The use of 'bending' in multiple trait selection of Border Leicester - Merino synthetic populations

1986 ◽  
Vol 37 (5) ◽  
pp. 539 ◽  
Author(s):  
B Gunawan ◽  
JW James
Keyword(s):  
Body Weight ◽  
Genetic Parameters ◽  
Genetic Selection ◽  
Positive Definite ◽  
Multiple Trait ◽  
Genetic Covariance ◽  
Synthetic Populations ◽  
Selection Indices ◽  
Genetic Covariances ◽  
Selection Of

The consistency of phenotypic and genetic parameters estimated for various body weight and wool characters in Border Leicester-Merino synthetic populations was investigated by calculating the eigenvalues of matrices of phenotypic covariances (P), genetic covariances (G), and the product of the inverse of the phenotypic with the genetic covariance matrix (P-1G). If these estimates were found to be inconsistent (non-positive definite), the bending technique was applied before genetic selection indices were calculated. In general, the P were positive definite, but the G or P-1G were always non-positive definite. The results suggest that P and G should always be checked carefully before genetic selection indices are calculated. The bending technique was quite effective in giving reasonable results for accuracy of selection.

scholarly journals Estimation of Genetic Parameters for Body Weight and Some Colour Traits in the Seventh-generation Index Selected Nigeria Heavy Local Chicken Ecotype

2021 ◽  
Author(s):  
I.J. Ohagenyi ◽  
F.C. Iregbu ◽  
V.C. Udeh
Keyword(s):  
Body Weight ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
The Body ◽  
Pedigree Selection ◽  
Egg Colour ◽  
Local Chicken ◽  
Range Test ◽  
Estimation Of Genetic Parameters ◽  
Selection Of

Background: This study was conducted to estimate the genetic parameters of body weight and some colour traits in seventh generation (G7) index selected Nigerian Heavy Local Chicken Ecotype (NHLCE) progenies at point of lay to 12 weeks. Methods: 5 sires and 12 hens were used to generate the progenies used for the experiment. Traits measured included weekly body weight, egg colour, beak colour and feather colour. Data collected were subjected to one way analysis of variance in a Paternal half sib analysis using Animal model of SAS (2003). Four weeks body weight measurements, egg colour, beak colour and feather colour for 5 sires ranged from 1.29±0.05 1.54±0.07; 2.55±0.02 to 4.00±0.02; 2.45±0.02 to 4.83±0.02 and 1.73±0.02 to 4.58±0.04 respectively. Result: The new Duncan’s multiple range test shows that sire families are similar (p greater than 0.05) in the body weight and beak colour, but significantly differed (p greater than 0.05) in the egg colour and feather colour. The heritability estimates of mature body weight for week 3 was medium, while estimates of heritability for weekly mature body weight for weeks 1, 2 and 4, egg colour, beak colour and feather colour of NHLCE were low heritability. Low h2 of traits suggest that progeny and pedigree selection could be employed for improvement of the egg colour, beak colour and feather colour of NHLCE. The study showed positive genetic correlations between beak colour and egg colour, negative genetic correlations between beak and feather colour. This means that no decision can be taken in isolation as the selection of one trait will have consequences on other traits.

Multiple-trait BLUP: a suitable strategy for genetic selection of Eucalyptus

2018 ◽  
Vol 14 (5) ◽  
Author(s):  
Rodrigo Silva Alves ◽  
João Romero do Amaral Santos de Carvalho Rocha ◽  
Paulo Eduardo Teodoro ◽  
Marcos Deon Vilela de Resende ◽  
Eduardo Pinheiro Henriques ◽  
...  
Keyword(s):  
Genetic Selection ◽  
Multiple Trait ◽  
Selection Of

scholarly journals Model comparison and estimation of genetic parameters for body weight in commercial broilers

2013 ◽  
Vol 93 (1) ◽  
pp. 67-77 ◽  
Author(s):  
G. Maniatis ◽  
N. Demiris ◽  
A. Kranis ◽  
G. Banos ◽  
A. Kominakis
Keyword(s):  
Body Weight ◽  
Akaike Information Criterion ◽  
Model Evaluation ◽  
Model Comparison ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Information Criterion ◽  
Biological Properties ◽  
Genetic Covariance ◽  
Estimation Of Genetic Parameters

