عنوان مقاله [English]
Effects of sowing date and water deficit were studied at different reproductive growth stages on some qualitative and quantitative characteristics of sunflower cv. Azargol in Sistan, Iran. The experiment was carried out using a split plot experiment based on a completely randomized block design with three replications at the Research Station of Zahak in 2010. There were three levels of sowing times (2010/03/15, 2010/03/24, 2010/04/04) as main-plots, and irrigation levels (normal irrigation, water withhold at budding stage, 50% in flowering and grain filling stages) as sub-plots. The interaction between planting date and water withhold on all traits were not significant. The effect of water withholding different growth stages on grain yield, oil content, grain number, grain weight, were statistically significant at the 1% probability level. No significant difference was observed among treatments in water withhold and oil yield. The effect of planting date on head diameter, grain number and grain weight was significant at 5% level so that the lowest value measurement of head diameter, grain number and grain weight was the third planting date. Withholding irrigation had a negative impact on grain yield and oil percentage. According to the result of the research, 15 and 24 March would be recommended as proper planting date in this region.