$ 2, 4-D and $0.1mg{\cdot}L^{-1}$ kinetin with 3% sucrose, and 0.32% phytagel. The calluses obtained were further sub-cultured on Murashige and Skoog (MS) medium without growth regulators for regeneration. Regenerated plantlets were grown in plastic pots under plastic house and characterized their cytological and morphological characters in spring, 2008. Twenty percent plantlets were identified as haploid plants after chromosome and ploidy analysis. Haploid plants contained 12 chromosomes, high stomatal density with small stomatal length as compared to diploid plants. Stomatal length in haploids was 23.3% smaller than diploids. Haploid plants were characterized as small leaf and petiole size, poor vigor, thin stem and short plant height, short internodes and small flower buds, fruit size and fruit weight as compared to diploid plants and most of the haploid fruits were seedless. SP55, SP62, SP68, SP72 and SP77 are found high yielding double haploids with high total soluble content (8.6, 8.7, 9.2, 9.1 and $9.8^{\circ}Brix$, respectively) and desirable fruit shape, and recommended them to exploit as inbred lines for heterosis breeding.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.454-462
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• 2018

Yield and grade are the key factors that affect production value of peanut. The objective of this study was to identify QTLs for pod yield, hundred-seed weight, and total sound mature kernel (TSMK). A total of 90 recombinant inbred lines, derived from Tamrun OL07 and a breeding line Tx964117, were used as a mapping population and planted in Brownfield and Stephenville, Texas. A genetic map was developed using 1,211 SNP markers based on double digest restriction-site associated DNA sequencing (ddRAD-seq). A total of 10 QTLs were identified above the permutation threshold, three for yield, three for hundred-seed weight and four for TSMK, with LOD score values of 3.7 - 6.9 and phenotypic variance explained of 12.2% - 35.9%. Among those, there were several QTLs that were detected in more than one field experiment. The commonly detected QTLs in this study may be used as potential targets for future breeding program to incorporate yield and grade related traits through molecular breeding.

• Reproductive and Developmental Biology
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• v.35 no.3
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• pp.247-250
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• 2011

The objective of this study was to find out candidate genes associated with litter size trait in pigs of inbred Large Yorkshire and Landrace populations. 86 sows were screened for candidate genotypes along with litter size data recordings. Association of litter size with genotypes of candidate genes were investigated to verify the usefulness of each gene's genotypes as markers for the trait. For the lines of Large Yorkshire, PRLR3 and RBP4 genes were genotyped. Frequency distribution of PRLR3 with genotypes AA, AB and BB were each 0.14, 0.44 and 0.42. And the average litter size by PRLR3 genotypes were 8.83, 10.81 and 10.70 piglets per litter, the average estimated breeding values of which were 0.243, 0.332, 0.365, respectively for AA, AB and BB genotypes. Genotypic frequencies of RBP4 by AA, AB and BB genotypes were 0.10, 0.44 and 0.46. The average litter size by genotypes of RBP4 were 10.40, 10.57 and 10.35 piglets per litter and their corresponding average estimated breeding values were 0.451, 0.353 and 0.261, respectively for genotypes AA, AB and BB. Significance in differences among genotypes were not observed, but B allele of RBP4 seems to be associated with litter size. In Landrace lines, frequencies of RBP4 genotypes, AA, AB and BB were 0.29, 0.55 and 0.16. And the average litter size of these genotypes were 10.50, 11.08 and 11.00 piglets per litter. The corresponding averages of estimated breeding values of each genotypes were 0.172, 0.135 and 0.104. In Landrace lines, allele A was more likely to be associated with litter size, even if differences among average litter size were not significant. We conclude that genotyping of two candidate genes is a helpful tool to identify genetic potentials of litter size in pigs.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.9-18
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• 2002

A total of 31 C. chinense lines selected from 2000 screening were tested again for resistance to P. capsid but resistance was not found in tile lines. A total of 26 selections from Korean land races tested 2001 spring were tested again for resistance to P. capsici, KC180, KC230, KC195 and KC194 showed moderate resistance to P. capsid. However, it was apparent on the basis of horticultural characteristics that KC180 and KC230 had been naturally crossed with AC2258 and CM334, respectively. CM334 and AC2248 seed lots that were increased in different years were taken out and tested for resistance to improve their genetic purity because the resistant genetic resources have been showing some off-types in tile population. Off-types began to be found in 1992 seed lots and tile proportion and degree of tile offs was increasing with time up to 2001. Plants true to the type in 1992 seed lots were selected and their inbred seeds were mass produced in a net cage in the greenhouse. AC2258 included in the experiment together was uniform. In 1995 seed lots of CM334, plants with resistance to P. capsici and low or no number of lateral branching at cotyledonary axil, although they were off from tile original CM334, were found and selection was applied to breed lines fixed in tile characters.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.3
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• pp.205-211
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• 2005

This study was carried out to construct cold-tolerance characteristics. The RILs were developed from progenies of a cross between cold-susceptible Tongil-type rice variety, Milyang 23 and cold-tolerant Japonica rice variety, Stejaree 45 by single seed descent methods. The 175 RILs $(F_8)$ were evaluated for cold tolerance traits by field screening under cold-water irrigation. Frequency distribution of RILs in leaf discoloration, heading delay, culm length reduction and number of spikelets reduction displayed nearly normal distributions with transgressive segregations to either side of parents, while the spikelet fertility reduction and panicle exsertion at low-temperature showed the more or less skewed continuous distribution toward the susceptible parent. Higher heritabilities over $60\%$ were observed in leaf discoloration, spikelet fertility reduction, panicle exsertion, while relatively lower heritabilities less than $40\%$ were observed in culm length reduction, number of spikelets reduction and grain yield reduction. Some cold-tolerance RILs were selected effectively by cold water irrigation, which are expected to be good materials in breeding program for cold tolerance.

