scholarly journals Using genealogy to improve selection efficiency of pedigree method

2008 ◽  
Vol 65 (1) ◽  
pp. 25-30 ◽  
Author(s):  
José Airton Rodrigues Nunes ◽  
Alexsander Luís Moreto ◽  
Magno Antonio Patto Ramalho
Keyword(s):  
Selection Efficiency ◽  
Yield Data ◽  
Linear Unbiased Prediction ◽  
Lattice Design ◽  
Simple Lattice ◽  
Best Linear Unbiased ◽  
The Common ◽  
The Mean ◽  
Selection For ◽  
Opposite Extreme

In the pedigree method of conducting an autogamous population of segregating plants, the genealogy of the progenies is registered. Although labor-intensive, these data are rarely used. One possibility of exploiting this information is to improve selection efficiency using BLUP (Best Linear Unbiased Prediction). In this study BLUP with genealogy inclusion was compared to the mean in the progenies evaluation conducted by the pedigree method. Progenies of crosses of the common bean lines BRS MG Talismã and BRS Valente in F4:6 and F4:7 were used. The 256 F4:6 progenies were sown in February 2005, in southeast of Brazil, in a 16 <FONT FACE=Symbol>´</FONT> 16 simple lattice design. The grain yield data were subjected to BLUP analysis with inclusion of genealogy. Based on this analysis and the mean, the 30 progenies with best and worst performance were selected. These 60 F4:7 progenies were classified in relation to the origin, i.e., selected by BLUP, mean, or BLUP and mean and coincident results were obtained. In the selection for best performance, the efficiency of BLUP was 2.4% higher than the mean. In the selection for the opposite extreme, BLUP analysis was however not advantageous. The progenies <FONT FACE=Symbol>´</FONT> environments interaction indicates the need for an evaluation of the progenies in different environments before beginning selection.

Selection on lean growth in a nucleus of Landrace pigs: an analysis using Gibbs sampling

1996 ◽  
Vol 63 (2) ◽  
pp. 243-253 ◽  
Author(s):  
M. C. Rodriguez ◽  
M. Toro ◽  
L. Silió
Keyword(s):  
Gibbs Sampling ◽  
Variance Components ◽  
Fixed Effects ◽  
Prediction Method ◽  
Environmental Parameters ◽  
Linear Unbiased Prediction ◽  
Normal Distributions ◽  
Lean Growth ◽  
Best Linear Unbiased ◽  
Selection For

AbstractData from 4150 Landrace pigs tested during the period 1989-94 for backfat thickness and age at 100 kg in an open selection nucleus were analysed with the standard restricted maximum likelihood/best linear unbiased prediction method and with a Bayesian approach based on the marginal posterior distributions of parameters of interest achieved via Gibbs sampling. Breeding values and fixed effects were sampled from normal distributions and (co)variance components from inverted Wishart distributions. The Bayesian analysis indicated that the selection was effective for both traits. Assuming flat priors for the (co)variance components, the posterior means of the annual rates of response to selection for both traits were −0·473 days and −0·212 mm. The influence of informative priors constructed from (co)variances estimated in the French Landrace breed on inferences about genetic and common environmental parameters, genetic group effects and total and annual responses was also examined.

scholarly journals Genetic evaluation and selection correlated response of growth traits in Japanese quail

2020 ◽  
Vol 50 (2) ◽  
pp. 325-333
Author(s):  
M.M. El-Attrouny ◽  
E.A. Manaa ◽  
S.I. Ramadan
Keyword(s):  
Growth Traits ◽  
Best Linear Unbiased Prediction ◽  
Correlated Response ◽  
Genetic Trend ◽  
Linear Unbiased Prediction ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Best Linear Unbiased ◽  
Selection For ◽  
Genetic Trends

