HETEROSIS AND FACTOR ANALYSIS FOR SOME IMPORTANT TRAITS IN NEW MAIZE HYBRIDS

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, 15^th and June 15^th. 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.