Effects of Foliar Application of Some Growth Regulators and Nitrogen on Growth, Yield and Oil Quality of Spring Safflower

The present study aims at evaluating the effects of leaf foliar of growth regulators and nitrogen on growth parameters and yield of spring safflower. To do so it has carried out a research at East Azerbaijan Agricultural Research Center as a factorial experiment based on RCBD (Randomized Complete Block Design) with three replications. The factors include growth regulators in four levels, namely auxin, cytokinin, auxin + cytokinin (wherein the treatment’s concentration has been 1000 mg/L), and control (no use of growth regulator, whatsoever), foliar application of nitrogen (3 and 6 per thousand), and two springcultivars (Soffe and Goldasht). Results show taller plants (17%) and greater number of heads per plant (39%), seeds per head (9%), and lateral stems (37%) for Soffeh cultivar, compared to Goldasht variety. On the other hand, Goldasht cultivar provides the maximum head diameter (15%) and 1000 seed weight (47%), in comparison to Soffeh cultivar. The maximum grain yield is observed for Soffeh cultivar with auxin growth regulator and a concentration of three per thousand foliar application of nitrogen (3205 kg ha -1),displaying no significant difference from either the control or the application of three per thousand foliar of nitrogen (3120 kg ha-1). The application of growth regulators has changed the fatty acid composition. The application of auxin + cytokinin as the growth regulator with a concentration of three and six per thousand foliar of nitrogen increase the oleic, palmitic, and linolenic acids. However, the use of auxin and cytokinin separately increase linoleic and stearic acids among the fatty acids, compared to the control, which is higher in Soffeh cultivar than Goldasht. In general, Soffeh cultivar shows higher growth and yield, compared to Goldasht cultivar, indicating the positive effect in foliar application of hormones and nitrogen for the latter.