Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance.
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.
Dekkers
Jack C M
JC
Department of Animal Science, 225C Kildee Hall, Iowa State University, Ames, IA 50011, USA. jdekkers@iastate.edu
Chakraborty
Reena
R
D000483:Alleles; D000818:Animals; D002417:Cattle / Q000235:genetics*; D003433:Crosses, Genetic; D005260:Female; D005787:Gene Frequency; D005799:Genes, Dominant; D005828:Genetics, Population; D006824:Hybridization, Genetic; D007178:Inbreeding; D008297:Male; D018895:Microsatellite Repeats; D008957:Models, Genetic; D010641:Phenotype; D019655:Quantitative Trait, Heritable; D012641:Selection, Genetic