Objectives of the current study were to i) investigate effects of selection for bodyweight at four weeks old on bodyweight (BW) and bodyweight gain (BWG) across four generations; ii) estimate correlated response to selection for BW and BWG at different ages; and iii) document best linear unbiased prediction (BLUP) of genetic trends for BW and BWG across four generations of selection. A total of 3540 chicks from 444 sires and 885 dams were used to estimate heritabilities, and genetic and phenotypic correlations for growth traits, including BW at 0, 2, 4, and 6 weeks, and BWG between 0 and 2, 2 and 4, 4 and 6, and 0 and 6 weeks. The selection effects, correlated responses and genetic trend for BW and BWG across generations were quantified by applying the animal model. Estimates of heritability for BW and BWG ranged from 0.22 to 0.42 and from 0.18 to 0.23, respectively. Ranges of genetic and phenotypic correlations for BW varied from 0.31 to 0.92 and 0.05 to 0.65, respectively. Moreover, estimates of genetic and phenotypic correlations for BWG at different ages were from 0.12 to 0.72 and 0.17 to 0.60, respectively. Bodyweight and BWG estimates after four generations of selection were significantly higher than those of the base generation. Moreover, contrasts of generation means were significant across the four generations. The genetic trends across the generations clarified that BLUP estimates for BW and BWG gradually increased with the advance of generations until the fourth generation. Keywords: best linear unbiased prediction, bodyweight, heritability, selection, genetic trend

A comparison of alternative nucleus breeding systems and a sire referencing scheme for sheep improvement

1996 ◽  
Vol 62 (2) ◽  
pp. 265-270 ◽  
Author(s):  
J. A. Roden
Keyword(s):  
Selection Response ◽  
Best Linear Unbiased Prediction ◽  
Breeding Systems ◽  
Linear Unbiased Prediction ◽  
Sequential Selection ◽  
Best Linear Unbiased ◽  
The Mean ◽  
Nucleus Breeding ◽  
Open Nucleus ◽  
Selection Of

AbstractStochastic simulation was used to compare selection response and rate of inbreeding in four nucleus breeding systems and a sire referencing scheme for sheep: an open nucleus system (ONS), an open nucleus system with sequential selection of the nucleus (ONS-S), a sire referencing scheme (SRS) and a dispersed open nucleus system (DONS). Selection was based on best linear unbiased prediction of breeding values for a single trait measurable on all individuals prior to selection. Selection in a population of 1200 ewes equally divided into 10 flocks was simulated over a 15-year period. The mean rate of genetic gain was proportionately about 0-15 higher in ONS-S and DONS compared with ONS and SRS. The rate of inbreeding in SRS was considerably lower and in ONS-S, considerably higher, than in the other systems. The level of prolificacy in the population did not influence the relative ranking of the breeding systems but may have implications for their optimal structure.

scholarly journals Simultaneous prediction in the generalized linear model

2018 ◽  
Vol 16 (1) ◽  
pp. 1037-1047
Author(s):  
Chao Bai ◽  
Haiqi Li
Keyword(s):  
Linear Model ◽  
Generalized Linear Model ◽  
Target Function ◽  
Finite Sample ◽  
Linear Unbiased Prediction ◽  
Composite Target ◽  
Mean Values ◽  
Simultaneous Prediction ◽  
Best Linear Unbiased ◽  
The Mean

AbstractThis paper studies the prediction based on a composite target function that allows to simultaneously predict the actual and the mean values of the unobserved regressand in the generalized linear model. The best linear unbiased prediction (BLUP) of the target function is derived. Studies show that our BLUP has better properties than some other predictions. Simulations confirm its better finite sample performance.

Genetic changes in Canadian performance-tested pigs for fat depth and growth rate

1996 ◽  
Vol 76 (1) ◽  
pp. 41-48 ◽  
Author(s):  
B. W. Kennedy ◽  
V. M. Quinton ◽  
C. Smith
Keyword(s):  
Growth Rate ◽  
Performance Testing ◽  
Economic Benefits ◽  
Breeding Value ◽  
Improvement Program ◽  
Linear Unbiased Prediction ◽  
Genetic Changes ◽  
Best Linear Unbiased ◽  
The Mean ◽  
Genetic Trends

