The present work was carried out at Etay-Elbaroud Agriculture Research Station Behera governorate during four seasons from 2007/ 2008 to 2010/2011. Three crosses were made among four parents, namely Gemmiza 9 × Irena, Sids 1× Sakha 93 and Sids 1× Irena. Five populations (P1, P2, F1, F2 and bulk of F3) for each cross were used in this investigation. Highly Significant positive heterotic effect was found in the 2nd cross for grain yield and its attributes i.e., number of spikes/plant, number of kernels/spike and 1000-kernel weight and grain yield/plant, being 8.69%, 9.78%, 6.71% and 9.78% in the same respective order. Meanwhile, Negative significant heterotic effects were obtained in the 3rd cross for both number of spikes/plant (-17.45%) and number of kernels/spike -3.08% led to a reduction in grain yield/plant with a value being (-10.37%). Complete dominance was found for number of spikes/ plant and 100-kernel weight in the first cross whereas, overdominance (p>1) was detected for grain yield and its attributes in the 2nd cross. The other types of dominance were also found.
Inbreeding depression estimates were significant with a positive value for number of spikes/ plant in the first and third cross, number of kernels/ spike and grain yield/ plant in all crosses. On the other side, inbreeding depression was negatively significant for number of spikes/ plant in the second cross and for 100-kernel weight in the second and third cross. Additive gene effects were positive and significant for number of kernels/ spike in the second and third cross and 100-kernel weight in the first cross. Dominance gene effects were found to be significant for all studied characters with the exception of number of kernels/ spike in the first and second cross indicating that dominance played a major role in the inheritance of such characters. Significant and positive (E1) values were found for 100-kernel weight in the studied crosses. While, negative values were obtained for number of spikes/ plant in the third cross, number of kernels/ spike in all crosses, and grain yield/ plant in the second and third cross. Moreover, (E2) values were found to be positive and significant for 100-kernel weight in the third cross only. On the other hand, significant negative (E2) values were detected for number of spikes/ plant and number of kernels/ spike in the three crosses, for 100-kernel weight in the second cross, and grain yield/ plant in both the second and third cross. Narrow sense heritability estimates were ranged from 39.35% for number of spikes/ plant in the third cross to 94.32% for grain yield/ plant in the second one. The parent-off spring regression heritability estimates were high and ranged from 58.85% for number of spikes/ plant in the third cross to 95.65% for grain yield/ plant in the second one. The expected genetic advance (Δg) for number of spikes/ plant was ranged from 3.87 to 10.17 for the selected 5% of F2 compared with the actual genetic gain which was ranged from 5.07 to 9.37 in the studied crosses. Meanwhile, the expected gain for grain yield/plant was ranged from 21.05 to 36.26 gm.whereas, the actual gain was ranged from 18.46 to 26.81 gm.