Assessment of Genetic Parameters and Multi-trait Selection for Morpho-physiological Characteristics in Drought-tolerant Maize

Abstract

Background: Drought tolerance in maize is essential for stabilizing yields amid increasingly erratic rainfall patterns. This study aimed to estimate the heritability of agronomic and morpho-physiological traits, predict genetic gain under water stress and identify top-performing hybrids across varying drought intensities. Methods: The study evaluated 35 maize hybrids under drought at ICERI (Inceptisol) using an RCBD with three replications, applying 350 kg/ha NPK + 150 kg/ha urea at 10 DAP and 200 kg/ha urea at 30 DAP, with drought imposed by withholding irrigation from 40 to 80 DAP (CIMMYT protocol). 15 traits were measured and ANOVA, genotypic/phenotypic variance, broad-sense heritability, genetic advance and MGIDI index. Result: ANOVA revealed significant genotypic differences (p less than 0.05) for all traits, with leaf area (h2=0.60), SPAD (h2=0.57) and grain yield (h2=0.57) showing high heritability and genetic advance (GA% up to 49.6%). Grain yield correlated strongly positively with ear length (r=0.74), kernels/row (r=0.72) and 1000 kernel weight (r=0.61), but negatively with leaf angle (r=-0.34) and days to tasseling (r=-0.37). The MGIDI identified genotypes Gen 30, Gen 12 and Gen 6 with balanced drought performance.