Test cross performance and combining ability studies of elite maizE (Zea mays L.) Inbred lines in the central rift valley of Ethiopia

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