Maniatis, G., Demiris, N., Kranis, A., Banos, G. and Kominakis, A. 2013. Model comparison and estimation of genetic parameters for body weight in commercial broilers. Can. J. Anim. Sci. 93: 67–77. The availability of powerful computing and advances in algorithmic efficiency allow for the consideration of increasingly complex models. Consequently, the development and application of appropriate statistical procedures for model evaluation is becoming increasingly important. This paper is concerned with the application of an alternative model determination criterion (conditional Akaike Information Criterion, cAIC) in a large dataset comprising 203 323 body weights of broilers, pertaining to 7 (BW7) and 35 (BW35) days of age. Seven univariate and seven bivariate models were applied. Direct genetic, maternal genetic and maternal environmental (c2) effects were estimated via REML. The model evaluation criteria included conditional Akaike Information Criterion (cAIC), Bayesian Information Criterion (BIC) and the standard Akaike Information Criterion (henceforth marginal; mAIC). According to cAIC the best-fitting model included direct genetic, maternal genetic and c2 effects. Maternal heritabilities were low (0.10 and 0.03) compared to the direct heritabilities (0.17 and 0.21), while c2 was 0.05 and 0.04 for BW7 and BW35, respectively. BIC and mAIC favoured a model that additionally included a direct-maternal genetic covariance, resulting in highly negative direct-maternal genetic correlations (−0.47 and −0.64 for BW7 and BW35, respectively) and higher direct heritabilities (0.25 and 0.28 for BW7 and BW35, respectively). Results suggest that cAIC can select different animal models than mAIC and BIC with different biological properties.

Age of dam and age at measurement adjustments and genetic parameters for scrotal circumference of Canadian Hereford bulls

2003 ◽  
Vol 83 (2) ◽  
pp. 183-188 ◽  
Author(s):  
D. H. Crews Jr. ◽  
D. J. Porteous
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Heritability Estimate ◽  
Positive Association ◽  
Multiple Trait ◽  
Partial Regression Coefficient ◽  
Scrotal Circumference ◽  
Adjustment Factors ◽  
Quadratic Effects

The objective of the study was to estimate age of dam and age at measurement as adjustment factors for scrotal circumference in Canadian Hereford bulls (n = 9029) and to estimate genetic parameters for scrotal circumference, and birth and yearling weights. Quadratic effects of age at measurement and the interaction of age of dam with age at measurement were not important. Adjustment factors recommended for yearling bulls were 1.02, 0.33, 0.10, and 0.16 cm to adjust scrotal circumference of sons of 2-, 3-, 4-, and ≥ 10-yr-old cows to a mature dam (5 to 9 yr of age) equivalent. The linear partial regression coefficient for age at measurement was 0.036 cm d-1. Genetic parameters were estimated using a multiple trait animal model and REML. The heritability estimate for (age of dam and age at measurement) adjusted scrotal circumference was 0.40 ± 0.03, and heritability estimates were 0.43 ± 0.05, 0.21 ± 0.09, and 0.36 ± 0.03 for direct birth weight, maternal birth weight, and yearling weight, respectively. The genetic correlation of adjusted scrotal circumference with direct birth weight was low (0.15), and was moderate (0.38) with yearling weight, but was near zero (-0.01) with maternal birth weight. Environmental and phenotypic correlations of adjusted scrotal circumference were low with birth weight, and were high with yearling weight. These results indicate that there was a positive association between adjusted scrotal circumference and body weight. Genetic improvement of fertility through the use of adjusted scrotal circumference as an indicator trait would not be expected to be antagonistic to that for body weight. Key words: Beef cattle, fertility, Hereford, scrotal circumference

scholarly journals Genetic parameters and selection of biofortified lettuce genotypes based on selection indices

2021 ◽  
Vol 25 (11) ◽  
pp. 772-778
Author(s):  
Luciana A. de Sousa ◽  
Gabriel M. Maciel ◽  
Fernando C. Juliatti ◽  
Igor F. Beloti ◽  
Daniel B. O. Cardoso ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Agronomic Traits ◽  
Stem Diameter ◽  
Germplasm Bank ◽  
Narrow Sense Heritability ◽  
High Magnitude ◽  
Selection Indices ◽  
Number Of Leaves ◽  
High Concentrations ◽  
Selection Of

