WETEROSIS FOR BODYWEIGHT IN NATIVE BY EXOTIC INBRED CHICKEN CROSSES

Abstract

Inbred lines derived from the nativty exotic chicken were compared with their F, and back<-ass populations for body weight. The experimental kinds were raised on deep litter from hatch to 20 weeks of age. Significant heterosis was obtained in body weight to 20 weeks, the magnitude was higher in the reciprocal (native x exotic) than the main (exotic x native) crosses. The backcrosses also exhibited significant heterosis and the magnitude was higher in the native than the exotic back crosses. An analysis of the genetic basis for bodyweight heterosis indicated that while complete dominance of allelic genes influenced the heterosis observed in the native backcrosses, 2-3 loci parental epistasis involving complementary genes were responsible for the heterosis observed in the exotic backcrosses. It is suggested that the genetic gap between the native and exotic chicken could be appreciably reduced by intercrossing the main and reciprocal backcrosses in the next generation. Crisscrossing and selection should follow this