Investigation of different planting dates effects on yield and yield components of four soybean cultivars in Miyaneh region

In order to investigation of the effect of planting date and varity on yield and some agronomic characters in soybean (Glycine max) a field study was conducted as factorial experiment as a randomized complete block design with three replications in Islamic Azad university – Miyaneh Branch. There were planting dates in three levels: 4 April, 9 May and 5 May, as factor A and cultivars in four levels: Clark, Williams, Zan, Harcor as factor B. The Results showed that planting date has a significant effect on plant height, number of pod per plant and grain yield, biological yield, Harvest index and Kerned oil content. With delaying on planting date after 4 April, height plant number of pod, plant grain yield, biological yield, harvest index, and oil context where decreased but no significant difference on thousand grain yield, number of seed in pod and protein percent effect of planting date was not significant cultivar Zan had a higher grain yield, biological yield, number of pod plant thousand grain yield and oil percent in all three planting dates but it had a lowest protein percent in comparison with other cultivars. Also the results showed that the best planting date and cultivar, is 4 Apr., and Zan C.V. with 649 kg/ha grain yield. There were positive and significant correlation coefficients between grain yield and biological yield, harvest index, oil percent, Kernel protein context, thousand grain yield and number of pods per plant at % sprobability level.