• Molecules and Cells
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• v.24 no.1
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• pp.83-94
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• 2007

During monocarpic senescence in higher plants, functional stay-green delays leaf yellowing, maintaining photosynthetic competence, whereas nonfunctional stay-green retains leaf greenness without sustaining photosynthetic activity. Thus, functional stay-green is considered a beneficial trait that can increase grain yield in cereal crops. A stay-green japonica rice 'SNU-SG1' had a good seed-setting rate and grain yield, indicating the presence of a functional stay-green genotype. SNU-SG1 was crossed with two regular cultivars to determine the inheritance mode and identify major QTLs conferring stay-green in SNU-SG1. For QTL analysis, linkage maps with 100 and 116 DNA marker loci were constructed using selective genotyping with $F_2$ and RIL (recombinant inbred line) populations, respectively. Molecular marker-based QTL analyses with both populations revealed that the functional stay-green phenotype of SNU-SG1 is regulated by several major QTLs accounting for a large portion of the genetic variation. Three main-effect QTLs located on chromosomes 7 and 9 were detected in both populations and a number of epistatic-effect QTLs were also found. The amount of variation explained by several digenic interactions was larger than that explained by main-effect QTLs. Two main-effect QTLs on chromosome 9 can be considered the target loci that most influence the functional stay-green in SNU-SG1. The functional stay-green QTLs may help develop low-input high-yielding rice cultivars by QTL-marker-assisted breeding with SNU-SG1.

• The Plant Pathology Journal
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• v.19 no.2
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• pp.111-116
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• 2003

Turnip mosaic Potyvirus (TuMV) and Ribgrass mosaic Tobamovirus (RMV) are major viruses infecting crucifer crops in Korea. RMV-FG22 was isolated from oriental cabbage. TuMV isolates were TuMV-CA7 from oriental cabbage, TuMV-TU and TuMV-TU2 from turnip, TuMV-RA from rape, TuMV-ST from stock, and TuMV-R9 from radish. The six isolates of TuMV were classified by symptom expression in inbred lines of crucifers. TuMV-CA7 and TuMV-TU isolates infected mostly oriental cabbages; TuMV-ST, TuMV-TU2, and TuMV-R9 infected radishes; and TuMV-RA infected both oriental cabbages and radishes. Crops used in six combinations of mixed infections were 'Tambok' cultivar resistant to TuMV,'SSD63' susceptible inbred line of oriental cabbage, pure line of leaf mustard, and‘Daeburyungyeorum’cultivar of radish. External symptoms in 'Tambok' and radish by each of the six single infections of TuMV showed similar results by bioassay. Synergistic response of necrotic death occurred within 1 week after inoculation in all combinations mixed with TuMV and RMV-FG22 on leaf mustard. In oriental cabbage 'SSD63' , synergism of necrosis occurred in four TuMV isolates, but not in TuMV-ST and TuMV-R9. In oriental cabbage 'Tambok' , synergism was expressed only in two combinations of RMV-FG22+TuMV-CA7 and RMV-FG22+TuV-TU, but other combinations had the same symptoms produced by RM-FG22. In radish‘Daeburyungyeorum’, only mild mosaic symptoms were induced by combinations of RMV-FG22+TuMV-CA7, RMV-FG22+TuMV-TU, RMV-FG22+TuMV-RA, and RMV-FG22+TuMV-R9. Mosaic and severe mosaic were induced in combinations of RMV-FG22 +TuMV-TU2 and RMV-FG22+TuMV-ST, respectively.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.917-921
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• 2014

'Hei-G' is a new tomato cultivar originating from the cross of two inbred lines, the maternal plant TKUI-3 separated from 'Kame' in 2007, and the paternal plant AL-1 developed by pedigree breeding. The new cultivar was registered as 'Hei-G' named 'JTB026 (Jeonnam-2)' based on characteristics and yield trials carried out in the spring of 3 years, from 2010 to 2012. 'Hei-G' is an indeterminate type with strong plant vigor. The fruit is round and the ripening fruit is blackish red. The average fruit weight of 'Hei-G' is about 43.4 g, and its marketable yield is $4,944kg{\cdot}10a^{-1}$. The lycopene content of 'Hei-G' ($11.8mg{\cdot}100g^{-1}$) is higher than that of other tomatoes (e.g., cv. Rapido, 3.1 mg). In addition, 'Hei-G' is suitable for environment-friendly protected cultivation because of its resistance to powdery mildew.