Genetic correlation between purebred and crossbred half sibs*

The data on performance traits of the pullets of two purebred strains (H & C) and their reciprocal crosses raised in multiple hatches over six generations (1994–2000) of crossbred selection were analyzed. Genetic correlation (r_PC) between paternal purebred and crossbred half sisters for body weights at 20 and 40 weeks of age, age at first egg, egg number to 40 weeks of age, and egg weight during 39–40 weeks of age was estimated using sire component of variance and covariance. Genetic correlation for 20 week body weight was positive in all generations except in 5^th generation and the corresponding estimates for 40 weeks body weight were positive in all the generations. For age at first egg, correlation was negative (−0.739, -0,1703, -0.0410) in first three generations, whereas r_PC, for egg number was low and negative in last two generations. Correlation for egg weight was medium in 5^th generation and negative for first three generations. Increase in correlations for body weights and egg number in 3^rd generation was evident. In general, it was concluded that r_pc was low to medium for all the traits indicating the importance of non-additive gene action. The changes in the magnitude of correlation for traits under study among six generations were erratic and no specific conclusion could be drawn, The possible reason may be a small and unequal number of purebred and crossbred progenies of a sire.