Twenty four common wheat varieties were used to establish the experimental materials for the two biometrical tools used in this concern i.e., triple test cross analysis and six populations analysis.
Mean values of backcrosses to F1's (L3i) showed increased in mean values and surpassed the other backcrosses for all traits studied, showing highly grain yield / plant and other yield contributed traits. It is clear that the backcrosses to L2 (Sids 12) tended to decreased in mean values for most traits showing low grain yield / plant with other yield attributes. On the other side, mean values of hybrids (L1, L2 and L3) surpassed lines in most traits indicating some sort of hybrid vigour. The means of lines and testers differed significantly from each other. The mean square for deviations L1i + L2i – 2L3i revealed presence of highly significant over all epistasis for all traits studied. The data revealed highly significant mean squares due to sums (L1i + L2i) for all traits studied. However mean square due to differences (L1 i- L2i) were significant only for 1000 grain weight, heading date, main culm spike length, number of spikelets / main culm spike, number of spikes / plant and plant height. The highest proportion of recombinants that possible outperform parental range was obtained for number of grains / spikelets followed by main culm spike length and main spike yield. These results reflecting fair amount of genetic variability and considered valuable further breeding studies aiming to improve such chatacters. Significant positive between epistasis gene effects controlling main spike yield and number of grain / main culm spike, and between number of grain / spikelets with number of spikes / plant. The main spike yield, main culm spike length, number of grains / main culm spike and number of spikeletes / main culm spike had a strong relation with grain yield.
Dominance gene effects (d) were found to be significant in the four crosses for number of spikelets/main culm spike under 35kg.n./f only. The three epistatic types were found to be significant for most traits under investigation. High heritability estimates in broad sense were detected for nearly all traits studied. High estimates of narrow sense heritability were found for all crosses for heading date, plant height, number of spikes per plant, main culm spike length, number of kernels per spikelets, number of kernels per main culm spike and grain yield per plant under 35 kg.n./f. High genetic advance under selection was found to be associated with high narrow sense heritability estimates for number of spikes per plant and grain yield per plant for all crosses under 35 kg.n./f. for all crosses, number of kernels per spikelets under 35 kg.n./f. for third and fourth crosses.