Assessment of Genetic Variability, Heritability and Genetic Advance for Yield Attributing Traits of Maize (Zea mays) Genotypes

Maize ranks second after rice in terms of area and production in Nepal. Maize is a cross-pollinated, C4 type crop that is highly responsive to fertilization, resulting in high daily productivity. Maize genetic diversity offers a better opportunity to plant breeders for improvement through selection. The aim of this study was to determine the genetic variability, heritability and genetic advance of several maize genotypes, along with correlation, and direct and indirect effects of various traits. The experimental site has a warm tropical climate. The experiment was conducted in a Randomized Complete Block Design with 3 replications and 9 treatments, respectively. All maize genotypes were obtained from the Prime Minister Agricultural Modernization Project, Dang, Nepal. Analysis of variance showed substantial differences for almost all traits under study. Grain yield (34.97%, 37.12%) and ear height (31.33%, 37.99%) had the highest genotypic coefficient of variation and phenotypic coefficient of variation. A high value of heritability was recorded for grain yield. Grain yield had the highest genetic advance as a percent of the mean (67.87%), followed by ear height (53.19%). Grain yield showed positive and significant phenotypic correlation with all traits except days to 50% tasseling, ear diameter and number of rows per ear. Path analysis revealed that traits like test weight, weight of kernel per ear and ear height had the most favorable impacts on yield, both directly and indirectly. The study showed that the selection of any of these traits would lead to an improvement in grain yield.