Alleviating Effects of 2,4-Epibrassinolide Priming in Seed Germination of Proso Millet Under Drought Stress

Drought stress is a major factor limiting seed germination and seedling establishment in crops. Here, two proso millet (Panicum miliaceum L.) varieties were used to evaluate the effects of 2,4-epibrassinolide (EBR) seed priming on germination under polyethylene glycol (PEG)-simulated drought stress. Seeds primed with different EBR concentrations were assessed for germination traits, seedling growth, water absorption, and α-amylase activity. Drought stress markedly reduced germination potential, germination rate, germination index, and vigor index, while prolonging mean germination time. EBR priming alleviated these adverse effects, with 0.01 µmol·L−1 showing the most consistent and effective promotion of germination and early seedling vigor under drought conditions. The two varieties exhibited different response patterns to EBR, indicating genotype-dependent sensiortivity. Moreover, EBR priming enhanced seed water uptake and maintained higher α-amylase activity, suggesting improved reserve mobilization and energy supply during germination. In conclusion, optimal EBR priming effectively mitigates drought-induced inhibition of proso millet germination and provides a useful strategy for improving seedling establishment under water-limited conditions.