his work aimed at evaluating twenty to crosses resulting from the cross between ten new inbred
lines and two testers of maize under two nitrogen levels (80 and 120 kg N/ feddan). The obtained twenty top
crosses along with two check hybrids (S.C. 128 and S.C. 30 k8) were evaluated under two nitrogen levels in
Randomized Complete Block design with three replications. Data recorded on days to 50% silking, plant height,
No. of row ear , No. of kernel row 100 kernel weight and grain yield plant . General and specific combining1 1 1
ability and heterosis were estimated for studied traits. Significant mean squares due to nitrogen fertilization were
detected for all traits. Also, significant mean squares due to crosses and their partition as well as their
interaction with nitrogen levels were detected for all studied traits. The top cross M34 x M8 expressed the best
mean value for number of kernels row , weight of 100 kernel and grain yield plant . Mean squares due to SCA1 1
were more important than those of GCA for all traits revealing the important role on non-additive gene action
in controlling these traits. The line M25 seemed to be the best general combiner for days to 50% silking. Parent
M 30 seemed to be the best general combiner for grain yield plant . The most desirable SCA effects for grain1
yield were detected for the crosses CLM 343x M8 at N1 level and M7x CIMMYT 14 at N2 level and combined
data. The best heterotic effects for grain yield plant were detected for the cross M34x M8 relative to both1
checks under all environments. Factor analysis divided the studied variables into three factors which accounted
for 70.31 of the variance structure. The first factor included five variables and accounted for 29.74%. The second
factor included four variables and accounted for 24.88% of the total variance. The third factor included only
one variable and accounted for 15.69%. |
