effect of nitrogen fertilizer different levels on yield and yield components of current rice cultivars in two locations: rasht and rudsar

in this research for study the effects of nitrogen fertilizer on yield and yield components of current rice cultivars was an experiment as factorial in rcbd with three replications where conducted during 2009 year in two locations (rice research institute, rasht, and rudsar, east of guilan). factors were cultivars (khazar, ali kazemi and hashemi), and nitrogen fertilizer levels (0, 30, 60, and 90 kg n/ha). results of combined analysis of data indicated that the grain yield and final biomass was significantly affected by location, cultivar and n fertilizer. khazar (3943 kg/ha) and ali-kazemi (3417 kg/ha) were showed the highest grain yield among cultivars. the highest grain yield (3980 kg/ha) was obtained from rudsar location. also, results indicated that, with increasing n fertilizer application grain yield, was increased significantly in compared with control treatment (without nitrogen fertilizer application).