Effect of Different Levels of Irrigation and Plant Density on Grain Yield and Yield Components and Water Use Efficiency in Grain Maize cv. KSC 302

To evaluate the effects of different levels of sprinkler irrigation and plant density on yield, yield components and water use efficiency of grain maize KSC 302, an experiments was carried out in field station of Seed and Plant Improvement Institute, Karaj, Iran in 2006 and 2007 growing seasons. Split-plot arrangements in randomized complete blocks design with three replications was used. Main plots were three irrigation levels: 75%, 100% and 125% ET and sub-plots were three plants densities: 80000, 90000 and 100000 plant per hectare. Results showed that increasing irrigation levels from 75% to 125% had significant effect on grain yield and yield components, however, its effect on water use efficiency was not significant. 100% ET level had the highest WUE (1.03 Kg/m3). Effect of different plant densities on grain yield, yield components, and water use efficiency was not significant. Results revealed that 125% ET level and 90000 plant density had the highest yield and yield components, and 100% ET level and 100000 plant density had the greatest WUE. Therefore, under non-limited irrigation water resources the best option is application of 12000 m3.ha-1 of irrigation water and 90000 plant density, and under limited irrigation water conditions the best option is application of 10000 m3.ha-1 of irrigation water and 100000 plant density are suitable for areas similar to Karaj conditions.