• Horticultural Science & Technology
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• v.19 no.3
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• pp.329-333
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• 2001

The study was performed to investigate the effect of a plug culture method in the early stage of a potato breeding program. The 105, 200 and 288-cell plug trays were used for raising potato seedlings. The % germination in plug trays ranged between 94 and 96%. Percent tuberization measured at 50 and 60, and 70 days after sowing was the greatest in 105-cell and 200-cell trays, respectively. However, tuberization was most delayed in 288-cell trays. Thus, it is considered that 105-cell tray is the most effective for the selection of early maturing plants. Plant maturity was determined by the morphological characteristics at the seedling stage of stolons cultured in plug trays. Most of seedlings with shorter stolons at seedling stage (1st generation) were the early-maturing, while most of seedlings with longer stolons were the late-maturing at the clonal stage (2nd generation). These results mean that the plant maturity in the early potato breeding program can be effectively grouped by observing the morphological characteristics of stolons after plug culture.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.27-62
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• 1975

These studies were aimed at clarifying whether or not selecting agronomic characteristics of hybrid-rice populations under greenhouse conditions was useful. The selection of two quantitative characteristics, culm length and heading date, and two qualitative characteristics, shattering and awnedness, was very effective, but the flag leaf length and the exsertion of panicle was not consistent, varying from one cross to another.

• Journal of Animal Science and Technology
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• v.53 no.1
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• pp.1-6
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• 2011

This simulation study was performed to investigate the accuracy of the estimated breeding value by using genomic information (GEBV) by way of Bayesian framework. Genomic information by way of single nucleotide polymorphism (SNP) from a chromosome with length of 100cM were simulated with different marker distance (0.1cM, 0.5cM), heritabilities (0.1, 0.5) and half sibs families (20 heads, 4 heads). For generating the simulated population in which animals were inferred to genomic polymorphism, we assumed that the number of quantitative trait loci (QTL) were equal with the number of no effect markers. The positions of markers and QTLs were located with even and scatter distances, respectively. The accuracies of estimated breeding values by way of indicating correlations between true and estimated breeding values were compared on several cases of marker distances, heritabilities and family sizes. The accuracies of breeding values on animals only having genomic information were 0.87 and 0.81 in marker distances of 0.1cM and 0.5cM, respectively. These accuracies were shown to be influenced by heritabilities (0.87 at $h^2$ =0.10, 0.94 at $h^2$ =0.50). According to half sibs' family size, these accuracies were 0.87 and 0.84 in family size of 20 and 4, respectively. As half sibs family size is high, accuracy of breeding appeared high. Based on the results of this study it is concluded that the amount of marker information, heritability and family size would influence the accuracy of the estimated breeding values in genomic selection methodology for animal breeding.

• Proceedings of the Korean Society of Crop Science Conference
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• 1996.05a
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• pp.16-17
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• 1996

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.180-186
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• 1994

Lipoxygenase activity of soybean seeds of approximately 507 genotypes as well as its inheritance and selection efficiency in early breeding generation was measured in the Department of Agronomy, Seoul National University to facilitate breeding for low lipoxygenase activity of soybean. Average seed lipoxygenase activity of 507 cultivars and strains was 350 unit (unit: $\Delta$0.01 /min. /mg at 234nm) and ranged from 50 to 670 unit. There was no difference in mean lipoxygenase activity according to apparent seed characters such as seed coat and embryo color. But early mature soybean genotypes had fairly low lipoxygenase activity. Lipoxygenase activity was inherited quantitatively, in which additive effect was greater than dominant one and proportion of gene with positive effects was similar to that with negative ones. Estimated narrow- and broad-sense heritabilities were 0.78 and 0.86 for lipoxygenase activity, respectively. Heritability measured from selection in early breeding lines for high or low lipoxygenase activity was 64~76% or 54~62%, respectively. And selection for high lipoxygenase activity increased by 29.7~44.7%, whereas that for low ones decreased by 21.8~27.3%, respectively, when compared to random population. Clear effect in selecting of lipoxygenase activity was present in early generation.

• Journal of Sericultural and Entomological Science
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• v.53 no.1
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• pp.55-60
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• 2015

Melittin is the main component of Bee Venom and has antibacterial activity against several bacteria. To produce the melittin antimicrobial peptide, we constructed transgenic silkworm that expressed melittin gene under the control BmA3 promoter using piggyBac vector. The use of the 3xP3-driven EGFP cDNA as a marker allowed us to rapidly distinguish transgenic silkworm. Mixtures of the donor vector and helper vector were micro-injected into 300 eggs of bivoltin silkworms, Baegokjam. In total, 131 larvae (G0) were hatched and allowed to develop into moths. The resulting G1 generation consisted of 36 broods, and we selected 4 broods containing at least 1 EGFP-positive embryo. The rate of successful transgenesis for the G1 broods was 11%. We identified 12 EGFP-positive G1 moths and these were backcrossed with wild-type moths. With the aim of identifying a melittin as antimicrobial peptide, we investigated the Radical diffusion Assay (RDA) and then demonstrated that melittin possesses high antibacterial activities against gramnegative bacteria.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.90-96
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• 1990

