Genet. Sel. Evol.
Volume 36, Number 3, May-June 2004
|Page(s)||297 - 324|
Optimizing purebred selection for crossbred performance using QTL with different degrees of dominanceJack C.M. Dekkers and Reena Chakraborty
Department of Animal Science, 225C Kildee Hall, Iowa State University, Ames, IA, 50011, USA
(Received 9 April 2003; accepted 17 December 2003)
A method was developed to optimize simultaneous selection for a quantitative trait with a known QTL within a male and a female line to maximize crossbred performance from a two-way cross. Strategies to maximize cumulative discounted response in crossbred performance over ten generations were derived by optimizing weights in an index of a QTL and phenotype. Strategies were compared to selection on purebred phenotype. Extra responses were limited for QTL with additive and partial dominance effects, but substantial for QTL with over-dominance, for which optimal QTL selection resulted in differential selection in male and female lines to increase the frequency of heterozygotes and polygenic responses. For over-dominant QTL, maximization of crossbred performance one generation at a time resulted in similar responses as optimization across all generations and simultaneous optimal selection in a male and female line resulted in greater response than optimal selection within a single line without crossbreeding. Results show that strategic use of information on over-dominant QTL can enhance crossbred performance without crossbred testing.
Key words: crossbreeding / selection / quantitative trait loci / marker assisted selection
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© INRA, EDP Sciences 2004