In 45 Fs and 10 parents of wheat were used to estimate some genetic
variability for main spike characters. The parents were: Gemmeiza1. Gemmeiza3,
Sakha 69, Sids 1, Giza 165, Sakha 8, Giza 163, Giza 162, Sakha 92 and Giza 164.
The 45 F5 genotypes were introduced through dialiel crosses mating design10x10.
The studied characters were, heading date, spike length, number of grains/spike,
1000-grain weight and grain weighVspike. This investigation was conducted at Tag EI-
Ezz Research Station Oakahlia Governorate dunng 2000/2001 and 2001/2002
growing seasons. The results indicated that the cross Gemmeiza1x Giza 163 show
earliness. longest of spike and highest of 1000-grain weigh while cross (Sids1xGiza
164) was the highest for number of grains/spike and grain weighVspike. Phenotypic
and genotypic variances showed highest estimates concerning of all studied
characters. Estimates of phenotypic and genetic advance indicated high values for
heading date 1000 grain weight and grain weighVspike. Heritability in broad sense
was high for these characters; it was 95.29% for heading date, 94.56% for 1000-grain
weight and 94.31 % for grain weighVspike. The phenotypic correlation coefficients
cleared that there was highly significant and positive correlation between grain
weighVspike and remaining characters, except 1000-grain weight whereas it was
highly significant and negatively between 1000-grain weight and both spike length and
number of grains/spike.