Three experiments were carried out at EI-Giza Agricultural Research Station
using two wheat crosses namely, Gemmeiza 7 x Sids 1 and Giza 168 x Sakha 93. Six
populations (P1, P2, F₁, Fa, BC1 and BC2) for each cross were used in this
investigation. Significant positive heterotic effects were obtained for plant height, grain
yield/plant and biological yield/plant in the first cross while, heterotic increase in
number of spikes/plant, 1 OO-kernel weight, grain yield/plant and biological yield/plant
seemed to be accounted for the heterotic response observed in the second cross. On
the other hand, significant negative heterotic effect was found for number of
grains/spike in the second one. Inbreeding depression estimates were found to be significant for all studied
attributes except for number of spikes/plant in the first cross. Over dominance towards the higher parent for 100-kernel weight, grain
yield/plant and biological yield/plant, no. of spikes/plant, were observed in both
crosses. Meanwhile, over or partial dominance towards the lower parent was obtained
for number of kernels/spike in the two crosses. On the other side partial dominance
was observed for plant height in the second one. F2 deviation (E1) were significant for number of kernels/spike in the two
crosses, and for grain yield/plant in the first cross. Moreover, backcross deviations
(E2) were significant for plant height in the first cross, number of kernels/spike, grain
and biological yield/plant in the second one. The additive gene effect was significant for all studied characters in
Gemmeiza 7 x Sids 1 cross except for number of spikes/plant. These results suggest
the potential for obtaining further improvement in most studied characters. In addition,
dominance anc epistasis were found to be significant ror some of the studied
attributes. High to medium values of heritability estimates were found to be associated
with high and moderate genetiC advance as percentage of F2 mean in most
characters. These results indicated that selection for the studied characters could be
useful in the early generations.