Improving agronomic and morphological characteristics of forage maize by changing planting date and determining the most suitable harvest time in Varamin region

In order to investigate the effect of planting date and harvest time on the morphological traits of forage maize (cv. Karoun 701), an experiment of split plot in randomized complete block design with three replications was conducted in Varamin in year of 2015. Treatments included five planting dates as main factor (9th of April, 21th of May, 18th of June, 30th of June and 15th of July) and two harvesting times as sub-factor (milky stage and dough stage). The result showed that the effect of planting dates had significant at 1% level on the plant height, leaf width, leaf area, cob diameter and fresh yield. But had no significant effect on the number of leaf per plant, leaf length, number of internode per plant and stem diameter and were not affected by planting date. Results of this experiment showed that planting date of 30th of June was superior to other planting dates in terms of morphological traits such as plant height, leaf width, leaf area, cob diameter and fresh yield of plant compared to other planting dates, and the amount of the above traits with early and delay in planting are greatly reduced. In between, harvesting time at milky stage had the highest leaf width and leaf area and harvesting at dough stage had the highest fresh yield of plant. It is recommended to obtain optimum corn yield, sowing operations should be carried out in the first half of July in Varamin region and for harvesting quality forage at milky stage and to obtain greater harvest yield at dough stage.