Effect of seed treatments on germination indices of Sunflower (Helianthus annuus L.)Hybrids under drought stress conditions

In order to study the impact of different seed priming techniques under drought stress conditions on germination and early growth of two sunflower hybrids (Hysun-36 and Azargol)) an experiment was conducted at the Seed and Plant Certification and Registration Research Institute, Karaj, Iran,2011. Seed priming treatments included 500ppm Potassium Nitrate (KNO3); 1000ppm Potassium Nitrate (KNO3); distilled water (12 and 18hour) and control. Drought osmotic stress conditions prepared by using PEG6000 at different osmotic potentials (-0.3,-0.6,-0.9 MPa and control).At the equivalent osmotic potential, the negative effects of stress conditions, especially at higher concentration of PEG, was less on germination percentage and Seedling growth in Hysun-36 compare to Azargol .The more speed of germination in drought osmotic stress conditions was related to Hysun-36hybrid. Altogether Seed primed with 1000ppm KNO3 treatment had better effects than other treatments on germination attributes and seedling parameters. There were no significant differences in seeds hydro priming for18 hour compared with untreated seeds. It was concluded that increasing of hydro priming time may have negative impact on germination and seedling growth in hybrids of sunflower used in this experiment.