The effect of humic acid on some yield characteristics and leaf proline content of safflower under different irrigation regimes

In order to investigate the effect of different irrigation regimes on yield and leaf proline content of a spring Isfahan local variety of safflower, a field experiment was conducted as split plot in Randomized Complete Block Design with three replications at the Research Station of Shahrekord University in 2013-2014. The main factor consisted of four different irrigation regimes (irrigation after 50, 80, 130 and 180 mm evaporation of water from evaporation pan class A) and subplots were spraying humic acid (at a rate of zero, one, three and six liters per hectare). Evaluated traits in this experiment included, the number of heads per plant, 1000 seeds weight, oil content, grain yield, oil yield and leaf proline content. Irrigation treatments and foliar application of humic acid significantly contributed to the above characteristics. Based on means comparisons, less irrigation caused a significant decrease and spraying humic acid also increased significantly number of heads per plant, 1000 seeds weight, grain yield and oil yield. Also, with increased Irrigation and increase application of humic acid, oil content and proline compared to the control group showed a significant increase. In addition, increased irrigation, increase seed oil content from 22.22 percent to 25.43 percent (in irrigation treatment after 180 mm evaporation and application of six lit/ha) has been upgraded. Oil yield also decreased as a result of irrigation after 50 mm evaporation from 394 to 289 kg per hectare after 180 mm evaporation.