Maize Hybrids Performance under Differing Irrigation Regimes: II. Grain yield, Components and Water Use Efficiency

Scarce water resources is a worldwide problem, still for Iran, a country predominated by an arid and semi-arid climate, water limitation is more severe than for many other areas of the world. A field experiment was conducted to investigate the impact of irrigation regimes on growth, grain yield and irrigation water use efficiency in maize (Zea maize L.) in 2006 at the Research Farm, College of Agriculture, Isfahan University of Technology, using a 3-replicate split-plot RCBD. Four irrigation regimes (I1, I2, I3, I4) constituted the main plots and four corn hybrids (SC 704, SC700, SC500 and TC647) served as subplots. Despite harvest index, grain and biological yield and yield components differed among hybrids and irrigation regimes. Treatment I4 produced the lowest grain (7670 kg ha-1) biological yield (16650 kg ha-1) and irrigation water use efficiency for both grain (0.98 kgm3) and biological yield (1.42 kgm3), compared to other irrigation regimes. SC700 outperformed other hybrids in terms of grain (11220 kgha-1) and biological yield (23450 kgha-1). It seems that, at least with the present study, since seed/head was more correlated to grain yield than the rest of components, knowing physiological bases of seed set variation of maize under drought stresss helps to improve grain yield under latter conditions. Furthermore, for conditions where access to irrigation water is a limiting factor, supplying the water during the more vulnerable growth stages is crucial for a more production efficiency.