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Genetics Selection Evolution

Open Access

Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance

Genetics Selection Evolution200436:297

Received: 9 April 2003

Accepted: 17 December 2003

Published: 15 May 2004


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.


crossbreedingselectionquantitative trait locimarker assisted selection

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Authors’ Affiliations

Department of Animal Science, Iowa State University, Ames, USA


© INRA, EDP Sciences 2004