This investigation was undertaken at the Experimental Farm of the Faculty of Agriculture, Moshtohor, Benha
University during the two summer growing seasons of 2018 and 2019. To estimate combining ability under two
nitrogen levels and superiority% relative two check hybrids for five quantitative characters. N levels and
genotypes mean squares were significant for all studied traits. Mean squares due to genotypes x N levels were
significant obtained for all studied traits. SCA was higher than GCA for all studied traits revealing that the non-
additive effects were controlled these traits. The overall study of GCA effects suggested that parents M65, M66
and M48 were significant for general combiner for grain yield, M70 and M57 for earliness and M50 and M70 for
short plants and ear stature. However, the genotypes M65xM10, M17xM10, M37xM10 and M48xCLM550
showed high SCA effect for grain yield plant-1. The maximum heterosis was recorded by the cross M48xCLM550
in combined across nitrogen levels they out-yielded SC128 and SC2031 reached 18.00 and 14.00%, respectively.
100-grain weight were correlated significantly with grain yield with r values being 0.707** in the combined
analysis. Factor analysis for combined across N levels divided characters of maize into three factors accounted
for 78.63% of the total variability. The first factor contributed by 39.14% included ear length, ear diameter, No.
rows ear-1, No. kernels row-1, 100-kernel weight and shelling%. The second factor accounted for 24.83% and is
mainly loaded by days to 50% tasseling and silking. The third factor accounted for 14.66% is mainly described
by plant and ear heights. |