Data on more than 1.3 million pigs of four breeds in four regions of Canada were used to estimate genetic changes in fat depth and growth rate from 1976 to 1993. Analysis was by a multi (two)-trait best linear unbiased prediction (BLUP) animal model within breed and across regions. The genetic changes were measured as the changes in average estimated breeding value (EBV) over years.The across-breed average total phenotypic changes from 1976 to 1993 were− 3.9 mm in fat depth (26% of the mean) and− 17 d in age at 100 kg (9% of the mean). The multi-trait BLUP estimates of the genetic trends were similar to single-trait BLUP estimates. The mean EBV and the changes were similar for the four regions. The changes were larger in the Landrace and Yorkshire breeds than in the Duroc and Hampshire. The overall genetic trends were − 1.44% of the mean yr−1 in fat depth and − 0.36% of the mean yr−1 in age at 100 kg. The trend for age at 100 kg increased over time as better methods of deriving the EBV were implemented. The current rates of pig improvement in Canada are good and yield large economic benefits. However, they could be improved to recoup the full gains possible through the Canadian Swine Improvement Program. Key words: Canadian pigs, performance testing, genetic trends

scholarly journals GENETIC PARAMETERS OF GIROLANDO CROSSBRED COWS IN DAIRY HERDS IN THE STATE OF ACRE, BRAZIL

2020 ◽  
Vol 23 (1cont) ◽  
Author(s):  
Andressa Pereira Braga ◽  
José Marques Carneiro Júnior ◽  
Antônia Kaylyanne Pinheiro ◽  
Maurício Santos Silva
Keyword(s):  
Maximum Likelihood ◽  
Milk Production ◽  
Genetic Parameters ◽  
Heritability Estimate ◽  
Restricted Maximum Likelihood ◽  
Dairy Herds ◽  
Genetic Progress ◽  
Linear Unbiased Prediction ◽  
Best Linear Unbiased ◽  
Selection For

This study aimed at estimating genetic parameters for milk production and conformation characteristics in Girolando crossbred dairy cows reared in the High and Low Acre region using the restricted maximum likelihood methodology, under an animal model. We estimated the variance components and genetic parameters using the REML/BLUP procedure (Restricted Maximum Likelihood Methodology/Best Linear Unbiased Prediction). The estimated average for milk production for 305 days of lactation (P305) was of 1523.25 ± 481.11 kg, with a heritability of 0.38 for this characteristic. The conformation characteristics showed no significant correlation with milk production. The phenotypical correlations between the linear characteristics of type were, in general, positive and moderate. The P305 obtained in this study can be considered low and indicates that there is a possibility of increasing milk production through selection in herds along with the use of tested and proven bulls. The heritability estimate found (0.38) indicates that there is genetic variability for milk production, demonstrating that selection for this characteristic would result in genetic progress.

The Accuracy of Marker-Assisted Selection for Quantitative Traits Within Populations in Linkage Equilibrium

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1367-1372 ◽  
Author(s):  
Louis Ollivier
Keyword(s):  
Quantitative Traits ◽  
Infinite Family ◽  
Best Linear Unbiased Prediction ◽  
Linkage Equilibrium ◽  
Linear Unbiased Prediction ◽  
Selection Scheme ◽  
Sib Families ◽  
Best Linear Unbiased ◽  
Selection For ◽  
Combined Selection

Abstract Using the concept of conditional coancestry, given observed markers, an explicit expression of the accuracy of marker-based selection is derived in situations of linkage equilibrium between markers and quantitative trait loci (QTL), for the general case of full-sib families nested within half-sib families. Such a selection scheme is rather inaccurate for moderate values of family sizes and QTL variance, and the accuracies predicted for linkage disequilibrium can never be reached. The result is used to predict the accuracy of marker-assisted combined selection (MACS) and is shown to agree with previous MACS results obtained by simulation of a best linear unbiased prediction animal model. Low gains in accuracy are generally to be expected compared to standard combined selection. The maximum gain, assuming infinite family size and all QTLs marked, is about 50%.

scholarly journals Genetic Variation of Some Tobacco (Nicotiana Tabacum L.) Genotypes by Morphological Traits

2019 ◽  
Vol 50 (1) ◽  
pp. 1-7
Author(s):  
Z. Porkabiri ◽  
N. Sabaghnia ◽  
R. Ranjbar ◽  
H.H. Maleki
Keyword(s):  
Leaf Area ◽  
Leaf Length ◽  
Leaf Width ◽  
Lattice Design ◽  
Simple Lattice ◽  
Nicotiana Tabacum L ◽  
Leaf Yield ◽  
Effective Selection ◽  
Selection For ◽  
Ideal Genotype

