Effects of priming on seed germination and field emergence of safflower (Carthamus tinctorius L.)

A laboratory experiment was conducted to evaluate the effects of hydropriming (3 and 6 h) and osmopriming (3 and 6 h KNO3, and 1 h polyethylene glycol [PEG] 6000 at -0.2 MPa) on the germination of seeds from the safflower cultivar Kuseh. Hydropriming significantly improved the germination, germination rate, germination uniformity and shoot/root ratio, and decreased the time to 50% germination, compared to the control. Hydropriming for 3h and 6 h KNO3 also significantly improved most of the germination parameters, but overall, the 6 h hydropriming treatment achieved the best results and therefore, this treatment was used to evaluate the effect of priming in a field experiment with a single seed lot from each of three cultivars (Kuseh, PI and ILIII). Hydropriming resulted in higher seedling emergence and an increase in seedling emergence rate for all three cultivars, although there was a significant priming x cultivar interaction. The greatest improvement in field emergence after priming was seen in PI, which also had the lowest initial germination. Hydropriming for 6 h may be used to improve field establishment of safflower. In addition, this treatment is simple, cheap and does not need expensive chemicals and sophisticated equipment.