Estimated combining Activity of the Pullets Body Weight at 4 and 8 Weeks using Diallel Crossing System

Abstract

Five commercial layers breed (B, C, D, E and F) and one pure breed Rhode Island Red (A) mated using diallel crossing system, The collected data of 4 (Z₁) and 8 (Z₂) week body weight analysed for randomized block design. It was found that a highly significant (P<0.01) was obtained for the hatch effect while non-significant (P>0.05) was obtained for the cross effect. When analyse for GCA and SCA of both traits, a highly significant (P<0.05) were shown except for the SCA of the Z₁ trait. Of these six layers breed, breed A manifested the highest of estimated GCA effect as 0.07571 for Z₁ and 0.07508 for Z2 whereas breed C had the lowest value of both traits. It means that breed C governed less additive gene effect for body weight than the breed A. The specific combining ability variance (σ_si²) of breed C was 27.6586 for the Z₂ trait which was higher than the other breeds. It indicated that there were specific combinations of breed C certain some breeds which yielded considerably more than that would be expected and other combinations which yielded much less than expected. If it is not considered for the egg production trait, the breed C will be selected because of its low body weight would ensured to save the lower feed cost.