• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1247-1253
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• 2003

Selection for increased milk production in dairy cows has often resulted in a higher incidence of disease and thus incurred a greater health costs. Considerable interests have been shown in breeding dairy cattle for disease resistance in recent years. This paper discusses the limitations of breeding dairy cattle for genetic resistance in six parts: 1) complexity of disease resistance, 2) difficulty in estimating genetic parameters for planning breeding programs against disease, 3) undesirable relationship between production traits and disease, 4) disease as affected by recessive genes, 5) new mutation of the pathogens, and 6) variable environmental factors. The hidden problems of estimating genetic and phenotypic parameters involving disease incidence were examined in terms of categorical nature, non-independence, heterogeneity of error variance, non-randomness, and automatic relationship between disease and production traits. In light of these limitations, the prospect for increasing genetic resistance by conventional breeding methods would not be so bright as we like. Since the phenomenon of disease is the result of a joint interaction among host genotype, pathogen genotype and environment, it becomes essential to adopt an integrated approach of increasing genetic resistance of the host animals, manipulating the pathogen genotypes, developing effective vaccines and drugs, and improving the environmental conditions. The advances in DNA-based technology show considerable promise in directly manipulating host and pathogen genomes for genetic resistance and producing vaccines and drugs for prevention and medication to promote the wellbeing of the animals.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.234-234
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• 2022

Gene-editing is currently one of the most popular technologies in recent years. Development of the new crop using the gene editing have advantage of improved accuracy and efficiency compared with conventional breeding. Soybean (Glycine max L.) is one of the most important crops worldwide used as food and forage. We tried to establish a system for breeding improvement of soybean through gene-editing technology. For the gene-editing system of soybean, i) selection of efficiency gRNA of targeted gene, ii) efficient genetic transformation of the selected gRNA, iii) selection of trans-clean mutant is essential. First of all, we investigated the selection conditions of gRNA with high editing efficiency of targeted gene using isolated protoplast of soybean. Furthermore, we performed the Agrobacterium-mediated genetic transformation of various soybean cultivars. We identified the tissue culture ability in 23 soybean cultivars for genetic transformation of soybean. The six cultivars with high tissue culture ability were selected and confirmed the transgenic plants in four cultivars. Finally, we established a speed-breeding system as a powerful tool for the fast selection of trans-clean mutants from transgenic plants. Our laboratory will provide the valuable system for improvement of soybean by the gene-editing technology.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.7
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• pp.905-909
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• 2001

Three groups of wethers viz. Jamunapari ♂$\times$Black Bengal ♀ (JBB), Selected Black Bengal ♂$\times$Selected Black Bengal ♀ (SBB) and Random Black Bengal ♂$\times$Random Black Bengal ♀ (RBB) of 1 year old were evaluated for pre-slaughter traits and carcass characteristics. The correlations between pre-slaughter traits and carcass traits were computed. It was found that the preslaughter weights of JBB and SBB were almost similar in yielding hot and chilled carcass as well as dressing percentage (DP). RBB wethers were lighter (p<0.05) than JBB and SBB in pre- and post-slaughter weights and also inferior (p<0.05) in DP. SBB wethers were found to produce more visceral fat compared to JBB and RBB. Other variety meats appeared erratic in yield.l. Correlations were compared by Z statistic among three genetic groups and the value of Z did not differ (p>0.05) between groups.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.161-171
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• 2020

Direct seeding is one of the rice seedling establishment methods that is increasingly being practiced by farmers to save labor and reduce costs. However, this method often causes poor germination under flooding conditions after sowing. In this study, we developed japonica elite lines with quantitative trait loci (QTL) associated with anaerobic germination (AG) tolerance to overcome poor germination and seedling establishment in wet direct seeding. The QTL introgression lines were developed from a cross between weedy photoblastic rice as the AG donor and the Nampyeong variety via phenotypic and genotypic selection. Compared to Nampyeong, the survival rates of the selected lines were improved by approximately 50% and 240% under field and greenhouse conditions, respectively. To improve selection efficiency by marker assisted selection, the QTL markers associated with AG tolerance were converted to cleaved amplified polymorphic sequence markers designed based on next-generation sequence analysis. These lines retained similar agronomic traits and yield potential to the parent, Nampyeong. Among these lines, we selected the most promising line, which exhibited high survival rate and good agricultural traits under flooding conditions and named the line as Jeonju643. This line will contribute to breeding programs aiming to develop rice cultivars adapted to wet direct seeding. This study demonstrates the successful application of marker-assisted selection to targeted introgression of anaerobic genes into a premium quality japonica rice variety.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.397-406
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• 2015

