Hybrid Performance, Heritability and Trait Associations in Yellow Maize (Zea mays L) Inbred Lines

Abstract

The challenge of decreasing maize yields in Kenya and Sub-Saharan Africa due to biotic and abiotic stresses is further compounded by limited supply of improved hybrid varieties. This study aimed to evaluate the hybrid performance, heritability and examine phenotypic correlations between grain yield and yield-related traits in yellow maize inbred lines in Western Kenya. One hundred and thirty F1 testcrosses produced using a line-by-tester mating design of two-line testers on 65 yellow lines were evaluated across three locations using a 7×19 alpha lattice with two replications. Phenotypic data on grain yield and yield related traits were used to compute best linear unbiased estimates of means and variance components in META-R while R package ‘corrplot’ computed phenotypic correlations.  Significant (p=0.001) genotypic and genotype-by-environment variances were observed for grain yield and related traits, except for plant height which did not show significant genotypic variance. With a trial mean of 9T/Ha and an LSD0.05 1.7, the testcross L45×TA produced the highest grain yield across sites at 12.4T/Ha. Studied traits showed high heritability across sites, with the exception of the Northern leaf blight, which had moderate heritability (46%). Significant phenotypic correlations were found between traits, with ear height showing the highest positive correlation with grain yield (r = 0.67, p=0.001).  With higher genotypic variance than genotype-by-environment interaction variance, high heritability for grain yield and related traits and significant correlations between them, this germplasm offers opportunities for both direct and indirect selection in maize breeding programs aimed at yield improvement since most of the measured traits are largely dependent on the genetic value of the germplasm.