Utilization of Nigerian Native Pig in Breeding 1. A Genetic Assessment of Crossbred Heterosis in Growth and Litter Size

摘要

The Nigerian native pig and 2 exotic breeds-Landrace and Large White were compared with their F1 and F1 by parental breed backcross populations for a range of growth and litter size traits to 40 weeks of age. Experimental pigs were raised intensively in a standard piggery pens during growth. The results showed outward demonstration of significant superiority by the exotic parental group, the F1 group and the F1?exotic backcross (Mainbackcross group) over and above that of the natives, the F1?native backcrosses (reciprocal backcross group) in most of the characters monitored especially that of growth and litter size. An analysis of the genetic basis for heterosis of growth and litter size indicated that the native by exotic 2-loci parental epistasis was responsible for the low residual heterosis observed among the backcross genotypes. Litter size heterosis was low and negative among the crossbred populations. Based on the genetic parameters estimated, hybrid vigour in all generations subsequent to F1 can be stepped up satisfactorily by adopting the Back and Criss-Cross heterosis Evaluation strategy (BAC-CET) being proposed.