Comparative Study on Leaf Gas Exchange, Growth, Grain Yield, and Water Use Efficiency under Irrigation Regimes for Two Maize Hybrids

Abstract

Drought stress has been a great challenge for the sustainability of maize (Zea mays L.) production in arid and semi-arid regions. The utilization of drought-tolerant hybrids and proper irrigation regimes represent a management strategy to stabilize maize production under water-limited conditions. A two-year field experiment was conducted to assess the leaf gas exchange, growth, grain yield, and water use efficiency in two cultivars of maize, i.e., Zhengdan 958 (H1) and Zhongdan 909 (H2), under different water regimes, i.e., full irrigation (FI), reproductive irrigation (RI), and rainfed (RF). Plant samples were collected at different growth stages to measure the maize growth and development under the three irrigation regimes. The grain yield in RF was significantly reduced by 30.4% (H1) and 31.1% (H2); and the water use efficiency (WUE) by 8.5% (H1) and 9.3% (H2) compared with FI. On the other hand, irrigation application at the flowering stage was shown to significantly boost the grain yield by 40.3% (H1) and 25.5% (H2); and the WUE by 27.6% (H1) and 14.1% (H2) compared to RF. This indicated that H1 benefited more from irrigation use compared to H2. The improved grain yield through reproductive irrigation was due to the greater soil plant analysis development (SPAD), net photosynthesis, and biomass production when compared to zero irrigation. Zhengdan 958 was shown to be relatively more resistant to drought stress during flowering compared to Zhongdan 909. Thus, to achieve reliable maize production in Huaibei Plain, reproductive irrigation is recommended, combined with Zhengdan 958.