scholarly journals Laboratory estimates of heritabilities and genetic correlations in nature.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 865-871 ◽  
Author(s):  
B Riska ◽  
T Prout ◽  
M Turelli
Keyword(s):  
Lower Bound ◽  
Genetic Correlation ◽  
Lower Bounds ◽  
Natural Environment ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Phenotypic Correlations ◽  
Significant Genetic Correlation ◽  
Genetic And Phenotypic Correlations

Abstract A lower bound on heritability in a natural environment can be determined from the regression of offspring raised in the laboratory on parents raised in nature. An estimate of additive genetic variance in the laboratory is also required. The estimated lower bounds on heritabilities can sometimes be used to demonstrate a significant genetic correlation between two traits in nature, if their genetic and phenotypic correlations in nature have the same sign, and if sample sizes are large, and heritabilities and phenotypic and genetic correlations are high.

Heritabilities and genetic and phenotypic correlations for height and diameter in coastal Douglas-fir

1982 ◽  
Vol 12 (2) ◽  
pp. 181-185 ◽  
Author(s):  
Francis C. Yeh ◽  
Chris Heaman
Keyword(s):  
Genetic Correlation ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Growing Season ◽  
Breeding Population ◽  
Douglas Fir ◽  
Single Tree ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

Factorial crosses of 22 seed trees and 4 pollen parents from a breeding population of 445 coastal Douglas-firs were tested at two sites. Analyses of heights and diameters after the sixth growing season indicated only the significance of additive genetic variance. The single tree heritability estimates for height and diameter were 0.10 ± 0.07 and 0.12 ± 0.08, respectively. The genetic correlation between height and diameter was 0.81 ± 0.64.

scholarly journals Realized Sampling Variances of Estimates of Genetic Parameters and the Difference Between Genetic and Phenotypic Correlations

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1409-1416 ◽  
Author(s):  
Kenneth R Koots ◽  
John P Gibson
Keyword(s):  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Parameter Estimates ◽  
Sampling Variance ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.

Genetic parameter estimates (full sib and half sib analysis) of fertility and hatchability in two strains of Rhode Island chickens

2021 ◽  
Vol 38 (1) ◽  
pp. 14-22
Author(s):  
M. Orunmuyi ◽  
I. A. Adeyinka ◽  
O.O Oni
Keyword(s):  
Rhode Island ◽  
Additive Genetic Variance ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Parameter Estimates ◽  
Phenotypic Correlations ◽  
Poultry Breeding ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

A study was conducted to estimate the genetic parameters of fertility and hatchability in two strains of Rhode Island Red (RIR) Chickens denoted as Strain A and Strain B respectively using the full-sib (sire +dam variance) and maternal half-sib (dam variance) components. The birds were obtained from the selected populations of RIR Chickens kept at the poultry breeding programme of National Animal Production Research Institute, Shika, Zaria, Nigeria. Settable eggs were collected from mating 28 cocks to 252 hens in a ratio of 1cock:9 hens from each strain. Eggs were pedigreed according to sire and dam. Results showed that values obtained for number of egg set (EGGSET), number of fertile eggs (NFERT), number of hatched chicks (NHATCH), percentage of chicks hatched from total eggs set (PHATCH) and percentage of chicks hatched from fertile eggs (PHATCHBL) were all higher in strain A than strain B. Heritability estimates obtained from the full-sib and maternal half-sib analysis ranged from medium to high for the two strains (0.24-0.96). The maternal half sib estimates were higher (0.40-0.96) than the estimates obtained from full sibs (0.24- 0.48). Genetic and phenotypic correlations obtained for both strains were positive and similar regardless of method of estimation. Genetic correlations between EGGSET and PFERT were low in strain A using both full-sib and maternal half-sib analyses (0.09-0.14). Phenotypic correlations between EGGSET and PFERT, PHATCH and PHATCHBL were also low in both strains and regardless of method of analyses. Moderate to high heritability estimates suggest that genetic improvement can be obtained by selection of these reproductive traits. The full-sib analysis for estimating heritability will be preferred since it is assumed that only additive genetic variance contributes to the covariance between family members.

scholarly journals Estimates of genetic correlations and correlated responses to selection in cashew (Anacardium occidentale L.)