Abstract Simple lattice design with two replicates was used to evaluate 25 tobacco genotypes. The following eight traits were measured and evaluated: plant height (PH), leaf length (LL), leaf width (LW), leaf number per plant (LN), stem girth (SG), leaf area (LA), dry leaf yield (DLW), and fresh leaf yield (FLW). The genotype by trait biplot for tobacco dataset explained 73% of the total variation of the standardized data. The polygon view of genotype by trait presented for the eight different traits of tobacco genotypes showed six vertex cultivars (G4, G5, G11, G12, G18, and G21). Genotype G21 had the highest values for most of the measured traits. Based on a vector view biplot, strong positive associations among LL, DLW, FLW, and LA were detected while near zero correlations between LL and SG, as well as between LL and PH were observed. Generally, based on ideal genotype and ideal tester biplots, it was demonstrated that the selection for high leaf yield should be performed via leaf length, leaf width, and leaf area traits identified as effective selection criteria for high yielding cultivars.

scholarly journals Early selection and classification of yerba mate progênies

2018 ◽  
Vol 53 (3) ◽  
pp. 279-286
Author(s):  
Ivar Wendling ◽  
José Alfredo Sturion ◽  
Carlos André Stuepp ◽  
Cristiane Aparecida Fioravante Reis ◽  
Magno Antonio Patto Ramalho ◽  
...  
Keyword(s):  
Mass Production ◽  
Mixed Model ◽  
Early Selection ◽  
Ilex Paraguariensis ◽  
Yerba Mate ◽  
Linear Unbiased Prediction ◽  
Best Linear Unbiased ◽  
Selection For ◽  
Selection Of

Abstract: The objective of this work was to evaluate the feasibility of early selection of open-pollinated yerba mate (Ilex paraguariensis) progenies, and to classify the best parents and candidates for clones. The germplasm is composed of 140 progenies collected from areas within the natural distribution of the species in Southern Brazil and a commercial genotype (control). The experiment was established in Ivaí, in the state of Paraná, Brazil, in March 1997, in randomized complete blocks, with ten replicates, and linear plots of six plants. The commercial mass (kg per plant) of leaves and branches smaller than 7 mm was harvested at 2.5, 4.5, 6.5, and 18.7 years of age. The statistical evaluation was performed using the mixed model procedure with restricted maximum likelihood/best linear unbiased prediction, using the Selegen software. High selective accuracy, significant progeny effects, and genetic variability for commercial mass production were observed for the four harvesting ages. The application of early selection for leaf mass production is feasible for yerba mate progenies harvested at 6.5 years. The selection of the best trees, either for use as parents or as candidates for cloning, provides significant gains for the genetic breeding of yerba mate.

Effects of nonrandom mating schemes to delay the inbreeding accumulation in cultured populations of coho salmon (Oncorhynchus kisutch)

2004 ◽  
Vol 61 (4) ◽  
pp. 547-553 ◽  
Author(s):  
José A Gallardo ◽  
Jean Paul Lhorente ◽  
Ximena García ◽  
Roberto Neira
Keyword(s):  
Coho Salmon ◽  
Random Mating ◽  
Oncorhynchus Kisutch ◽  
Linear Unbiased Prediction ◽  
Breeding Values ◽  
Nonrandom Mating ◽  
The Family ◽  
Best Linear Unbiased ◽  
The Mean ◽  
High Degree

Chilean salmon culture is based on a high degree of artificial selection, which has had the tendency to increase the inbreeding (F). Three types of nonrandom mating were evaluated to control the inbreeding in two best linear unbiased prediction selected coho salmon (Oncorhynchus kisutch) populations (even and odd). These included compensatory mating on the basis of breeding values (C), modified compensatory mating (C1) based on the family mean of breeding values, and mating that minimized the mean co-ancestry of the group selected (MC scheme). In the odd population, the MC scheme (F = 2.0%) reduced the increase in inbreeding of the next generation by 50% and 46% when compared with random mating of selected individuals with sib mating restricted (F = 3.9%) and with C (F = 3.7%), respectively. In the even population, the MC scheme reduced the increase in inbreeding by 14% compared with C1 (9.7 versus 11.2). In both populations, the MC scheme also reduced variance in inbreeding (even, 59%; odd, 39%). Thus, the MC scheme was more efficient in reducing the increase and variance of inbreeding, thus limiting the expression of inbreeding depression. Although the MC scheme was more time consuming, we recommend this scheme to carry out crosses in each generation.

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