Study of early selection in tree breeding. 2. Advantage of early selection through shortening the breeding cycle. Wu, H. X. Silvae genetica, 48(2):78–83, January, 1999.
abstract   bibtex   
Three main advantages from early selection in tree breeding have been recognized: 1.) increased selection intensity or reduc- ed field-testing size; 2.) shorter generation interval; and 3.) genetic information from early testing can be used to enhance selection efficiency at later ages. The second advantage is obtained through quicker realisation of genetic gain or by breeding several generations within a conventional breeding cycle from mature selection. To quantify the second advantage from early selection it is necessary to estimate genetic gain from indirect selection over several generations. In this paper, a method is derived to estimate genetic gain from several gen- erations of early indirect selection and is used to study the advantage of early selection through shortening the tree breed- ing cycle relative to mature selection. The results show that genetic variance, heritability and selection response for the cor- related (mature) trait as well as genetic correlation between directly selected (early) and correlated (mature) traits will decline after each generation of selection. When the number of generations approaches infinity, genetic variance, heritability and selection response for the correlated trait and the genetic correlation between directly selected and correlated traits each approach corresponding limiting values under F ISHER’s infinite genetic loci model. The reduction in genetic variance, heritabil- ity and selection response for the correlated trait is slower than the reduction of genetic variance for the trait under direct selection. The method is applied to a lodgepole pine early selec- tion study.
@article{wu_study_1999,
	title = {Study of early selection in tree breeding. 2. {Advantage} of early selection through shortening the breeding cycle},
	volume = {48},
	issn = {0037-5349},
	abstract = {Three main advantages from early selection in tree breeding
have been recognized: 1.) increased selection intensity or reduc-
ed field-testing size; 2.) shorter generation interval; and 3.)
genetic information from early testing can be used to enhance
selection efficiency at later ages. The second advantage is
obtained through quicker realisation of genetic gain or by
breeding several generations within a conventional breeding
cycle from mature selection. To quantify the second advantage
from early selection it is necessary to estimate genetic gain
from indirect selection over several generations. In this paper,
a method is derived to estimate genetic gain from several gen-
erations of early indirect selection and is used to study the
advantage of early selection through shortening the tree breed-
ing cycle relative to mature selection. The results show that
genetic variance, heritability and selection response for the cor-
related (mature) trait as well as genetic correlation between
directly selected (early) and correlated (mature) traits will
decline after each generation of selection. When the number of
generations approaches infinity, genetic variance, heritability
and selection response for the correlated trait and the genetic
correlation between directly selected and correlated traits each
approach corresponding limiting values under F ISHER’s infinite
genetic loci model. The reduction in genetic variance, heritabil-
ity and selection response for the correlated trait is slower than
the reduction of genetic variance for the trait under direct
selection. The method is applied to a lodgepole pine early selec-
tion study.},
	language = {eng},
	number = {2},
	journal = {Silvae genetica},
	author = {Wu, H. X.},
	month = jan,
	year = {1999},
	keywords = {⛔ No DOI found},
	pages = {78--83},
}

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