The effects of tillage system and plant density on yield and yield components of corn (Zea mays L.) varieties in north of Iran

In order to investigate the effect of tillage system and plant density on grain yield component in three varieties of corn، an experimental design was a split factorial based on RCBD treatments arrangement with four replication in north of Iran in 2009. Tillage system was selected as the main plot in three levels، conventional tillage (CT)، minimum tillage (MT) and no tillage (NT). Other factors were plant density in three levels (65، 75and 85 plant/ha) and three varieties of corn (L. cv. sc 500، L. cv. sc 540 and L. cv. dc 370). The results indicated that different tillage systems on root dry weight at harvest، seed length were significant (p<0. 05) but plant density on number grain in row، root dry weight، stem diameter، grain yield in the 1% level were significant (p<0. 01). Also plant density on high plant was significant (p<0. 05). Effect of varieties on grain yield was significant (p<0. 05). Maximum grain yield 6. 41 t/ha in SC540 and at least grain yield 3. 53 t/ha in DC 370 were obtained.