Unraveling Effect of Seed Priming with Phytohormones and Polyamines in Alleviating Drought Stress in Maize: Its Impacts on Growth, Physiology and Yield at Seedling and Reproductive Phase

Climate change significantly challenges maize (Zea mays (L.)) production, with drought stress critically hindering crop growth and yields, especially during seedling and reproductive stages. Therefore, the present study investigates the mitigation of drought stress in maize COH(M) 8 for sustaining production through seed priming with phytohormones and polyamines viz., melatonin, serotonin, spermine, spermidine, salicylic acid, and brassinolides under simulated drought conditions in in vitro and in vivo experiments. In vitro screening used simulated drought stress condition of -0.4 MPa PEG 6000, to assess impact of seed priming treatments on morphological, physiological and biochemical traits. Results from in vitro experiment showed that, melatonin, 150 µM proved to be most effective priming agent in enhancing seed germination and vigor compared to non-primed seeds under simulated drought condition. These findings were validated under field conditions especially during the reproductive stage, where primed plants showed significant differences in plant height, flowering, pollen morphology, physiological, biochemical and yield determinants compared to non-primed seeds under drought stress. Notably, seeds primed with melatonin 150 µM exhibited enhanced antioxidant activity, higher relative water content (41 to 75%), increased proline levels (177—159 mg/g) and reduced malondialdehyde (0.84—0.74µmolg−1) contributing to improved cellular homeostasis and drought tolerance. These adaptive responses minimized yield reduction under stress, with melatonin-primed seeds recording higher plot yields (32.18%) suggesting its potential for further evaluation across multiple locations, to determine stability in yield and drought resistance. This study highlights the efficacy of seed priming with phytohormones as a promising strategy for improving drought resilience in maize.