Relative efficiency of family index versus reciprocal recurrent selection for improving egg production in White Leghorn

Data on 5259 & 4442 pullets of IWH and IWI lines respectively under family index selection (Index) and 4760 & 3155 pullets of IWH and IWI lines, respectively under reciprocal recurrent selection (RRS) over six generations were analyzed. The average number of sire, dam and female progeny tested per generation were 37.14, 149.29 & 751.28 in IWH (Index); 36.29, 140.43 & 634.37 in IWI (Index); 34.86, 132.57 & 680.00 in IWH (RRS) and 33.57, 11 1.86 & 450.71 in IWI (RRS) lines, respectively. The effective population size and rate of inbreeding per generation were 118.94 & 0.44% in IWH (Index); 115.35 & 0.45% in IWI (Index); 110.41 & 0.48% in IWH (RRS) and 103.28 & 0.51% in IWI (RRS) lines, respectively. Genetic correlation between purebred and straincross paternal half-sibs for part period egg production were highly positive (0.87 & 0.38) indicating the superiority of family index over reciprocal recurrent selection. The total genetic gains for part period egg production in pure lines and crossbreds were higher under family index than reciprocal recurrent selection. The present study indicated the overall superiority of family index method of selection over RRS for six generations of data.