• Korean Journal of Poultry Science
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• v.16 no.2
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• pp.61-71
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• 1989

The purposes of this study were to investigate the genetic variations by backcrossing in commercial chickens. Backcrossing was carried out successively back to parent stock (P.S). Heritabilities and genetic correlation coefficients were estimated to verify the genetic variations. The data obtained from a breeding programme with commercial chickens (I strain) were collected from 1955 to 1987 at Poultry Breeding Farm, Seoul National University. Data came from a total of 1230 female offspring. The results obtained are summarized as follows： 1. The general performance ($Mean\pmStandard deviation$) of each trait was $663.94\pm87.11$g for 8 weeks body weight, $1579.1\pm155.43$g for 20 weeks body weight, $2124.1\pm215.3$g for 40 weeks body weight, $2269.1\pm242.94$g for 60 weeks body weight, $168.43\pm12.94$ day for a9e at sexual maturity (SM), $214.52\pm29.82$ eggs , for total egg number to 60 weeks of age (TEN), $61.45\pm3.48$ g for average weight (AEW), $13180.7\pm1823.22$ g for total egg mass to 60 weeks of age(TEM). All traits, except 10 weeks body weight and AEW, were significant for the degrees of backcross (p＜0.01). 2. The pooled estimates of heritabilities derived from the sire, dam and combined variance components were 0.47~0.52 for age at sexual maturity (SM), 0.07~0.37 for total egg number (TEN), 0.40~0.54 for average egg weight (AEW), 0.18~0.27 for total egg mass (TEM). High heritability estimates were found for SM and AEW. TEN and TEM were estimated to be a lowly heritable traits. Heritability estimates from dam components were higher than those from sire components. These differences might be due to non-additive genetic effect and maternal effect. 3. The estimates of heritabilities and standard errors derived from combined variance components for different degrees of backcross were $0.47\pm0.11$ (BCO), $0.42\pm0.16$ (BC1), $0.51\pm0.29$ (BC2) for TEN, $0.59\pm0.20$ (BCO), $0.43\pm0.17$ (BC1), $0.35\pm0.18$ (BC2) for AEW, $0.28\pm0.12$(BC0), $0.20\pm0.11$(BC1), $0.18\pm0.14$ (BC2) for TEM. Heritability estimates for AEW and TEM were decreased by backcrossing while those for SM and TEN remained constant. Since backcrossing contributes to increased homozygosity, the genetic variation of the traits (AEW and TEM) decreased . 4. The pooled estimates of genetic correlation coefficients were -0.55 between SM and TEN, 0.20 between SM and AEW, -0.29 between TEN and AEW, 0.82 between TEM and TEN, 0.31 between TEM and AEW, -0.42 between TEM and SM. The genetic correlation between TEM and TEN was higher than that between TEM and AEW, and it was suggested that egg mass was strongly affected by egg number. Also, age at sexual maturity(SM) contributes to egg mass(TEM). 5. When backcrossing was carried out successively, the genetic correlation between TEM and TEN increased (BC0：0.79, BC1：0.82, BC2：0.91) but those between TEM and SM decreased (BC0：-0.54, BC1：-0.36, BC2：-0.09) with successive backcrosses.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.457-464
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• 2008

Heritability and genetic correlation for reproductive traits in Yorkshire pig breed were estimated using Bayesian method via Gibbs sampling. The data set consisted of 9,609 reproductive records at pig breeding farm in Korea. For estimating those parameters using Gibbs sampling, 5,000 cycles of ‘burn-in’ period were discarded among a total of 55,000 samples. Out of the remaining 50,000 samples, 5,000 estimates by each parameter were retained and used for analyses to avoid any correlation among adjacent samples. The reproductive trait considered in this study were total number of born piglets(TNB) and estimated by two different models. The estimated heritability and permanent environmental effect using Gibbs sampler were 0.12±0.020 and 10.9±1.63, respectively. Estimated genetic correlations considered parities as different traits were distributed from 0.99 to －0.13. Such results indicated that reproductive traits for sows should be considered as different traits.

