Comparative Genetic Evaluation of Maize Inbred Lines at Seedling and Maturity Stages Under Drought Stress

A shortage of water acutely restricts maize plant development, which ultimately limits maize production. The identification of the potential genotypes under drought stress is essential for genetic modifications. Here, we used two-step screening, seedling and maturity stages, to confirm the potential drought-tolerant maize germplasm and provide a more concise basis for potentially effective drought-tolerant indicator traits. We evaluated inbred lines in a completely randomized design with factorial arrangements under greenhouse conditions at both developmental stages. Three levels of irrigations were applied (normal, 50% irrigation, 25% irrigation). The results indicated that inbred lines A-521-1, M-14, A-239, and OH-8 performed better than other inbred lines at both developmental stages under drought stress conditions. Seedling-stage traits such as fresh root weight, fresh shoot weight, dry root weight, dry shoot weight, and root density exhibited maximum heritability, while root length, shoot length, and chlorophyll content offered the highest genetic advance. Maturity-stage traits including grain yield per plant, leaf area, and plant height offered higher genetic advance, while cob diameter, plant height, and grain rows per cob indicated maximum optimistic influence on grain yield. Our results suggested that selection based on these traits can be beneficial for the identification of better germplasms under drought conditions. Overall, our results confirmed that comprehensive phenotyping at the seedling stage is an efficient way for rapid selection of drought-tolerant germplasm and this selection promotes yield stability at maturity stage. The best-performing inbred lines under drought stress conditions can be useful in future maize breeding programs.