: A selection program for four generations (base and three selected generations)
was started in 2011 in Benha University, Egypt to improve egg production traits in a synthetic
line named Benha chickens. A total of 18 cockerels and 180 pullets were selected from Benha
base population (control) according to their BLUP values for egg number during 90 days of laying
Data of 756 pedigreed hens were used to obtain estimates of heritability, genetic and phenotypic
correlations and BLUP for egg production traits, age (ASM) and body weight at sexual maturity
(BWSM), weight of the first egg (WFE), egg number (EN), rate of laying (RL), egg mass (EM)
recorded during 90 days (EM90D) and 120 days (EM120D) of production after sexual maturity.
The selection effects, correlated responses and the genetic and phenotypic trends for egg
production traits across generations were quantified and clarified applying the updated approach
of the animal model program of BLUPF90. Heritability estimates were moderate; being 0.27,
0.32, 0.42, 0.31, 0.34, 0.28, 0.33, 0.14 and 0.19 for ASM, BWSM, WFE, EN90D, EM90D,
EN120D, EM120D, RL90D and RL120D, respectively. The ranges in BLUP of most egg
production traits in the control generation were higher than those estimates in the selected
generations. Accuracies of BLUP estimates for egg production traits in all generations (control
and selected) were moderate or high. The three selected generations were superior in most egg
production traits than the base generation (P