Seed performance is one of the key points for high productivity in crop development. The objective of this study was to evaluate the physiological potential of popcorn cultivar seeds (IAC 125 and BRS-Ângela) treated with Stimulate® bioregulator under water stress. Popcorn seeds were submitted to different osmotic potential levels 0; -0.1; -0.3; -0.6 and -0.9 MPa and induced by mannitol, after being treated with bioregulator at the dose of 1.5 L 100 kg-1 of seeds. The experiment was conducted in a completely randomized design, in a 5 × 2 × 2 factorial design (osmotic potential levels x cultivars x absence and presence of bioregulator). The variables evaluated were: first count and final count of germination standard, shoot length, primary root length, and dry biomass of seedlings. Treating popcorn seeds with bioregulator is inefficient in improving the physiological potential under normal conditions and little water restriction, but under conditions in which water may be limited, the use of bioregulator positively influences germination, growth, and initial performance of seedlings.