Alleviation of water deficit stress effects on safflower (Carthamus tinctorius L.) cultivars by seed priming

In order to evaluate the effects of seed priming to reduce water deficit stress in safflower cultivars, an experiment was conducted as a split plot factorial based on randomized complete block design with three replications at Shahrood Agricultural Research Center in 2015. The main plot consisted of irrigation at three levels based on the evaporation from class A evaporation pan: non water deficit stress (60 mm evaporation), mild water deficit stress (120 mm evaporation) and severe water deficit stress (180 mm evaporation) and subplots consisted of two factors include safflower cultivars (Goldasht, Sina and Soffeh) and seed priming (Primed seeds with salicylic acid and non-primed). The results showed that severe water stress reduced the grain yield by about 29 percent compared to non stress conditions. In these conditions activity of superoxide dismutase, peroxidase, ascorbate peroxidase and catalase enzymes was increased by about 33, 25, 29 and 40 percent respectively. In severe water deficit conditions, content of malondialdehyde, proline and carotenoid significantly increased but the amount of chlorophyll was reduced. Priming of seeds with salicylic acid caused the antioxidant defense system activity to be increased by about 7-9 percent, therefore increased resistance of safflower plants to water stress and resulted in greater seed yield under water stress conditions. Interaction of irrigation and cultivar appeared to be significant on seed yield and activity of catalase, peroxidase and ascorbate peroxidase enzymes.