Effect of planting date on phenological and morphological traits of new hybrids of sunflower in the temperate regions of Kermanshah

Sunflower (Helianthus annus L.) is the fourth most important oil crop in the world and Sunflower oil has high quality because of its high content of unsaturated fatty acids. In order to study the sunflower for second cropping and the effect of planting dates on phenological and morphological traits of new hybrids of sunflower a split plot experiment based on a randomized complete block design with 3 replications was carried out at the Islamabad Research Station, Iran in 2010. Three planting dates, 10th of June, 26th of June and 11th of July were main plots and sunflower hybrids, CMS 19×R43 (Azargol), Allstar, SHF-81-85 (Farokh), and SHF-81-90, were used as sub-plots. Effect of planting date on days to star-like stage, days to complete flowering, days to physiological maturity, GDD at all phenological stages, head diameter, plant height, thousand seed weight, seed yield were significantly different (P<0.01, P<0.05) Planting on 10th of June and 11th of July produced the highest (4244.7 kg ha-1) and lowest (2978 kg ha-1) yield,respectively. The results showed that the cultivars CMS 19×R43 and SHF-81-90 should be used for planting before early July and, the cultivates All star and SHF-81-85 for planting after early July.