Heterosis for egg production in native by exotic by inbred chicken crosses

Abstract

Inbred lines generated from the native and exotic chickens were compared with their F1 and backcross populations for a range of short term egg production traits. The experimental birds were brooded for 8 weeks and raised on a deep litter pens from 8 to 40 weeks of age. Age at first eggs were longer in the crossbred groups and the delay was mostly caused by the dominant genes from the exotic parents. Highly significant (P>0.01) heterosis were obtained by the crossbred groups in hen day rate and total egg mass respectively. The heterosis observed in the crossbred groups for egg weight was low and mostly non significant. the backcross groups recorded residual heterosis in egg production traits ( hen day rate, total egg mass and egg weight) and the magnitude was higher in the exotic than the native backcrosses. The results further indicate that the egg production performance of the crossbred groups were mostly influenced by maternal, sex linked, dominance and epistatic gene effects. It was suggested that the egg production potential of the native chicken could be improved further by cross mating-selected native and exotic backcross groups. This should be followed by crisscrossing.