This experiment was carried out in two fields in two areas in 2010. One of the fields was located at Neka town with 5 meter s above sea level and other one was at sari city with 905 meters above sea level. Weeds treatment (control and without control) was chosen as main factor and nitrogen treatment (0, 23, 46, 69, 92 kg h-1) as sub-factor. Results showed that bending moment 3rd and 4th inter-nodes at Neka town area (15.56 and 8.74 %) was more than sari city area respectively. With weeds control increased grain yield (40.73 %) because of less inter-specific competition and increase panicle length. Maximum grain yield was obtained for nitrogen treatment (69 and 92 kg h-1) because of increase in panicle length. Bending moment 3rd and 4th inter-nodes (28.32 and 22.61 %) increased in nitrogen treatment (92 kg h-1) over control because of increase in plant height, stem length, 3rd and 4th inter-nodes length and 3rd and 4th inter-nodes diameter. Minimum and maximum height, number and weeds dry weight were for control and nitrogen treatment (92 kg h-1) respectively. Weeds control treatment and nitrogen treatments (69 and 92 kg h-1) were best treatments because of increase in grain yield.