The study was intended to clarify the direct and indirect effects of agronomic and chemical characters influencing upon yield in tobacco breeding. The eight parents and a set of 28 crosses of F$_1$'s and F$_2$'s were used as materials, and planted on two different cultivated systems, i.e., oriental's and burley systems, during 1986 to 1988 at Daegu Experiment Station. Four characters which were leaf length, leaf width, days to flowering and number of leaves per plant influenced the highly direct effects upon the leaf yield, but five chemical components were expressed as low effects. In indirect effects, leaf length, days to flowering and total nitrogen had the high indirect effects influencing upon leaf yield via the other characters. Accordingly, the results were discussed with a conclusion that the selection should be based on the data from leaf length, days to flowering, leaf width and number of leaves per plant.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.165-171
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• 2019

Marker-assisted backcrossing (MABC) is useful for selecting an offspring with a highly recovered genetic background for a recurrent parent at early generation to various crops. Moreover, marker-assisted backcrossing (MABC) along with marker-assisted selection (MAS) contributes immensely to overcome the main limitation of the conventional breeding and it accelerates recurrent parent genome (RPG) recovery. In this study, we were employed to incorporate rin gene(s) from the donor parent T13-1084, into the genetic background of HK13-1151, a popular high-yielding tomato elite inbred line that is a pink color fruit, in order to develop a rin HK13-1084 improved line. The recurrent parent genome recovery was analyzed in early generations of backcrossing using SNP markers obtained from genotyping-by-sequencing analysis. From the $BC_1F_1$ and $BC_2F_1$ plants, 3,086 and 4868 polymorphic SNP markers were obtained via GBS analysis, respectively. These markers were present in all twelve chromosomes. The background analysis revealed that the extent of RPG recovery ranged from 56.7% to 84.5% and from 87.8% to 97.8% in $BC_1F_1$ and $BC_2F_1$ generations, respectively. In this study, No 5-1 with 97.8% RPG recovery rate among $BC_2F_1$ plants was similar to HK13-1151 strain in the fruit shape. Therefore, the selected plants were fixed in $BC_2F_2$ generation through selfing. MAS allowed identification of the plants that are more similar to the recurrent parent for the loci evaluated in the backcross generations. MABC can greatly reduce breeding time as compared to the conventional backcross breeding. For instance, MABC approach greatly shortened breeding time in tomato.

• Journal of Plant Biotechnology
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• v.38 no.2
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• pp.125-129
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• 2011

Environmental risk assessment (RA) is essential prior to the environmental release of GM crops. RA, however, costs at least 7 to 15 million US dollars and requires several years to complete field tests. Therefore, it is strongly suggested that developers of GM crops must consider all criteria for RA at the beginning stage of the development if it aims for commercialization. Previous review papers have pointed out that the "death valley" for the commercialization of GM crops is the screening stage of early GM events since many candidates are given up due to insufficient data on the molecular characterization of a GM event such as inserted gene's copy number, position of inserted site of a chromosome, flanking sequence of recombinant T-DNA, rearrangement of chromosome, and knock out of endogenous gene of host plant. Recently, Rural Development Administration (RDA) in South Korea has launched a Grand National Project named as "Next Generation of BioGreen 21 Project" from 2011 to 2020 and research funding for the development of global GM crops has been allocated to accelerate the commercialization of GM crops. In this regard, I strongly suggest that researchers involved in the development of GM crops for commercialization must conduct RA by themselves at the screening stage of pre-GM event based on the data for molecular characterization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.499-506
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• 1993

The contents of sulfur, sulfur-containing protein and amino acids of soybean seeds of 518 genotypes as well as their inheritance and selection efficiency in early breeding generation were measured to facilitate breeding for soybean with high sulfur-containing amino acids. Average seed sulfur content of 518 cultivars was 0.33%, and ranged from 0.20 to 0.45%, and that of 30 wild soybeans was 0.35%, and ranged form 0.19 to 0.62%. Correlation coefficients between seed sulfur content and sulfur-containing protein and amino acids were 0.924$^{**}$ and 0.974$^{**}$, respectively. Seed sulfur content was tended to be high in soybean genotypes with late maturity, seed coat bloom, or green cotyledon. Sulfur content had -0.312$^{**}$ correlation coeficient with sugar content and -0.384$^{**}$ with 100 seed weight. Seed sulfur content was inherited quantitatively, in which additive effect was greater than dominant one, and proportion of genes with positive effects was similar to those with negative ones. Estimated narrow- and broad-sense heritabilities were 0.75 and 0.88 for seed sulfur content, respectively. Heritability measured from selection in early breeding lines for high or low seed sulfur content was 60～62.5% or 50～62,5%, respectively. And selection for high sulfur content increased by 14.7～18.8%, whereas that for low one decreased by 8.8～15.6%, when compared to that of random population. Therefore selection in early generation seemed to be clearly effective.