Interaction deficit irrigation operations and nitrogen rates on the quantitative yield and oil percentage of sunflower Sanbura cultivar (Helianthus annuus L.)

In order to investigate the impact of deficit irrigation operations and nitrogen rates on quantitative yield and oil percentage of sunflower Sanbura cultivar an experiment was carried out at Shahid Salemi research farm in Ahvaz in 2012-13 cropping year. The present research was conducted as split plot experiment with a randomized complete blocks design with three replications. The deficit irrigation treatment as the main plot was applied at three levels complete irrigation, irrigation stop only at the stage R3 and irrigation stop only at the stage R5 (. Nitrogen rates was applied as the sub-plot at three levels of 50, 100 and 150 kilogram pure nitrogen per hectare. The variance analysis results showed that deficit irrigation operations had a significant effect on number of seeds per head, grain yield, one-thousand seed weight, kernel to whole grain percentage ratio and harvest index. Also, the effect of nitrogen rates on number of seeds per head, grain yield, one-thousand seed weight, oil percentage, kernel to whole grain percentage and harvest index was significant. The interaction deficit irrigation and nitrogen had a significant effect on number of seed per head, grain yield, one-thousand seed weight and harvest index. In the interaction of treatments, full irrigation and the amount of 150 kilogram pure nitrogen per hectare with 322 gram per square meter produced the highest grain yield. As a result, it can be said that the operation of deficit irrigation in the R3 and R5 stages (plant reproductive stages), due to the significant yield reduction, is not desirable.