Genetic variability, stability, and differential responses of maize genotypes to drought and salt stresses during germination

This study investigated the genetic variability, stability, and adaptability of 25 maize genotypes under drought and salinity stresses during germination. The experiment applied four iso-osmotic treatments: control, two levels of polyethylene glycol (PEG) to simulate drought (20% and 22%), and sodium chloride (NaCl) at 200 mM to simulate salinity stress. Six seedling traits were measured, including shoot and root lengths, and fresh and dry weights. Statistical analyses revealed significant genotype-by-environment (G × E) interactions for most traits. Heritability estimates were low, ranging from 2.19% to 10.63%. AMMI analysis showed that the first principal component accounted for 56.3% to 90.5% of the G × E variance. GGE biplot analysis clearly separated the salinity environment from drought conditions. Correlation analysis showed weak or negative relationships between genotype performance under salt and drought stresses, confirming different tolerance pathways. Using multi-trait WAASBY integration, genotypes G19 and G14 were identified as broadly stable and high-performing across stresses, while G21 and G10 exhibited exceptional stability for shoot and root length traits. Genotypes G15 and G22 were specifically adapted to drought, while G3, G11, and G13 performed best under salinity stress. These findings provide valuable insights for breeding maize varieties with improved tolerance to drought and salinity during germination.