J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Anim Sci. 1976. 42:291-298.
© 1976 American Society of Animal Science
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bruns, E.
Right arrow Articles by Harvey, W. R.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Bruns, E.
Right arrow Articles by Harvey, W. R.

Effects of Varying Selection Intensity for Two Traits on Estimation of Realized Genetic Parameters

Erich Bruns1 and Walter R. Harvey

The Ohio State University, Columbus 43210

Abstract

A Monte Carlo study with a variance-covariance components model was carried out in order to determine how differential attention given to two traits under simultaneous selection affects the accuracy of estimates of realized genetic parameters. Three different sets of genetic, maternal and environmental parameters and three different sets of index weights for the two traits were used in the simulation. Selection was practiced for nine generations for each of the nine combinations of parameter sets and index weights in two separate lines with 10 sires, 20 dams and 80 offspring each generation in each line. Each combination was replicated 50 times.

Estimates of heritability for the two traits were found to be biased downwards and the genetic correlation estimates were biased upwards because of reductions in the genetic variance due to selection of parents. An adjustment of the selection differentials is suggested which was successful in eliminating the bias in estimating heritability, though not genetic correlations.

Increasing the attention given to a particular trait in selection slightly reduced the bias and the standard error for the estimate of heritability for that trait. However, the standard error for the estimate of heritability for the other trait increased substantially. Also, the smallest standard errors of the genetic correlation estimates were found when equal attention was given to the two traits. Hence, it was concluded that genetic parameters are most efficiently estimated from selection experiments when equal attention is given to the two traits. Whether this is true for combinations of genetic parameters not considered in this study remains uncertain.

Footnotes

1 Present address: Institut für Tierzucht und Haustiergenetik, Universität Göttingen, 3400 Göttingen, Albrecht-Thaer Weg 1, West-Germany.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1976 by the American Society of Animal Science.