Pot-cultivation experiment was conducted to explore effects of middling water stress on growth, photosynthesis characteristics, active oxygen metabolism, and yield of different drought-tolerance-type maize. The correlation between the drought-tolerance of hybrids and that of their own parents was also researched. This experiment included two factors: variety and content of water in soil. Three maize hybrids and their own parents were selected in this experiment and water stress was performed in the whole li...