Nine inbred lines of yellow maize were top crossed to the three teslers i.e L·
121, S.C.SK·52 and cornposite-Zt during the 2001season. The nine parental inbred
lines, Ihe three testers, the 27 top crosses and the two checks (S.C155 and TW.C
352) were evaluated during the 2002 season at Sakha,Sids and Nubraria locations in
a randomized complete block design with four replications. The data were recorded
for grain yield/plant (g). number of rows/ear, number of kemels/row,ear position% and
precentage of resistance to late wilt disease. Combining ability analysis was computed
via line x tester procedures proposed by Kempthorne (1957). The results could be
summarized as follows:· Significant mean squares for locations, genotypes and their interactions
were detected for all the studied traits. Significant lines (L), testers (T) and (L x T)
interaction were detected for all studied traits except (L x T) interaction for number of
kernels/row and ear position. VVhile, the interaction between (L), (T) and (L x T) with
locations were significant for grain yield/plant and resistance to late wilt disease.
Additive genetic variance (gca) was predominanting than non-additive genetic
variance (sea) in the inheritance of all traits. The non-additive genetic variance
showed obvious interaction with locations for grain yield/plant. number of rows/ear
and number of kemels/row.The parental inbred lines which showed the best desirable
gca effects were SK·7070, SK·707812, SK·7078/30 for grain yield/plant, Gm1 004 for
number of rows/ear, SK·7070 for number of kemels/row, SK·7078/30 for ear position
and SK·7017/10 for resistance to late wilt disease. On the other hand, the parental
testers that exhibited the better general combining ability were L·121 for grain
yield/plant and resistance to late wilt disease,S.C.SK·52 for number of rows/ear and
ear position and composite-21 for number of kemels/row.The desirable heterotic
effects for grain yield/plant relative to the check S.C.155 were recorded for top cross
SK·7070 x L·121 (24.65%). Whereas, the highest heterosis values relative to the
check T.W.C 352 were detected for the top crosses SK·7070 x L·121 (28.82%) and
SK· 707812 x L 121 (17.73%). These two crosses would be prospective and
recommended to be used immediately in maize breeding programs.