A total number of 1833 day old chicks of mixed sex of Mandarah (MM), El-Salam (SS) were used as well as their crosses and reciprocal crosses. Body weight (BW), daily weight gain (WG), relative growth rate (RGR), feed consumption (FC), feed conversion ratio (FCR), shank length (SL), keel length (KL) and body circumferences (BC) were evaluated among the four studied lines form hatch up to 20 weeks of age. SM cross showed superiority of BW with positive heterosis percentages; while negative heterosis percentages were recorded for MS cross. Also, SM cross recorded the highest WG at 4, 12 and 16 weeks of age with high positive heterosis percentages up to 16 weeks of age, high overall RGR from 0-8 and 0-12 weeks of age with corresponding heterosis percentages (0.46 and 0.73%). SM cross showed the highest FC compared to other lines and recorded positive heterosis percentage. On the other hand, SM cross and SS line showed the highest significant differences for SL and KL at 4, 8 and 12 weeks of age with positive heterosis percentages for SM line, but no effect for crossing present on BC. Positive maternal effects were recorded for most of the growth traits. It was concluded that, using El-Salam strain as a sire line and Mandarah strain as a dam line resulted in SM cross of improved growth performance traits.
El-Salam, Mandarah, Crossing, Growth traits, Heterosis, Maternal effect.