• Journal of agriculture & life science
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• v.44 no.5
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• pp.55-64
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• 2010

This study was conducted to estimate genetic parameters for reproductive traits using multivariate animal models in Yorkshire breed. For the study, 4,989 records for litter traits collected between the year 2001 and 2005 from Yorkshire pigs in K GGP were used. The effects of environmental factors such as farrowing year, parity, weaning to estrus interval (WEI), and suckling period were statistically significant (p<0.05), but farrowing season was not significant, for reproductive traits. The estimates genetic correlations and phenotypic correlations in total number of born and number of suckling, was shown to highly correlated. The genetic correlations were higher than phenotypic correlation. The estimates of heritabilities for reproductive traits, considering permanent environment effects (PE) were much lower than those obtained when permanent environment effects were not considered (NPE) in the model. The estimates of heritabilities were 0.240 and 0.076 for total number of born and 0.187 and 0.096 for number of suckling in NPE, and PE, respectively. These results itivcate that PE should be considered in the statistical mode to estimate more acco ate breeding values.

• 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.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.117-117
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• 2003

다시마(Laminaria japonica) 생태육종 연구의 일환으로 완도산과 백령도산 품종의 재배시험을 전남 고흥군 명천어장과 계도어장에서 2001년부터 2002년까지 실시하였다. 시험기간 중 어장의 수온, 염분농도, 유속, 용존산소농도는 구간별로 유의차가 없었으며 수온은 1월부터 7월까지 점차 상승하였고, 염분농도는 5월까지 상승하다가 6월과 7월에 낮아졌다. 유속은 저층에서보다 표층에서 빨랐고, 용존산소농도는 1월부터 7월까지 점차적으로 낮아졌다. 어장의 영양염 변화는 구간별로 1월부터 7월까지 유의차가 없었으며 암모니아염이 5월에 다소 증가하였다. 일반적으로 전장과 엽폭은 4월까지 증가하다가 끝녹음으로 인하여 4월이후에는 다소 감소하였으나, 엽두께, 전중량, 비대도는 7월까지 계속적으로 증가하였다. 형질간의 상관관계는 모두 1%와 5% 수준에서 유의차가 있었다. 각형질에 있어서 품종과 환경간에 월별로 질적교호작용과 양적교호작용중 어느 한 쪽이 나타났다. 품종시험에 의한 유전력은 엽폭에서 가장 높았고, 엽두께에서 가장 낮았다. 표현형상관, 유전상관, 환경상관계수는 형질간에 대부분 높은 값을 보였으나 엽두께와 전중량간의 값이 일반적으로 낮았다. 부모와 자식간의 회귀에 의한 유전력은 계도어장의 엽두께에서 가장 높았으나 일반적으로 전중량에서 높았고, 육종가와 유전상관은 전중량에서 가장 높았다. 각 형질의 상대적 경제 가치를 고려한 선발 총점은 명천어장에서의 완도산 품종에서 가장 높았다.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 2001.05a
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• pp.35-43
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• 2001

일대잡종육종이란 현대의 다양한 육종기술 중 하나로 교배 제1세대의 잡종강세현상을 곧바로 이용하는 것으로 여러 작물에서 실용적으로 이용되고 있다. F$_1$잡종종자를 생산하려면 자가수분을 통제해야 하는데 웅성불임을 이용하면 자친의 화분제거 노력이 생력되어 경제적인 종자생산이 가능하다. 연초는 자식성 작물로 잡종강세는 높지 않으나 종간 교잡에 의한 cms가 만들어진 이후 버어리종 등에서는 60년대부터 직적형질에 가깝게 유전되는 우성 단일유전자의 지배를 받는 N. logniflora의 역병(race 0)저항성을 도입한 웅성불임(cms) F$_1$잡종이 활발하게 이용되어 왔다. 최근에는 cms F$_1$잡종의 이용영역이 넓어져 우리나라의 경우 N. glutinosa에서 유래한 우성 단일인자 TMV저항성을 도입한 황색종 cms F$_1$잡종 KF 114가 주 재배품종이 되었고 버어리종에서는 VAM에서 유래한 열성단일유전자의 지배를 받는 PVY저항성이 도입된 KB 111의 확대재배가 예상되고 있다. 본 글에서는 cms F$_1$잡종의 국내외 이용 사례를 살펴보고 cms F$_1$잡종의 육성과 이용방향, cms F$_1$잡종 종자생산에 관하여 기술하였다. 그리고 병저항성뿐 아니라 알칼로이드함량, 염록소함량, DVT나 챤-abienol 및 SE함량 등 질적형질에 가깝게 유전되고 유전양식이 명확하게 밝혀진 화학성분에 대해서도 F$_1$잡종 육성의 대상 형질로 논의하였다.

