Integrated Assessment of Drought Tolerance Indices in Maize Genotype Selection

Drought tolerance assessment in maize requires the integration of yield performance and multiple stress-related indicators to identify genotypes combining productivity and environmental adaptation. In this study, twenty maize genotypes were evaluated under optimal and drought-stress conditions using grain yield parameters and fifteen drought tolerance indices. Significant variation was observed for yield potential (Yp), stress yield (Ys), and index-based drought responses. Productivity-related indices, including Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), Harmonic Mean (HM), Modified Stress Tolerance Index (MSTI), and Relative Efficiency Index (REI), showed strong associations with yield performance and effectively identified stable, high-performing genotypes. Correlation analysis revealed a clear separation between productivity-oriented and susceptibility-related indices. Principal Component Analysis explained 97.5% of total variation in the first two components and separated indices into productive adaptation and stress susceptibility groups. Cluster analysis classified genotypes into four distinct groups, identifying genotypes with high yield potential, superior drought adaptation, intermediate performance, and stress sensitivity. Genotypes G11, G12, and G13 demonstrated the highest yield retention under drought, while G3, G15, and G18 combined high productivity with acceptable stress performance. The integration of multi-index analysis and multivariate approaches provides an effective framework for selecting drought-resilient maize genotypes.