Two experiments were carried out using two crosses namely Giza 168 x
Gemmeiza 7 and lrina x Sids 1. Five populations (P1, P2, F1, F2 and F3) for each
cross were used in this investigation.
Significant positive heterotic effects were obtained for number of spikesfplant
and grain yieldipiant in the first cross. On the other hand, significant negative
heterotic effects were found for number of kernelsfspike, number of spikes per plant
and grain yield per plant in the second cross Over dominance towards the higher
parent for number, of kernelsfspike and grain yield per plant observed in the first
cross. inbreeding depression estimates were found to be significant for all studied
attributes except for number of spikesfplant and grain yieldfplant in the first cross. On
the other side inbreeding depression were significant negative for kernel weight in the
second cross. F2 deviation (E1) were significant for all studied characters for two
crosses except for number of spikeslplant and grain yieldfplant in the first cross.
Moreover, F3 deviation (E2) were significant for all studied characters in two crosses
except for grain yieldfplant in the first cross.
The (additive — additive x dominance) gene effect was significant for all
studied characters in two crosses. These results suggest the potential for obtaining
further improvement in most studied characters. in addition, dominance and epistasis
were found to be significant for most of the studIed attributes.
High to medium values of heritability estimates were found to be associated
with high and moderate expected and actual grain in most characters. This obtained
results indicated that selection for the studied characters could be used in the early
generations but may more effective if post poned to late one.
These study concluded that it may be take in considration the first cross
(Giza 168 x Gm. 9) to improve the breeding program in the national wheat research
program.