Genetic and Environmental Correlations between the Growth Rates of Pigs at Different Ages

Hazel, L. N.; Baker, Marvel L.; Reinmiller, C. F.

doi:10.2527/jas1943.22118x

Cited by 96 publications

(41 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The approximate standard errors of individual heritabilities were estimated according to Wright (1976). Genetic correlations (rg) were calculated from estimates of additive genetic variances and covariances following Hazel et al (1943) and the standard errors of these correlations according to Tallis (1959). No assumption regarding the coefficient of relationship is required for estimating genetic correlations.…”

Section: Cr} H~= O~ +O~+o2mentioning

confidence: 99%

Genetic parameters and expected gains from selection for monoterpene yields in Petford Eucalyptus camaldulensis

Doran

Matheson

1994

New Forest

View full text Add to dashboard Cite

Application. Yields of 1,8-cineole and total monoterpenes (as a fraction of leaf weight) from the leaves of 3.75-year-old open-pollinated progeny of Petford E. camaldulensis were highly heritable. Through individual tree selection, substantial improvements in 1,8-cineole yield, the essential oil trait of most commercial interest, and growth rates can be achieved concurrently thus enhancing the economics of growing Petford E. camaldulensis for wood and oil.Abstract. Genetic parameters were estimated for yield of 1,8-cineole and total monoterpenes as a fraction of leaf weight in nineteen open-pollinated families of Petford origin at 3.75 years in two progeny/provenance trials of E. camaldulensis in Zimbabwe. Both traits appear to be highly heritable and, as expected, were strongly genetically correlated, with narrow-sense individual heritabilities near 0.50. Expected gain in the first generation following individual selection in the trials of one tree in 10 for either trait is about 25--32%.Genetic correlations between growth traits and 1,8-cineole yield were small. This indicates that both traits might be improved concurrently thus enhancing the economics of growing Petford E. camaldulensis for wood and medicinal oil. However, the presence of moderate and unfavourable genetic correlations between growth traits and total yield of monoterpenes warrants further study. It was not possible to gauge the significance of apparent family × site interaction for 1,8-cineole yield in this study. However, a test of rank correlation showed an association (Ip < 0.01) between family rankings on each site and the highest-yielding trees on both sites came from the same families. This raises the possibility of being able to select individuals for cloning that yield well over a range of site conditions.

show abstract

Section: Cr} H~= O~ +O~+o2mentioning

confidence: 99%

Genetic parameters and expected gains from selection for monoterpene yields in Petford Eucalyptus camaldulensis

Doran

Matheson

1994

New Forest

View full text Add to dashboard Cite

show abstract

“…The methods of calculating the genetic correlation were that of covariance outlined by Hazel et al (1943) and the analysis of variance outlined by Robertson (1959), Dickerson (1962) and Yamada (1962). The analysis of variance yields expected values identical with those of covariance.…”

Section: Two-way Selection In Tribolium 311mentioning

confidence: 99%

Two-way selection for body weight in Tribolium on two levels of nutrition

Hardin

Bell

1967

Genet. Res.

View full text Add to dashboard Cite

Parameters necessary for predicting direct and correlated responses for large and small 13-day larval weight in T. castaneum on two levels of nutrition were estimated in the base population. Larval weight in the GOOD environment was approximately twice that observed in POOR. Heritabilities (estimated from the ratio of sire component to total phenotype variance) of larval weight on the two rations were similar, 0·21 ± 0·06 and 0·19 ± 0·05 for GOOD and POOR, respectively. Heritabilities based on dam-offspring covariances were similar to these, but those obtained from full-sib covariances were much larger (0·97 ± 0·07 for GOOD and 0·69 ± 0·07 for POOR). This suggested that considerable dominance rather than maternal effects were present. The genetic correlation between growth on GOOD and growth on POOR was estimated as + 0·60 ± 0·21.The selection experiment was replicated four times with each replication extending over eight generations. Good agreement between predicted and observed values for direct selection was observed for large selection in both environments and small selection in POOR. However, response to small selection in GOOD was significantly greater than predicted in all four replications and was associated with increased selection differentials. Realized heritabilities were approximately the same for both directions in GOOD yet asymmetrical responses occurred for all replications due to unequal selection differentials. On the other hand, realized heritabilities were asymmetrical in POOR. Those observed for small selection were more than twice the size of those calculated for large lines. However, the responses in POOR were symmetrical since the selection differentials varied inversely with the realized heritabilities.Because of the asymmetry observed for heritabilities and selection differentials, correlated responses were poorly predicted. The average effective genetic correlation between growth in GOOD and growth in the POOR environment agreed remarkably well with the base estimate, yet asymmetry of the genetic correlation was a consistent phenomenon with values for the large lines being less than the base parameter while small lines were uniformly larger.Asymmetries of the various genetic parameters were not anticipated from base estimates. They were not caused by sampling or chance fluctuations since all four replications were remarkably consistent. Asymmetry for any one genetic parameter (e.g. heritability) was associated with a particular environment or direction of selection while other genetic parameters reacted asymmetrically in populations exposed to a different set of environmental treatments.For maximum performance in a single environment, these results show that selection should be practiced in that environment. With regard to mean performance in GOOD and POOR environments, selection for large size in POOR gave some 25% more gain than selection in GOOD. Selection for small size in either environment was equally effective in obtaining minimum size in both environments.

show abstract

“…However, the application of the methods used in calculating the intraclass correlation has varied somewhat from that of calculating the correlation between repeated measurements on the same individual. The direct application of the intraclass correlation to a genetic situation is that of analyzing the progeny records for a given set of sires by the "among sire" and "within sire" paternal half-sib analysis (Hazel _et al, 1943;Kempthorne, 1957).…”

Section: Ct^h + Ct^p + Ct^tmentioning

confidence: 99%

“…The "among sire" and "within sire" paternal half-sib analysis of variance and covariance, using the same notation as in 2 2 Table 12 with g D = g S, is one of the more useful analyses in deriving estimates of such items as heritability, genetic, phenotypic, and environmental correlations if certain assump tions are valid (Hazel _et al , 1943;Koch, 1953;Swiger, 1960). 2_ § » by 4 therefore estia^S + a^W mated heritability in the narrow sense (Lush, 1948).…”

Section: Ct^h + Ct^p + Ct^tmentioning

confidence: 99%

Beef calf weights at 100 days and 205 days as indicators of dams' producing ability

Drewry

View full text Add to dashboard Cite

Genetic and Environmental Correlations between the Growth Rates of Pigs at Different Ages

Cited by 96 publications

References 0 publications

Genetic parameters and expected gains from selection for monoterpene yields in Petford Eucalyptus camaldulensis

Genetic parameters and expected gains from selection for monoterpene yields in Petford Eucalyptus camaldulensis

Two-way selection for body weight in Tribolium on two levels of nutrition

Beef calf weights at 100 days and 205 days as indicators of dams' producing ability

Contact Info

Product

Resources

About