ABSTRACT Obtaining biofortified vegetables with an emphasis on lettuce is a tool to improve the nutritional status of the population. Selection indices can maximize the simultaneous selection of good agronomic traits and high carotenoid levels. The objective of this study was to estimate the genetic parameters and efficiency of different indices in selecting genotypes of biofortified lettuce with high concentrations of carotenoids and favorable agronomic traits. Statistical analyses were performed on 91 genotypes belonging to the vegetable germplasm bank of the Federal University of Uberlândia, Brazil. The variables analyzed were the chlorophyll index of the leaves, plant diameter, stem diameter, and number of leaves per plant. The values found for narrow sense heritability (h²) ranged from 89.63% (stem diameter) to 96.05% (chlorophyll), showing a high magnitude. The Smith-Hazel index, sum of ranks by the Mulamba & Mock index, direct and indirect selection, and Williams base index were used to predict the selection gains. A total of 17 individuals were selected using the selection methodologies. The Smith-Hazel, Williams, and Mulamba & Mock indices were efficient in showing good direct gains for the evaluated traits. Thirteen genotypes were selected for all indices presenting suitable agronomic traits, which show promise for advancing generations within the breeding program to obtain biofortified lettuce strains.

scholarly journals Effect of the genetic selection of turkeys for increased body weight and egg production on immune and physiological responses

1997 ◽  
Vol 76 (2) ◽  
pp. 289-296 ◽  
Author(s):  
GR Bayyari ◽  
WE Huff ◽  
NC Rath ◽  
JM Balog ◽  
LA Newberry ◽  
...  
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Physiological Responses ◽  
Genetic Selection ◽  
Selection Of

Genetic parameters of growth of Ethiopian Boran cattle

1987 ◽  
Vol 44 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Th. Arnason ◽  
H. Kassa-Mersha
Keyword(s):  
Birth Weight ◽  
Maternal Effects ◽  
Variance Components ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Genetic Covariance ◽  
Weaning Weight ◽  
Genetic Components ◽  
Selection Indices ◽  
The Individual

ABSTRACTRecords on birth weight and pre-weaning growth of 3959 Boran calves, which were progeny of 51 sires and 979 dams, were analysed by least-squares analysis of variance. The variance components for sires, dams and maternal grandsires were estimated from the data. On the basis of assumed genetic correlations −0·44 and −0·55 between direct and maternal effects on birth weight and weaning weight, respectively, the maternal genetic component and the genetic covariance between direct and maternal effects were estimated. The heritabilities for direct effects on birth weight and weaning weight were 0·11 and 0·22, respectively, while the heritabilities of maternal effects were estimated as 0·02 and 0·11, respectively for the same traits. Selection indices for direct and maternal genetic components of weaning weight were constructed for practical use. These selection indices combined information on the individual, the parents and sibs.

scholarly journals Studies in Artificial Selection of Quantitative Characters II. Selection for Body Weight in Drosophila Melanogaster

1963 ◽  
Vol 16 (2) ◽  
pp. 516 ◽  
Author(s):  
BL Sheldon
Keyword(s):  
Body Weight ◽  
Genetic Variability ◽  
Genetic Parameters ◽  
Random Mating ◽  
Environment Interaction ◽  
Genotype Environment Interaction ◽  
Quantitative Characters ◽  
Diallel Crossing ◽  
Selection For ◽  
Selection Of

The method of diallel crossing within a population with random mating was used to estimate genetic parameters for body weight in an Oregon-RO laboratory stock. This showed an absence of additive genetic variability, a high proportion of non-additive genetic variability, and considerable genotype-environment interaction.

Estimates of phenotypic and genetic parameters of some measures of efficiency of milk production in buffaloes

1978 ◽  
Vol 91 (1) ◽  
pp. 181-183
Author(s):  
S. S. Bhalaru ◽  
J. S. Dhillon
Keyword(s):  
Body Weight ◽  
Least Squares ◽  
Milk Production ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Calving Interval ◽  
Lactation Length ◽  
Selection Of

SummaryThe least-squares means for first lactation milk yield, yield per 100 kg of body weight at first calving, yield per day of first lactation length, yield per day of first calving interval and yield per day of age at second calving were 1692 ± 28·2, 339·8 ± 7·30, 5·51 ± 0·97, 3·37 ± 0·81 and 1·07 ± 0·03 kg and the heritabilities of those traits were 0·192 ± 0·086, 0·078 ± 0·078, 0·287 ± 0·096, 0·192 ± 0·086 and 0·305 ± 0·097 respectively. The genetic correlations of first lactation milk yield with various measures of efficiency of milk production (except with yield per 100 kg of body weight) were positive and high (> 0·80). These results indicate that milk yield per day of age at second calving may be used for the selection of buffaloes.

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