الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
I. A total number of 23340 eggs representing 16 genotypes namely: Rhode lsland Red (R), Fayoumi (F), Dokki-4 (D4)and Dandarawi (D), R x F, F x R,R x D4’ D4 x R, R x D, D x R, x D4’ D4 x F,F x D, D x F, D4 x D and D x D4 were incubated in two successive hatches and two sucessive years during1975-1976 and 1976-1977.Every hatch indluded the eggs produced by the above-mentioned genotypes during successive 15 days. The eggs of each of the genotypes were classified according to their holding period into two groupS one week and two weeks and also classified according to their egg size into three groupS (large, medium and small). The incubation results can be summerised as follows:
1-The percentage of clear eggs increased as a holding period increased. The Fayoumi (F) eggs were less affected by holding period than those of another breeds, and the Dokki-4(D4)eggs were the most affected ones. The rhode (R)and Dandarawi (D)had the maternal effect (17.8%for each one of them ) while F and D4 had the best paternal effect (17.3% and 21.1%, respectively) of clear egg percentages.
Within each paternal or maternal group the percentage of clear eggs depend on the kind of sires and dams.
2- The F had the lowest embryonic mortality (10.5%)followed by the R (13.1%) then D (20.2%) and finally D4 (27.7%). The crossbreds had lower embryonic morta1ity than purebreds (16.3%and 17.8%, respectively).the F had the best paternal and maternal effect on embryonic motality