Quantitative traits are mostly controlled by a large number of genes. Some of these genes tend to have a large effect on quantitative traits in cattle and are known as major genes primarily located at quantitative trait loci (QTL). The genetic merit of animals can be estimated by genomic selection, which uses genome-wide SNP panels and statistical methods that capture the effects of large numbers of SNPs simultaneously. In practice, the accuracy of genomic predictions will depend on the size and structure of reference and training population, the effective population size, the density of marker and the genetic architecture of the traits such as number of loci affecting the traits and distribution of their effects. In this review, we focus on the structure of Hanwoo reference and training population in terms of accuracy of genomic prediction and we then discuss of genetic architecture of intramuscular fat(IMF) and marbling score(MS) to estimate genomic breeding value in real small size of reference population.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.2
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• pp.130-132
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• 2002

The new burley tobacco variety, KB 301, was developed by the cross combination ’(Ky 17 x TI 1068)F$_4$ x TC 613’. The modified pedigree breeding method was used in the selection procedures. The agronomic traits and chemical constituents of KB 301 were very similar to those of Burley 21. But KB 301 had significantly higher content of total DVT than Burley 21. KB 301 was also resistant to black shank, TMV and PVY.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.6-6
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• 2017

In recent decades, scientists have had great success identifying specific loci that contribute to the variability of agronomically important phenotypes. But, while loci of large-effect remain the simplest and most commonly identified in genomic studies, mounting evidence suggests that a substantial proportion of crop evolution is driven by loci of small effect. In this talk, results demonstrating that large-effect loci are not the primary driver of maize evolution will be presented, along with a new method to test quantitative traits for evidence of past selection. By applying this this method to a maize breeding population, we show that agronomic traits important for breeding are often dictated by loci of small effect. The implications of these results for driving crop improvement will be discussed, including their potential application to breeding protocols that anticipate global climate change.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.293-299
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• 2015

High temperature is one of major environmental stress. Heat tolerance managing is difficult through the phenotypic selection, so marker assistant selection (MAS) using molecular markers like as RAPD, SSR etc. was tried to select useful traits for heat tolerance. Fourteen SSR markers reported by previous research were selected for this research. We tried to evaluate 14 SSR markers for MAS using 31 useful wheat resources including 24 crossing line from Turkey, six Korean wheat cultivars and Chinese spring. The average of the number of alleles and PIC values in this study were 6.14 and 0.64, respectively. Two major clades and four sub clades were grouped by phylogenetic tree using UPGMA. Four Korean wheat cultivars were distinct from other Turkey resources in the phylogenetic dendrogram. From the results, we expected that these markers were able to adapt to screening wheat genotyping for heat tolerance.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1415-1419
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• 2018

Objective: To estimate effect of single nucleotide polymorphisms on the intramuscular fat content (IMF) of Hungarian Simmental bulls. Methods: Genotypes were determined on high-density Illumina Bovine DNA Chip. After slaughtering of animals, chemical percentage of intramuscular fat was determined from longissimus dorsi muscle. A multi-locus mixed-model was applied for statistical analyses. Results: Analyses revealed four loci (rs43284251, rs109210955, rs41630030, and rs41642251) to be highly associated ($-{\log}_{10}P$>12) with IMF located on chromosome 1, 6, 13, and 17, respectively. The frequency of their minor alleles was 0.426, 0.221, 0.162, and 0.106. Conclusion: The loci above can be useful in selection programs and gives the possibility to assist selection by molecular tools.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.2
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• pp.111-114
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• 1993

This study was carried out to obtain the basic information for breeding of aromatic burley tobacco, and to select the breeding lines with higher DVT (diterpenes $\alpha$-and $\beta$-4, 8, 13-duvatriene-1, 3-diols) and cis-abienol (Z-labda-12, 14-diene-8$\alpha$-ol) concentrations. The parental genotypes used to develop the Fl and Fl generations were Burley 21, Ky 17, male-sterile(MS) NC 107, TC 612, TC 613, Va 509 and Tl 1068. To estimated the modes of inheritances of DVT and cis-abienol known as the flavor and aroma compounds, the method of thin - layer chromatography (TLC) was used. It was considered that TLC procedure being relatively simple and reproducible in the selection of the breeding lines with higher DVT and cis-abienol. DVT was present in all of parents except MS NC 107, but cia-abienol presented only in Tl 1068. It was estimated from the TLC analysis of parents and Fl's that DVT and cis-abienol were each inherited by dominant gene or genes. But it was less clear to determine the presence or not of sucrose ester(SE) on the TLC plate. The eleven plants which had burley leaf color and also estimated to have DVT and cis-abienol were selected in the F2 population of three combinations.