• Horticultural Science & Technology
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• v.29 no.4
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• pp.336-344
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• 2011

Using the abundant available information about the tomato genome, we developed DNA markers that are linked to disease resistant loci and performed marker-assisted selection (MAS) to construct multi-disease resistant lines and varieties. Resistance markers of Ty-1, T2, and I2, which are linked to disease resistance to Tomato yellow leaf curl virus (TYLCV), Tomato mosaic virus (ToMV), and Fusarium wilt, respectively, were developed in a co-dominant fashion. DNA sequences near the resistance loci of TYLCV, ToMV, and Fusarium wilt were used for primer design. Reported candidate markers for powdery mildew-resistance were screened and the 32.5Cla marker was selected. All four markers (Ty-1, T2, I2, and 32.5Cla) were converted to cleavage amplification polymorphisms (CAPS) markers. Then, the CAPS markers were applied to 96 tomato lines to determine the phenetic relationships among the lines. This information yielded clusters of breeding lines illustrating the distribution of resistant and susceptible characters among lines. These data were utilized further in a MAS program for several generations, and a total of ten varieties and ten inbred lines were constructed. Among four traits, three were introduced to develop varieties and breeding lines through the MAS program; several cultivars possessed up to seven disease resistant traits. These resistant trait-related markers that were developed for the tomato MAS program could be used to select early stage seedlings, saving time and cost, and to construct multi-disease resistant lines and varieties.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.20-20
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• 2022

A traditional wheat breeding program needs more than 12-13 years to develop a new cultivar. In recent years, 'Speed breeding (SB)' system, which uses extremely extended photoperiod (22 h), enabled up to 4-6 generations of spring wheat per year. However, since almost 70% of wheat cultivars are winter type, and over 95% of total cultivation area is for winter wheat in Korea, optimized vernalization treatment was essential for improving the SB system. Several vernalization temperatures and durations were tested with various genotypes, and the 4 weeks of 8-10 ℃ vernalization treatment was the most effective to develop 4 generations per year, for both spring and winter type wheat cultivars. This 'Speed vernalization (SV)' system followed by SB, allowed developing a new F₆ recombinant inbred lines (RILs) within 2 years. Among the 184 RILs, which derived from a cross between Jokoyung and Joongmo2008, two outstanding lines were selected for yield trial test, and then named Milyang52 and Milyang53. Compared to the traditional wheat breeding program, over 60% of the time was saved to develop these two lines. Marker-assisted selection and backcross were also combined with the SV system. YW3215-2B-1 (Jokoyung*3/Gamet), which has similar agronomic traits with Jokyoung and the same Glu-B1 allele with Garnet, was developed within 2.5 years. Thus, the SV system combined with molecular breeding technology would help breeders to make a new cultivar with less time and high efficiency.

• Proceedings of the Korean Society of Crop Science Conference
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• 1997.10a
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• pp.9-10
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• 1997

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.383-390
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• 2014

The multiplex PCR system including six microsatellites from Haliotis discus hannai, consisting of dinucleotide and trinucleotide repeat units, is developed. The six loci were coamplified in a single reaction employing dye-labeled primers. Alleles from these loci were sized using an internal standard by automated sample processing in an ABI3100 Genetic Analyser. Amplified alleles in profiles containing selected microsatellites were typed clearly, providing easily interpretable results. In this results suggest that the presented multiplex PCR system may be a useful tool in a selective breeding program of H. discus hannai in which genetic identification will allow different genotypes to be reared together from fertilization. This should have a great impact as it will make selective breeding more efficient. Moreover, it will be useful in a variety of applications, including strain and hybrid identification, parentage assignment, pedigree reconstruction, estimating genetic diversity and/or inbreeding.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.974-981
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• 2021

The aim of this study was to evaluate genetic parameters of growth traits for improving selective breeding in olive flounder Paralichthys olivaceus produced in April 2019. The total length and body weight at 11-, 18-, and 22-months-old were measured for 7,479, 2,831 and 1,904 individuals, respectively. Since 2004, we have been conducting a selective breeding program to improve growth traits in the olive flounder. Data were analyzed using the restricted maximum likelihood method using the multiple traits animal model. The effect of sex and production period showed significant differences in all traits (P<0.05). The heritability of all traits was 0.428-0.520, which is relatively high by measurement month. Therefore, it is considered that individual selection will be more advantageous than family selection. However, to maintain an appropriate degree of inbreeding and genetic diversity for future generations, it is necessary to consider family selection adequately. Results of the correlation analysis between the same traits according to the measurement period indicated that considering production costs such as feed cost, selection at 18-months-old will be advantageous. Olive flounder is a major aquaculture species in Korea, and continuous selective breeding research is essential to improve productivity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.67-67
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• 2017

