Effect of Selenium Application on Yield, Yield Components and Oil Percentage of Two Safflower (Carthamus tictorius L.) Cultivars Under Water Deficit Irrigation Conditions

The present study was performed to evaluate the effect of selenium application on yield, yield components and oil yield of safflower (Carthamus tinctorius L.) cultivars under water deficit irrigation conditions as factorial split plot based on randomized complete block design with three replications in Mahalat province, Arak, Iran during 2013-2014 crop season. The main factor included complete irrigation during growing season, cutting irrigation at flowering stage and cutting irrigation at head forming stage. Sub factor was considered application of selenium (including 0, 20 and 40 k/ha) and safflower cultivars (Sina and Mahaly Esfahan). The results showed that the plant height, leaf area, yield and yield components and oil yield of safflower cultivars decreased under water stress treatments. Discontinuation of irrigation in the pollination stage led to the greatest reduction in grain yield and oil yield by 31.6% and 39.7% compared to full irrigation, respectively. The highest grain yield, biological yield and oil yield with average of 3987, 9514 and 609 k/ha by application of 40 g/ha selenium and complete irrigation obtain, respectively. Application of selenium in discontinuation of irrigation regimes due to decrease negative effect of water stress on yield components, grain yield, biological yield and oil yield. The Mahaly Esfahan cultivar had the highest number capitulum per plant, number grain per capitulum, grain yield, biological yield and oil yield. In general, 40 g/ha application of Mahaly Esfahan safflower cultivar with selenium not only can decrease water stress effect but also increase grain yield and oil yield under optimum conditions.