1998 ◽  
Vol 21 (3) ◽  
pp. 398-402 ◽  
Author(s):  
Diógenes Manoel Pedroza de Azevedo ◽  
João Ribeiro Crisóstomo ◽  
Francisco Célio Guedes Almeida ◽  
Adroaldo Guimarães Rossetti
Keyword(s):  
Genetic Variance ◽  
Genetic Correlations ◽  
Anacardium Occidentale ◽  
Correlated Responses ◽  
Population Means ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Variance Estimates ◽  
Good Possibility ◽  
East West

The present study estimates variances and genetic and phenotypic correlations for five traits in 27 progenies of cashew trees (Anacardium occidentale L.). Data were obtained from a trial conducted in 1992 at Pacajus, Ceará, experimental station of Embrapa Agroindústria Tropical. The characters studied were plant height (PH), North-South and East-West canopy spreads (NSS, EWS), and primary and secondary branch numbers (PBN, SBN). All genetic and phenotypic correlations presented positive and significant values. Selection to increase or decrease the average of any one of the five characteristics of cashew plants in the progenies studied affected the average of the others. The 16-month-old canopy spread can be predicted from NSS or EWS since correlations between them were high. Correlations between PH and SBN were low, indicating that there is a good possibility of obtaining smaller plants without causing drastic reductions in SBN. PH and SBN showed, respectively, the lowest and highest genetic variance estimates relative to the corresponding population means.

HERITABILITY OF TEAT NUMBER IN SWINE

1990 ◽  
Vol 70 (2) ◽  
pp. 425-430 ◽  
Author(s):  
R. M. McKAY ◽  
G. W. RAHNEFELD
Keyword(s):  
Key Words ◽  
Genetic Correlation ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Data Set ◽  
Phenotypic Correlations ◽  
Teat Number ◽  
Genetic And Phenotypic Correlations ◽  
Time Periods ◽  
Selection For

Heritabilities were estimated for teat number in nine populations of swine over two time periods. From 1962 to 1974 the populations included Lacombe, Yorkshire, and Lacombe × Yorkshire. In this data set, only total teat number was recorded. From 1982 to 1988 three purebred populations (Landrace, Yorkshire, and Hampshire) and three crossbred populations (Landrace-Yorkshire rotation, Landrace × Yorkshire, and Landrace × Hampshire) were represented and total teat number and the number of teats anterior and posterior to the navel were recorded. Heritabilities for total teat number were greater in the 1982–1988 data (ranging from 0.27 to 0.47) than in the 1962–1974 data (ranging from 0.20 to 0.32). The heritability of posterior teat numbers (ranging from 0.08 to 0.39) was generally larger than the heritability of anterior teat numbers (ranging from 0.03 to 0.21) and both were considerably less than the heritability of total teat number. Genetic and phenotypic correlations were calculated for the relationships between anterior and posterior teat numbers (AP), anterior and total teat numbers (AT), and posterior and total teat numbers (PT). The relative magnitudes of the genetic and phenotypic correlations with respect to AP, AT, and PT revealed that selection for increased total teat number would increase the number of anterior and posterior teats. However, the larger genetic correlations for PT relative to AT would lead to a greater increase in posterior teat number than anterior teat number. Key words: Pigs, teat number, heritability, genetic correlation, phenotypic correlation

Evaluation of repeatability and pre-structured repeatability models for genetic analyses of repeated records of fat and protein contents of milk in Iranian Holstein cows

2018 ◽  
Vol 58 (11) ◽  
pp. 1983
Author(s):  
M. Asadi Fozi
Keyword(s):  
Genetic Analysis ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Holstein Cows ◽  
Phenotypic Correlation ◽  
Genetic Covariance ◽  
Future Studies ◽  
Phenotypic Correlations ◽  
Variance Structure

