Genetic analysis of resistance to northern leaf blight of tropical maize inbred lines

Forty-five single cross hybrids generated through 10 x 10 half diallel crosses, parents and two checks were evaluated across five NLB infested locations in 2 years using a 5 x 11 alpha lattice design to understand the combining ability and heterosis among the 10 parents, diversity amongst the hybrids, relationship between yield and some yield-related traits, and, G x E interaction across test locations. Analysis of variance showed significance for locations and year for traits of study except ear rot (ER) and moisture content (MC). Only 50% silk emergence does not showed significant for genotype and Genotype x Location interaction (G x L). Negative mid-parent heterosis for grain yield suggests the importance of dominance gene in the inheritance of grain yield under NLB disease infection. Low positive correlation revealed between inbred and hybrid grain yield suggests the possibility of high level of inbreeding. Significant negative relationship expressed between NLB severity score and other traits across test locations indicates the unpredictability of NLB disease in different locations since the development and severity of the disease is weather dependent.