We developed the breeding materials with diverse grain size and shape in japonica rice. Grain size and shape are important factors affecting consumer preference and choice. However, most of Korean japonica rice cultivars have small, short, and round grain. To diversify the grain size and shape of japonica rice, we conducted the breeding program using donor parents, Jizi1560 and Jizi1581. Jizi1560 and Jizi1581 are japonica germplasm with extremely large grain. Four crosses between the each donor parents and high yielding japonica rice cultivars, Deuraechan and Boramchan, were constructed and then anther culture method was applied. We obtained 290 doubled-haploid (DH) lines with appropriated morphological traits and selected 91 DH lines with diverse grain size and shape. The grain related-traits of the selected DH lines showed a higher diversity when compared with 319 cultivars developed by NICS (264 japonica, 13 black, and 32 Tongil type cultivars). We designated the selected DH lines, four parents, and Daeripbyeo 1, large grain japonica cultivar, as the breeding materials for further analysis. The breeding materials were classified into five groups, A to E, based on the grain-related traits. Group A (including Jizi1581) and Group B (including Daeripbyeo 1) showed similar grain width, whereas Group A exhibited longer grain length and heavier grain weight. Group C (including Deuraechan and Boramchan) showed shorter and rounder grain shape and smaller grain size than any other groups. Group D including solely Jizi1560 had extremely large grain, such as the longest grain length, width, and thickness and heaviest grain weight. Group E including only two DH lines had long and slender grain shape, so that showed the highest ratio of length to width. The grain size and shape of the breeding materials exhibited beyond the characteristics of previously developed Korean japonica cultivars. The breeding materials will be applied in the breeding programs to diversify the grain size and shape of japonica rice.

• Molecules and Cells
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• v.21 no.2
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• pp.284-293
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• 2006

Even though Ac/Ds gene-tagging systems have been established in many higher plants, maize is the only major plant in which short-distance transposition of Ac/Ds has been utilized to probe gene function. This study was performed to evaluate the efficiency of obtaining new alleles and functional revertants from Ds insertion loci in rice. By analyzing 1,580 plants and the progeny of selected lines, the insertion sites and orientations of Ds elements within 16 new heritable alleles of three rice loci were identified and characterized. Intragenic transposition was detected in both directions from the original insertion sites. The closest interval was 35 bp. Three of the alleles had two Ds elements in cis configuration in the same transcription units. We also analyzed the excision footprints of intragenic and extragenic transpositions in Ds-inserted alleles at 5 loci. The 134 footprints obtained from different plants revealed predominant patterns. Ds excision at each locus left a predominant footprint at frequencies of 30-75%. Overall, 66% of the footprints were 7-bp additions. In addition, 16% of the excisions left 0-, 3-, 6-, and 9-bp additions with the potential of conserving reading frame.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.147-158
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• 2005

The purpose of this study was to find out the effects that daughters' incomplete lactation records affect sire's breeding values through genetic evaluation using RRTDM(random regression test-day model). First, we estimated genetic parameters and breeding values on sires having complete lactation records of daughter by RRTDM, second, we changed complete lactation records of specific sires into incomplete records by various methods. Third, the breeding values were compared between complete and incomplete records. Finally, this study aimed to find out the methods to minimize the estimation errors of young bulls' breeding values. Data used in this study were collected from the dairy herd improvement program, and a total of 97,562 records were composed of 10,929 first parity with both parents known, since 1999. Breeding values on the daughters from randomly chosen sires were calculated and compared with among 90 day, 150day, and 200 day's incomplete records. For milk yields, sire's ranks of breeding values used by complete lactation records were very different from sire's ranks of breeding values obtained by incomplete lactation records(Rank_90 cut, 150cut, 200 cut).The differences were also obtained between complete lactation records(per305_full) and incomplete lactation record (per_90 cut, 150cut, 200 cut) in breeding values regarding persistency. Especially, the differences between per_90 cut and per305_full were very large(from 1.8 kg to 145kg).

• 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.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.421-428
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• 2020

Tamarind (Tamarindus indica L.) is one of the multipurpose tree species distributed in the tropical and sub-tropical climates. It is an important fruit yielding tree that supports the livelihood and has high social and cultural values for rural communities. The vegetative, reproductive, qualitative, and quantitative traits of tamarind vary widely. Characterization of phenotypic and genetic structure is essential for the selection of suitable accessions for sustainable cultivation and conservation. This study aimedto examine the genetic relationship among the collected accessions of sweet, red, and sour tamarind by using Random Amplified Polymorphic DNA (RAPD) primers. Nine accessions were collected from germplasm gene banks and subjected to marker analysis. Fifteen highly polymorphic primers generated a total of 169 fragments, out of which 138 bands were polymorphic. The polymorphic information content of RAPD markers varied from 0.10 to 0.44, and the Jaccard's similarity coefficient values ranged from 0.37 to 0.70. The genetic clustering showed a sizable genetic variation in the tamarind accessions at the molecular level. The molecular and biochemical variations in the selected accessions are very important for developing varieties with high sugar, anthocyanin, and acidity traits in the ongoing tamarind improvement program.