Fat and protein content of milk measurements from first to fifth lactations of Iranian Holstein cows were analysed using repeatability and several pre-structured repeatability models that varied in additive genetic variance structure and fitted heterogeneous residual co (variance). For this research, a total of 257 197 fat and 218 688 protein records were used. The records were measured on 116 531 cows born between 2010 and 2014. The animals originated from 2355 sires and 91 212 dams. Pre-structured repeatability models with heterogeneous residual co (variance) and the respective genetic variance structure were the best models for genetic analysis of the fat and protein data. The results derived from these models showed that heritability of both fat and protein are decreased from first to fifth lactations. Heritability of fat measured at first, second, third, fourth and fifth locations were between 0.10 and 0.19 and those for protein were between 0.07 and 0.24. Moderate to high phenotypic correlations were estimated between the repeated records of the fat and protein. Values of 0.13 and 0.16 were estimated for heritability of fat and protein using repeatability model. Phenotypic correlations among the repeated records of fat and protein were estimated to be 0.30 and 0.33, respectively when this model was applied. The results showed the genetic variance, heritability and phenotypic correlation of the fat and protein are changed over the lactations but the genetic parameters derived from the repeatability model are homogenous whereas in both models unity genetic correlations are assumed among the repeated records. The results of this study show that the repeatability model is not an appropriate model for genetic analysis of the repeated records of fat and protein in the population investigated and can be improved when pre-structured repeatability model is used. In the present study homogenous genetic covariance was assumed among the fat and protein taken at the different lactations which can be modelled in future studies for more improving the models.

scholarly journals Genetic and phenotypic aspects of the body measured traits in merinolandschaf breed of sheep

2012 ◽  
Vol 28 (4) ◽  
pp. 733-741 ◽  
Author(s):  
M.P. Petrovic ◽  
V. Caro-Petrovic ◽  
D. Ruzic-Muslic ◽  
Z. Ilic ◽  
Z. Spasic ◽  
...  
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Body Length ◽  
Genetic Correlations ◽  
The Body ◽  
Sheep Breed ◽  
Standard Errors ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Linear Body

Merinolandschaf sheep breed was used to estimate relationship between the next traits: Body weight of adult ewes (BW), Height to withers (HW), Body length (BL), Girth of Chest (GC), Rump Width (RW), Body weight of lambs at birth (BWB), Body weight of lambs at weaning (BWW). The collected data were from 750 sheep and their lambs during the period of three year. Estimates of means and standard errors for linear body measures and body weight of adult ewes and lambs, were obtained using the software program SPSS (2006). To estimate genetic and phenotypic correlations of observed traits, the ASREML program was used. Research has shown that genetic correlations between BW and all body measures of dams, ranging from 0.728 (BW-GC) to 0.976 (BW-HW). Genetic correlation between body measures of dams have also been positive and ranged in the interval from 0.873 (HW-GC) to 0.999 (BL-GC). Values for phenotypic correlations were lower compared with the genetic and the range varied from 0.183 (RW-BWB) to 0.421 (GC-BWW). The weaker phenotype correlations can be interpreted as play of more complex genetic and residual factors.

scholarly journals Sapling and coppice biomass heritabilities and potential gains from Eucalyptus polybractea progeny trials

2021 ◽  
Vol 17 (2) ◽  
Author(s):  
Beren Spencer ◽  
Richard Mazanec ◽  
Mark Gibberd ◽  
Ayalsew Zerihun
Keyword(s):  
Western Australia ◽  
Growth Rates ◽  
Genetic Parameters ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Short Rotation ◽  
Sapling Growth ◽  
Genetic And Phenotypic Correlations ◽  
Breeding Selections ◽  
Cross Site

