EFFECT OF REPEATED BACKCROSSING FOR TWO GENERATIONS BETWEEN THE LOCAL BLACK BALADI AND WHITE NICHOLAS TURKEYS ON EGG PRODUCTION AND HATCH TRAITS 2- HATCH TRAITS AND FITNESS INDEX

The study investigated backcrossing effects for hatch traits and fitness index using two strains of turkey, Black Baladi (BB) and commercial White Nicholas (WW) as well as their reciprocal crosses through three successive years.
There were highly significant differences among the different genotypes for fertility percentage (F %), hatchability percentages of fertile eggs (HFE %), hatchability percentages of total eggs (HTE %), late embryonic mortality (LEM %), total embryonic mortality (TEM %), total egg loss (TEL %), mortality rate (MR %) and survival rate (SR %) through three generations. BB hens and WW hens which were mated with BB toms had significantly highest averages for most of the hatch studied traits throughout generations, but no significant differences among genotypes for early embryonic mortality (EEM%) and mid embryonic mortality (MEM%) traits were found. Generations had significant effect on HTE%, LEM%, TEM% and TEL %traits.
Repeated backcrossing for two generations improved F %, HFE%, THE%, MR%, SR% and fitness index (FI) traits compared to the first and the second generations (except heterosis H1 and average degree of heterosis ADOH% for F%) which were decreased.. In addition, values for TEL%, TEM%, LEM%, MEM%, EEM% and MR% traits were also decreased. The BB variety had the best values for all former traits compared to WW variety through generations. The values of maternal additive and direct additive effects showed that offspring of the (½Bx½W) and (¼Bx ¾W) crosses as a dam with BB toms as a sire had better performance concerning F%, HFE%, HTE%, , all embryonic mortality traits, MR%, SR% and (FI) compared to WW toms as a sire with (½Wx½B) and (¾Wx¼B) crosses as a dam.