Standard heterosis and trait association of maize inbred lines using line x tester mating design in Ethiopia

Maize is one of the high priority crops to feed the ever increasing population in Africa, however, its production limited by shortage of high yielding variety coupled with biotic and abiotic stresses. The study was initiated to evaluate the heterotic performances of the F1 hybrids over the standard checks (Kolba and Jibat). Fifty entries consists 48 F1 single crosses developed from 24 inbred lines and 2 testers using line x tester design and two commercial check hybrids used in the study. The experiment was conducted using alpha lattice design with two replications at Ambo and Holeta Agricultural Research Center. Analysis of variance revealed existence of significant genetic variation among genotypes for all studied traits except for plant aspect. Location x entry interaction for most of the traits was not significant which suggests hybrid performance was consistent across tested locations. The magnitude of standard heterosis over Kolba and Jibat for grain yield ranged from -40.31 (L13 x T1) to 32.44% (L23 x T1). Cross L23 x T1 exhibited maximum standard heterosis (32.44%) over Kolba and Jibat for grain yield followed by L11 x T1 (22.18%). Positive and significant genotypic, phenotypic correlation coefficient were recorded for yield with plant height (rg=48** and rp=40**), ear height, ear per plant, number of kernels per row, ears length, ear diameter and number of kernel rows per ear. Number of ears per plan (1.08) had the highest positive direct effect on grain yield followed by ear diameter (0.95), number of kernels per row and number of kernel rows per ear indicating the effectiveness of direct selection. Finally, crosses with high standard heterosis for yield and yield components could be used for developing high yielding maize hybrids in the future maize breeding program.   Key words: Heterosis, Hybrid, correlation, path analysis.