effect of plant density and nitrogen on yield and yield components of maize var. 704

the objective of this study was to evaluate the effect of plant population and nitrogen rate on yield and yield components of corn (zea mays l, hybrid 704) in 2008 at mamasani region, fars province. the experiment was conducted as a factorial based on randomized complete block design with three replications. experimental factors was four plant population (75000, 90000,105000, and 130000 plant ha-1) and three nitrogen rates (200, 300 and 400 kg ha-1). results indicated that plant density, nitrogen and interaction between plant density and nitrogen had significant effects on 1000 grain weight. by increasing plant density, 1000 grain weight significantly decreased from 290 to 269 gr, and with increasing nitrogen rate from 200 to 400 kg ha-1, 1000 grain weight significantly increased from 269 to 287 gr. associated with the interaction of plant density and nitrogen on grain weight, the highest 1000 grain weight was at density of 75000 plant ha-1 with consumption of 400 kg n ha-1 and the lowest was at density of 130000 plant ha-1 withconsumption of 200 kg n ha-1. by increasing plant density, number of seeds per ear significantly decreased from 584 to 491 and number of ear per m2 significantly increased from 7.4 to 12.9. grain yield was significantly increased from 12910 to 16890 kg ha-1 by increasing plant population from 75000 to 130000 plant ha-1. nitrogen rates and its interaction by plant population had no significant effect on number of seeds per ear, number of ear per m2 and grain yield. in summary, density of 130000 plants per hectare with consumption of 200 kg nitrogen per hectare will be introduced as the most appropriate treatment.