Abstract:
Maize (Zea mays L.) is one of the cereals that provide calorie requirements in the traditional
Ethiopian diet. Nevertheless, productivity in farmer’s condition is far below attainable
productivity. Eighty crosses (40 inbred lines and two testers) along with four different checks
were evaluated in alpha lattice design at five locations, Melkasa, Ziway, Wolenchiti, Dhera
and Mieso. The objectives of this study were to evaluate the top cross performances of hybrids
generated using line-by-tester mating design, to identify inbred lines with good general
combining ability effects for further use in hybrid maize breeding program and to classify
maize inbred lines into different heterotic groups. Data were recorded on grain yield and 11
yield-related traits and analysis of variances were made on grain yield and other 11
agronomic traits. Combined analysis of variance revealed highly significant mean squares
due to genotypes for number of rows per ear. Mean squares due to crosses were highly
significant (p<0.01) for grain yield at Wolenchiti and Mieso and significant at Melkasa, Ziway
and Dhera. Highly significant mean squares due to line GCA were found from Ziway, Wolenchiti
and Mieso and significant from Melkasa for grain yield but non significant from Dhera. Also
highly significant mean squares due to SCA were found for grain yield at Mieso significant at
Dhera but non significant at Melkasa, Ziway and Wolenchiti. At Dhera and Mieso both GCA and
SCA were significant indicating importances of both additive and non-additive gene action in
inheritance of grain yield based on testing locations. The lines L17, L30, L1 and L2 at Melkasa;
L12, L4, L31 and L19 at Ziway; L1, L21, L25, L9 and L31 at Wolenchiti; L15 at Mieso were
the top general combiners for grain yield, respectively. Highly significant (p<0.01) SCA
effects were found from cross L22 x T2 and significant (p<0.05) SCA were found from crosses
L8 x T1, L9 x T1, and L19 x T1 at Mieso. Lines with positive and significant GCA effects for
grain yield are generally considered to have good general combining ability. such lines with
good GCA are good parents for variety development and could be included in across location
for further investigation of grain yield and related traits
