The effect of water deficits around flowering on grain yield and plant morphology of maize in negative irrigation system

Flowering is drought sensitive, which has been used as the critical phase for drought-tolerant evaluation or screening of maize varieties. It is hard to acquire parallel plants in imprecise irrigation regimes. Hence, a negative-pressure irrigation system was introduced for accurate water control in this study. A pot experiment was performed to explore the responses of three maize hybrids – Zhengdan 958, Danyu 39, and Danyu 405 – to water deficit around flowering. Five irrigation regimes, including well-irrigated treatment (CK), ten days of moderate water deficit since 13 - leaf stage (V13M) or tasseling (VTM), and ten days of severe water deficit since 13-leaf stage (V13S) or tasseling (VTS), were applied. The small values of coefficient of variance in most observed traits demonstrated the feasibility and stability in obtaining parallel plants in the negative-pressure irrigation system. Zhengdan 958 had the least grain yield reduction (4.32 – 23.0%) after water deficits, followed by Danyu 405 (13.5 – 27.0%), and Danyu 39 (13.8 – 34.2%). The less affected kernel number in Zhengdan 958 was mainly a result of slightly decreased ear length and small ear tip-barrenness in water deficit. On the other hand, Zhengdan 958 could maintain a more stable whole plant dry matter under water deficits, benefiting from the less influenced leaf area, plant height, and stem diameter. The reported results highlight that Zhengdan 958 showed a better drought tolerance than Danyu 39 and Danyu 405, which was mainly attributed to more stable kernel number and better morphological performances under water deficits