• Journal of Sericultural and Entomological Science
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• v.28 no.2
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• pp.21-27
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• 1986

Since the estimate of the genetic relations between characters gave us effective basic informations about the selection of good strains of silkworm, the experiment was carried out to estimate the heritability and the genotypic correlation, etc. using the 21 combinations F1, 's by diallel crosses of seven strains of the silkworm. As the result of this experiment some conclusions obtained were as follows ; 1. The genotypic correlation is estimated highly positive in the heritability for all the 9 characters. 2. The correlations between all the characters are positive and the genotypic correlation is generally higher than the phenotypic one. 3. Since all the correlations between the have length and other characters are highly positive, it can be considered that the effects of the other characters on the have length are very important.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.9-14
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• 2012

The purpose of this study was to estimate heritabilities and genetic correlations for reproductive and productive traits and to apply their estimates to selection strategies in a swine population. Reproductive and productive traits considered in this study were number of born alive piglet (NBA), number of weaned piglet (NW), loin eye area (LEA), days to 90 kg (D90KG), back fat thickness (BF), and lean meat content (LEAN). Data were collected from 9,886 litters on 2,447 sows for reproductive traits and 10,181 gilts and boars for productive traits from Jan. 2000 to Dec. 2008 in a swine GGP farm. The statistical model to estimate genetic parameters for considering traits was a multiple traits animal model with including animal and maternal additive effects and litter effects on reproductive traits and animal additive effects on productive traits as random as well as some of fixed effects. For estimating (co) variance components of several random effects, restricted maximum likelihood methodology was used on this assumed model. The estimated heritabilities by animal additive effects and maternal effects were 0.07 and 0.02 for NBA and 0.03 and 0.02 for NW, respectively. Genetic correlation estimate for direct genetic effects between NBA and NW was 0.14. Heritability estimates for direct genetic effects were 0.19, 0.39, 0.36, and 0.43 for LEA, D90KG, BF and LEAN, respectively. The genetic correlation of LEA with LEAN was 0.35. Productive traits were antagonistically correlated with reproductive traits. From these results it is concluded that, if selection is done for strong positive effects of reproductive traits, then this would decline productive performance.

• Korean Journal of Microbiology
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• v.33 no.3
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• pp.203-209
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• 1997

형질전환은 가장 먼저 연구된 유전물질 전이 기작으로(3,29,36), 자연적 형질 전환과 인위적 형질 전환으로 구별할 수 있다. 자연적 형질 전환은 세균에게서만 일어나며, 이때 수여체 세균은 적정 조건, 즉, 형질 전환 능력이 있는 생리적 상태(competene)가 되면 능동적으로 세포의 DNA를 받아들여 그들 유전 정보에 합치게 된다. 하지만 재조합 DNA 기술이 발달된 이후로 인위적 형질 전환이 원핵세포와 진핵세포에서 사용되었다(48). 자연적 형질 전환은 DNase와의 반응이 민감하다는 점에서 접합과 형질 도입과 구별된다. 형질 전화에 의한 유전자 전이가 세포으 DNA에 의해서 일어나는 한 DNase가 공격할 수 있고, DNA는 분해되어 형질 전환이 방해될 수 있다. 하지만, 형질 도입되는 DNA는 파지의 단백질막(capsid)에 보호되어 세포외로 절대 노출되지 않아 DNase에 의해서 영향을 받지 않고, 접합에서도 DNA는 세포와 세포의 접촉에 의해서 전이되어 공여체에서 수여체로 DNA가 전이될 때 역시 DNase에 노출되지 않고 일어날 수 있다.

• Journal of Animal Science and Technology
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• v.54 no.4
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• pp.275-282
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• 2012

The data including milk yields, fat and protein percent for 628,395 heads collected by National Agricultural Cooperative Federation, 15 type traits and final score for 62,262 heads collected by Korea Animal Improvement Association, which were born in 1998 to 2004, and net profits calculated from milk price and raising expenses of individuals were used to estimate genetic parameters. The highest positive genetic correlation, 0.81, was shown between body depth (BD) and loin strength (SR). Genetic correlations between body depth (BD) and udder depth (UD), front teat placement (TP) and front teat length (TL) were -0.23, which were lowest among the linear type traits. Furthermore, medium level of negative genetic correlations were shown the milk yield with milk contents rate traits. Mostly low level of positive genetic correlations were shown between the milk traits and linear score traits except milk yield and stature. Most of the genetic correlations of between the linear score traits and net profit were low level of positive or negative genetic correlations. Among the genetic correlations, body depth (BD), angularity (DF) and rear attachment width (UW), and final score (FS) with net profit were high as 0.17, 0.17, 0.18 and 0.18, respectively. Finally all of the genetic correlations between net profit and milk traits were positive and higher than the linear traits with positive genetic correlations. The results of this study suggest that net profit has been related with the linear traits, such as body depth (BD), angularity (DF) and rear attachment width (UW) traits, and furthermore, milk traits including yield and contents rates influence positively and greatly on net profit.

• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.255-268
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• 1990

This study was carried out to investigate the time-trends of genetic parameters of the dosed flock population which selected for improving egg production. Data for two layer pure lines, Line-W (Single Comb White Leghorn) and Line-B (brown layer) which have been maintained at the Mani Breeding Farm were collected from 1980 to 1985 during 5 generations. The effective number of parents per generation ranged from 148 to 366 in Line-W and 85 to 355 in Line-B, and the cumulative expected inbreeding coefficients during 5 generations of selection were 15％ and 1.6％. So inbreeding could not be considered a critical factor on estimating the genetic parameters, heritabilities and genetic correlations Heritabilities of EN 300 and EN 400, primary two selected traits were significantly decreased during 5 generations but the estimates of the other 03its not showed the consistent decreasing pattern significantly. No time trends of probable consequence were evident in the genetic correlation coefficients of the traits studied. The reason for that situation was attributed to the fact that selection was conducted for multiple objectives and the relative importance of selection for the studied traits were not consistent by generations.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.613-620
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• 2008

The genetic parameters used in National Hanwoo Genetic Evaluation(NHGE) were needed to be monitored and updated periodically for accounting any possible changes in population parameters due to selection and environmental changes. Genetic parameters were estimated with single and two-trait models with MTDFREML package using 2,791 carcass records of steers collected from Hanwoo Progeny Test Program(HPTP). Single and two-trait models gave similar parameter estimates for all traits. The heritability estimates from single and two-trait models for carcass weight(CW), dressing percentage(DP), eye muscle area(EMA), back fat thickness(BFT) and marbling score(MS) were 0.30, 0.30, 0.37, 0.44 and 0.44, respectively. The heritability estimates for all the traits except BFT were slightly lower than those used in NHGE but seemed to be within the acceptable ranges. However, further monitoring is needed because the data might not have fully reflected the changes such as carcass grading standards in performance testing program. In order to shift statistical model of NHGE from single trait model to multiple-trait model, the genetic correlations between carcass traits were estimated with pairwise two-trait models. The genetic correlation coefficients between CW and DP, between CW and EMA, between CW and BFT and between CW and MS were 0.44, 0.63, 0.17 and 0.06, respectively. Those between DP and EMA, between DP and BFT and between DP and MS were 0.29, 0.40 and 0.20. Those between EMA and BFT and between EMA and MS were －0.24 and 0.15, respectively. The genetic correlation coefficient between BFT and MS was 0.03.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.360-369
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• 1988

This experiment was carried out to investigate the heritabilities, genetic correlations, path-coefficients, selection indexes and genetic advances for the desirable characteristics of naked-barley (Hordeum vulgare L.) in the central region of Korea. Genetic advances were calculated from selection indexes for each characters. It was considered that selection efficiency was increased in case it was calculated from the combination of two or three characters. These characters should be very useful agronomic characters for selection because they could be measured and counted easily, and thus it is also possible to save labour and expenses.

• Journal of Animal Science and Technology
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• v.46 no.2
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• pp.145-154
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• 2004

This study was conducted to estimate genetic parameter of Duroc, Landrace and Yorkshire breeds based on the on-farm performance tested records of 57,316 pigs under the supervision of Korean Animal Improvement Association from 1992 to 1999. Genetic parameters were estimated with a multiple trait animal model by using DF - REML. The result obtained in this study was summarized as follow ; The estimated heritabilities of Duroc, Landrace and Yorkshire were 0.46${\sim}$0.65 for the average backfat thickness, 0.28${\sim}$0.31 for loin depth, 0.50～0.60 for percent lean, 0.45${\sim}$0.55 for the average daily gain, 0.38${\sim}$0.50 for age at 90kg, respectively. Phenotypic correlation of average backfat thickness with loin depth, percent lean, average daily gain and age at 90㎏ for the three breeds were -0.12${\sim}$-0.01, -0.81${\sim}$-0.76, 0.34${\sim}$0.46, and -0.41${\sim}$-0.33, respectively. Phenotypic correlation of loin depth with percent lean, average daily gain and age at 90kg were 0.12${\sim}$0.23, 0.03${\sim}$0.21, and -0.17${\sim}$-0.03, respectively. Phenotypic correlation of percent lean with average daily gain and age at 90kg were -0.37${\sim}$-0.26 and 0.26～0.35, respectively. Phenotypic correlation of average daily gain with age at 90kg was -0.97${\sim}$-0.95. The estimated genetic correlation coefficients of average backfat thickness with loin depth, percent lean, average daily gain and age at 90kg estimated for the three breeds were -0.17${\sim}$0.03, -0.79${\sim}$-0.69, 0.24${\sim}$0.45 and -0.41${\sim}$-0.19, respectively. The estimated genetic correlation coefficients of loin depth with percent lean, average daily gain and age at 90kg were 0.11～0.19, 0.23 and -0.30～-0.20, respectively. The estimated correlation coefficients of percent lean with average daily gain and age at 90kg were -0.36${\sim}$-0.13 and 0.10～0.34, respectively. The estimated genetic correlation coefficients of average daily gain with age at 90㎏ was -0.96${\sim}$-0.95.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.2
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• pp.174-179
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• 1985

Estimate of heritabilities, genotypic and phenotypic correlations and path coefficient analysis were performed for the seven characters of barley cultivars (Hordeum vulgare L.). Heritabilities of broad sense for stem length and spike length were 0.923 and 0.907. Kernels per spike, grain yield and 100 grain weight also showed high heritabilities. High genotypic and phenotypic correlations existed between stem length and 100 grain weight. Grain yield showed highly significant phenotypic correlation with spike length, 100 grain weight and kernels per spike. Genotypic correlations between those characters were moderately high. Number of stem had greatest direct effect but the number of spike had a strong negative direct effect upon grain yield. Kernels per spike via number of spike showed greatest indirect effect and the number of stem via number of spike showed strong negative indirect effect upon grain yield.

• 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.