Maize hybrids with well-developed root system perform better under deficit supplemental irrigation

Water deficiency has become a major issue threatening the sustainability of arable crops globally. This study was conducted to assess the effects of deficit supplemental irrigation (DSI) at different growth phases on the performance of different maize hybrids under semi-arid climate. The irrigations were skipped either at vegetative or reproductive stage, while a sufficient supplemental irrigation was taken as control in three maize hybrids i.e., P-30Y87, S-6621 and P-30Y58. The DSI at both growth phases significantly hampered root length and proliferation, crop growth rate (CGR), leaf area index (LAI) and relative water contents (RWC). The DSI applied at both growth phases reduced the grain yield and yield related attributes, but DSI at reproductive stage was more lethal. Hybrid P-30Y87 performed better under different irrigation treatments due to better root system, crop allometry and other yield related traits compared to other hybrids while hybrid P-30Y58 recorded the lowest crop yield due to poor root system. The lateral roots had positive correlation with grains cob-1 and water use efficiency, while positive correlation among root length and grain weight and yield was observed under DSI at both growth phases. In conclusion, DSI at reproductive stage severely hampers the maize productivity; however maize productivity under deficit irrigation supply can potentially be improved to some extent by using maize hybrids with better root system. The moisture deficiency at reproductive stage proved more lethal for maize productivity, while maize hybrids with better root system potentially evaded the adverse effects of moisture deficits under semi-arid climate.