Response of yield related traits in three grain corn hybrids to weed competition periods

In order to investigate the response of yield related traits in three grain corn hybrids to weed competition periods, a factorial experiment was conducted in research station of agriculture faculty of Islamic Azad university of Tabriz based on randomized complete block design in three replicates in 007. The treatments were combination of weed interference periods (interference until –, –6, and 6–8 leaf stages of corn, full season weed interference and weed free control plot) and three corn hybrids (0, 60 and 70). Results showed that the traits such as stem height, number of grain row per maize, and grain yield were significantly influenced by corn hybrids, But by weed interference treatments. Results indicated that biological yield, dry weight of stem, leaf and maize were affected by weed interference treatments and reduced %, %, % and %, respectively in full season weed interference treatment. 0 Hybrid with stem height of 69 cm, grain yield of. 8 tha- and biological yield. 6 tha- was better than 60 and 70 hybrids. In interference treatments, weed free control plot showed the best result.