Document Type : Original Article


Agron. Dept., Fac. Agric., Zagazig Univ., Egypt


The present study was performed to determine the extent of standard heterosis in forty five crosses resulting from a 10 × 10 diallel analysis system. The obtained crosses along with two checks (S.C. 10 and S.C. 30k8) were evaluated in two different planting dates i.e., May, 15th and June 15th. Standard heterosis were computed for days to 50% tasseling, days to 50% silking, plant height, ear height, chlorophyll content, grain yield / plant, protein (%) and oil (%) in each planting date as well as combined analyses.  Results indicated that the single cross P5 × P6 expressed the highest desirable heterotic values for days to 50% tasseling and chlorophyll content relative to both checks. The hybrid P4 × P5 gave the best standard heterotic effects for days to 50% silking relative to both checks. The best standard heterosis for plant height and ear height relative to both checks was obtained for the cross P1 × P8 in the second planting date and combined data. For grain yield/plant, the most desirable standard heterotic effects were obtained for the cross P6 × P8 relative to S.C. 10 and S.C. 30k8, recording 20.10% and 17.72% in the combined analyses, respectively. The best standard heterosis effects for protein (%) were detected in the cross P4 × P7 relative to both checks in the second planting date and the combined analyses. For oil (%), the best heterosis values relative to both checks were detected for the cross P1 × P2 in the combined analyses. The correlation coefficient values between grain yield/plant and each of chlorophyll content, ear length, ear diameter, number of rows/ear, number of grains/row, 100 grain weight and shelling (%) were positive and highly significant. The factor analysis technique divided the studied variables into four main factors accounted for 77.83% of the total variance. The first factor included four variables i.e., ear length, number of rows/ear, number of grains/row and shelling (%) and accounted for 21.15%. While, the second factor consisted of two variables i.e., plant and ear heights and accounted for 19.73% of the total variance. The third factor included two variables namely, days to 50% tasseling and silking and accounted for 19.00% of total variance. Three variables were loaded in the fourth factor i.e., chlorophyll content, ear diameter and 100 grain weight and accounted for 17.95% of the total variance of the dependence structure.