Genetic Variability of Maize (Zea mays L.) for Yield and Some Vegetative Traits Under Drought at Different Growth Stages

Abstract

This investigation was conducted at two locations, the Demonstration Farm, Faculty of Agriculture, University of Khartoum, at Shambat, and the Gezira Research Station Farm, at Medani, in one season (2003/2004). The objective was to determine the genetic variability for yield and vegetative traits of 15 maize genotypes under drought at different growth stages. The layout of the experiment was a split plot design with three replicates. Phenotypic and genotypic variances, phenotypic and genotypic coefficient of variation, heritability, genetic advance, phenotypic correlation coefficient between 19 traits, and phenotypic correlation between the drought tolerance parameters were estimated. Significant differences among genotypes were found for all traits, except days to 95% anthesis, stem diameter (45 days), leaf area index (30 and 60 days) and number of leaves/plant (45 days). Significant differences among water treatments were found for days to 25% silking, plant height and grain yield (kg/ha) at Medani. High genotypic coefficient of variation, heritability and genetic advance were exhibited by plant height. Grain yield was significantly and positively associated, at the phenotypic level, with plant height and stem diameter at 45 days, leaf area index and number of leaves/plant at 60 days. However, significantly and negatively association with days to (50% and 95%) silking was observed. The genotypes that possess drought tolerance were PR-2 under stress at vegetative stage, Z-2 under stress at reproductive stage and M-45 at both vegetative and reproductive stages.