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 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.

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 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.

scholarly journals Accuracy of Ranking Individuals in Field Tests of Different Designs: A Computer Simulation

2006 ◽  
Vol 55 (1-6) ◽  
pp. 70-77 ◽  
Author(s):  
Chang-Yi Xie ◽  
Y.-B. Fu ◽  
A. D. Yanchuk
Keyword(s):  
Computer Simulation ◽  
Genetic Variance ◽  
Block Design ◽  
Additive Genetic Variance ◽  
Field Tests ◽  
Incomplete Block ◽  
Single Tree ◽  
Incomplete Block Design ◽  
Variation Patterns ◽  
Site Variation

Abstract A computer simulation was conducted to investigate the accuracy of ranking individual trees in field tests of different designs. A test population that consists of 900 trees from 45 full-sib families generated by three 6-parent disconnected half-diallels was considered. One incomplete block design with single-tree plots and four complete block designs with 1, 2, 4, and 10-tree row plots were examined. Various narrow-sense heritabilities, site variation patterns (patch sizes and gradient slopes), and two levels of dominant to additive genetic variance ratios (0 and 0.30) were evaluated. Results indicate that the accuracy of ranking depends more on the heritability of the trait and less on the magnitude of the dominant genetic variance, site variation patterns, and field designs. With patchy site variation, differences in ranking accuracy were observed for different designs, but became smaller with higher heritabilities. Impact of environmental gradient on the accuracy of individual ranking was negligible. Incomplete block design with single-tree plots (ICB1) provided the most accurate ranking when heritability was low while complete block design with 2-tree plots (RCB2) appeared to be the best when heritability was high. Large row plot designs were among the least effective in all the simulated scenarios. For traits with medium heritabilities, the statistical efficiencies of ICB1 and RCB with 1 and 2-tree plots are comparable.

Factors affecting weight and age at first calving, first lactation milk yield in Gir cows

2016 ◽  
Author(s):  
Basdev Singh ◽  
Pushkraj Sawant ◽  
Dhruvaraj Sawant ◽  
Sachin Todkar ◽  
Richa Jain
Keyword(s):  
Genetic Correlation ◽  
Milk Yield ◽  
Dairy Farm ◽  
Madhya Pradesh ◽  
Age At First Calving ◽  
Factors Affecting ◽  
Phenotypic Correlations ◽  
Heritability Estimates

The present study was undertaken on data of 113 Gir cows maintained at Kasturba Gram Dairy Farm, Indore, Madhya Pradesh, India over a period of 18 years from 1995 to 2012, based on age at first calving. The overall means for weight at first calving (WFC), age at first calving (AFC), and first lactation milk yield (FLMY) were 402.22± 1.28 kg, 1709.04± 51.92 days and 1664.95± 280.72 litres respectively. The heritability estimates for WFC, AFC and FLMY were 0.248± 0.234, 0.307± 0.206 and 0.112± 0.252 respectively. The genetic correlation between WFC and AFC was positive and significant, while it was negative in between WFC and FLMY. The genetic correlation between AFC and FLMY was low and negative. The phenotypic correlations between all traits were positive.

DEVELOPMENT OF DLS BREED OF SHEEP: GENETIC AND PHENOTYPIC PARAMETERS OF DATE OF LAMBING AND LITTER SIZE

1990 ◽  
Vol 70 (3) ◽  
pp. 771-778 ◽  
Author(s):  
MOHAMED H. FAHMY
Keyword(s):  
Key Words ◽  
Genetic Correlation ◽  
Breeding Season ◽  
Litter Size ◽  
Least Square ◽  
Phenotypic Correlation ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations

Least square means, heritabilities, repeatabilities, genetic and phenotypic correlations of date of lambing and litter size in a population of DLS sheep selected for extended breeding season were estimated by different methods. Mean date of lambing for first, second and third parities was 20 Jan., 6 Jan., 31 Dec. and mean litter size was 1.20, 1.25 and 1.41 lambs, respectively. Heritabilities for date of lambing were 0.37 (sire component, 0.25 (sire and dam component), 0.52 (correlation between full sisters) and 0.17 (regression of daughter on dam). For litter size these methods gave the following estimates: 0.17, 0.14, 0.22 and 0.04, respectively. Repeatability estimates averaged 0.21 for date of lambing and 0.24 for litter size. Genetic correlation between the two traits was calculated at −0.38 (sire component), −0.25 (full sisters) and −0.07 (regression of daughter on dam) while the phenotypic correlation was estimated at −0.19 (P < 0.01). Key words: DLS sheep, heritability, repeatability, genetic correlation, phenotypic correlation, date of lambing, litter size

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.

Inheritance of aluminium tolerance in Phalaris aquatica L

1986 ◽  
Vol 37 (4) ◽  
pp. 397 ◽  
Author(s):  
RA Culvenor ◽  
RN Oram ◽  
JT Wood
Keyword(s):  
Genetic Correlation ◽  
Breeding Population ◽  
Solution Culture ◽  
Aluminium Tolerance ◽  
Staining Procedure ◽  
Highly Sensitive ◽  
Sib Families ◽  
Heritability Estimates ◽  
The Difference ◽  
Further Development

The inheritance of aluminium tolerance in P. aquatica was investigated in solution culture, and correlations with other screening systems were determined. In the Israeli cultivar, Noy, the difference between the highly sensitive and moderately tolerant classes, which had been resolved in earlier experiments, can be largely explained by a two-gene hypothesis in which tolerance requires at least one dominant allele at each locus. Modifiers of these genes may also be involved. Assuming that the extensive continuous variation within the moderately tolerant class is polygenic, a quantitative inheritance study was conducted in a population of half-sib families in a diverse breeding population, the sensitive class being eliminated on performance in solution. Heritability estimates for relative root extension in solution ranged from 0.48 to 0.75, and estimated response to selection was high. However, heritability estimates for shoot growth of the same plants on a field site high in aluminium were low and non-significant (0.07-0.26). The highest estimate of genetic correlation between solution and field was not significant at 0.56. Variability in soil aluminium concentrations appeared to be a major cause of these low values. Prior screening of the population using a haematoxylin root-staining procedure gave a significant genetic correlation with solution responses (0.48). However, the technique requires further development for screening phalaris. In breeding for improved tolerance, the highly sensitive class could be eliminated by test crossing potential parents with homozygous sensitive plants. Several generations of selection could then be imposed, which, on the basis of genetic parameters estimated from solution screening, should yield a population appreciably more aluminium-tolerant than existing cultivars.

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