AbstractEucalyptus polybractea has been planted as a short-rotation coppice crop for bioenergy in Western Australia. Historical breeding selections were based on sapling biomass and despite a long history as a coppice crop, the genetic parameters of coppicing are unknown. Here, we assessed sapling biomass at ages 3 and 6 from three progeny trials across southern Australia. After the second sapling assessment, all trees were harvested. Coppice biomass was assessed 3.5 years later. Mortality following harvest was between 1 and 2%. Additive genetic variance for the 6-sapling estimate at one site was not significant. Sapling heritabilities were between 0.06 and 0.36 at 3 years, and 0.18 and 0.20 at 6 years. The heritability for the coppice biomass was between 0.07 and 0.17. Within-site genetic and phenotypic correlations were strong between all biomass assessments. Cross-site correlations were not different from unity. Selections based on net breeding values revealed positive gains in sapling and coppice biomass. Lower or negative gains were estimated if 3-year sapling selections were applied to the coppice assessments (−7.1% to 3.4%) with useful families culled. Positive gains were obtained if 6-year sapling selections were applied to the coppice assessment (6.4% to 9.3%) but these were lower than those obtained by applying coppice selections to the coppice assessment (8.4% to 14.8%). Removal of poor performing families and families that displayed fast sapling growth rates but under-performed as coppice will benefit potential coppice production. These results indicate that selections should be made using coppice data.

Genetic evaluation of production traits between and within flocks of Merino sheep. I. Hogget fleece weights, body weight and wool quality

1989 ◽  
Vol 40 (2) ◽  
pp. 433 ◽  
Author(s):  
SI Mortimer ◽  
KD Atkins
Keyword(s):  
Body Weight ◽  
Environmental Effects ◽  
Genetic Variance ◽  
Research Centre ◽  
Production Traits ◽  
Merino Sheep ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Fleece Weight

Wool production traits were measured on Merino hogget ewes in an unselected multiple-bloodline flock over a 7-year period at Trangie Agricultural Research Centre, N.S.W. The traits measured were greasy fleece weight (GFW), skirted fleece weight (SKFW), yield (Y), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). These measurements were used to examine genetic differences between and within flocks of Merino sheep, and to estimate heritability of and genetic and phenotypic correlations among these traits. Significant strain, flock within strain and flock effects were present for all traits. Interactions between these effects and year were non-significant. Within-flock genetic variance was always larger than between-flock within strain genetic variance for each trait. The influence of environmental effects on these traits was also examined. The environmental effects of birth-rearing type, age at observation and age of dam together accounted for about 7-10% of the total within-flock variation in fleece weights and body weight.After adjusting for significant environmental effects, paternal half-sib heritability estimates were 0.29 �. 0.06 for GFW, 0.22 � 0.05 for SKFW, 0.35 � 0.05 for Y, 0.30 �0.06 for CFW, 0.48 �0.07 for FD, 0.34 �. 0.06 for BWT and 0.44 �0.07 for SL. Estimates for genetic and phenotypic correlations were in agreement with published estimates except for the genetic correlation between CFW and FD (0.40 �. 0.11), and the genetic correlations involving BWT, which were essentially zero. The implications of the results of this study for the genetic improvement of Merino sheep for wool production are discussed.

Genetic parameters of Barki sheep raised under semi-arid conditions

1969 ◽  
Vol 11 (3) ◽  
pp. 361-367 ◽  
Author(s):  
M. H. Fahmy ◽  
E. Salah E. Galal ◽  
Y. S. Ghanem ◽  
S. S. Khishin
Keyword(s):  
Genetic Parameters ◽  
Genetic Correlations ◽  
Research Station ◽  
Phenotypic Correlations ◽  
Arid Conditions ◽  
Body Weights ◽  
Genetic And Phenotypic Correlations ◽  
Fleece Weight ◽  
Semi Arid ◽  
Desert Research

SUMMARYRecords on 695 lambs were collected over a period of 5 years from 1961/62 to 1965/66, at Ras El-Hekma Desert Research Station, 230 km west of Alexandria. The characters studied were birth, weaning and yearling body weights, pre- and post-weaning daily gains and greasy fleece weight.Birth, 120-day and 365-day body weights were 3·4, 18·2 and 33·4 kg respectively. Greasy fleece weight at 16 months of age was 3·29 kg. Heritability estimates of birth, weaning, yearling weights, pre- and post-weaning daily gains and greasy fleece weight were 0·22, 0·45, 0·41,0·45 and 0·29 respectively. Genetic and phenotypic correlations between birth, weaning and yearling weights were all positive and significant. Genetic correlations between fleece weight and body characteristics were negative and low.

Sign in / Sign up

Export Citation Format

Share Document