• Journal of Life Science
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• v.8 no.4
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• pp.431-436
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• 1998

These studies were carried out to obtain useful information about the effective selection of vegetable perilla by estimating the genetic relationships between the heritabilities and the genetic correlations of quantitative traits among eight agronomic characters from 91 perilla varieties. The positive correlations were showed among characters such as between leaf weight and leaf size, leaf weight and leaf length, leaf weight and leaf width, leaf weight and plant height, leaf weight and stem diameter, leaf size and leaf length, leaf size and leaf width, leaf size and plant height, leaf size and stem diameter , leaf length and leaf width, leaf length and plant height, leaf length and stem diameter, leaf width and plant height, leaf width and stem diameter, plant height and stem diameter, plant height and the number of internodes per plant, and the number of internodes per plant and the number of leaves per plant. Heritabilities were high as from 0.7311 to 0.9112 among leaf weight, leaf size, leaf length, leaf width, plant height, stem diameter, and the number of internodes per plant.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.7-14
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• 1987

Extensive studies were undertaken to analyze the genetic basis of economically important quantitative characters in the silkworm by diallel crosses of four inbred lines differing widely in silk yielding ability. Some differences between the reciprocal corsses were detected in cocoon weight, cocoon shell weight, cocoon filament length and cocoon filament weight in case the parental lines were greatly differenent each other in silk yielding ability. The general combining ability (GCA) varied with the inbred lines and M242, a Chieese sexlimited larval marking variety showed high GCA value in the economic characters, such as cocoon yield, cocoon weight, cocoon filament length and weight, and raw silk percentage. The highest heterosis effect, about 13% to 14% was seen in cocoon and raw silk yield and it was low in cocoon reelability and raw silk percentage with less than 1%. It is advisable to improve highly heritable quantitative characters such as larval duration, cocoon shell weight, cocoon filament length and raw silk percentage by means of selection, and to select single crosses with high heterosis effect for cocoon weight and cocoon yield which show overdominance. Genetic correlation should be considered when more than two characters are targets for improvement and selecting high cocoon shell weight is effective to breed high silk yielding varieties. It is difficult to improve cocoon reelability because of low heritability (0.11) and its negative correlation with cocoon-silk quality.

• Journal of Animal Science and Technology
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• v.49 no.4
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• pp.437-442
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• 2007

The melanocortin-4 receptor(MC4R) is virtually expressed in all brain regions and plays an important role in energy homeostasis in mammals. MC4R has been intensively studied as a trait gene controlling economically important traits, such as growth and feed conversion, etc. Six hundreds and sixty Duroc pigs were genotyped for the MC4R locus and analyzed their relationships with breeding values for average daily gain(ADG), backfat thickness(BF), days to 90kg(D90) and feed conversion(FC). The estimated genotype frequencies for the all Duroc pigs were: 30.8%, 45.2%, 24.1% for AA, AB and BB genotypes, respectively. The mutant A allele was significantly associated with ADG, D90 and BF whereas no significant relationship was found with FC. The change of gene frequencies by generation was shown in both selected and culled groups. These results indicate that the MC4R polymorphism could be integrated in the present selection program to realize a marker-assisted selection for the growth traits of the Duroc population.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.263-267
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• 2011

Genomic fingerprinting methods are useful in determining relatedness among bacterial strains. However, random coincidences in sizes of two DNA fragments in two different fingerprints may occur, resulting in erroneous interpretation of relatedness between two bacterial genomes. In this study, I estimated the probability of occurrence of DNA bands of identical size in fingerprints of two unrelated genomes, so that the significance of fingerprint-based estimation of genome relatedness could be analyzed. The probability could be estimated as outputs of a function formulated with the three parameters: the numbers of observed fragments, all possible sizes of fragments and observed fragments common in a given pair of fingerprints. The parameter most instrumental to significance of relatedness estimation was the number of all possible sizes of fragments. To keep the number of coincidentally-common size of fragments below 10, about 200 fragments should be distinguishable in the fingerprints.