Effects of different irrigation levels and application of methanol and nano iron oxide on yield and grain filling components of sunflower

In order to study the effect of irrigation levels and application of methanol and nano iron oxide on yield and grain filling components of sunflower (Helianthus annuus L.), a factorial experiment was conducted based on randomized complete block design with three replications at the research farm of the Islamic Azad University, Ardabil Branch in 2017. The experimental factors were included: application of methanol (foliar application with water as control, 20 and 30 volume percent), nano iron oxide (foliar application with water as control, application of 0.3, 0.6 and 0.9 g.L-1) and irrigation levels (full irrigation as control, irrigation withholding at flowering stage, irrigation withholding at grain filling period). The results showed that the highest grain yield (2952 kg/ha), number of filled grains per head (1121 grains per head), 1000-grain weight (50 g), rate and grain filling period, effective grain filling period (0.00239 g/day, 42 and 33 days respectively) and chlorophyll index (56) were obtained in full irrigation and high levels of methanol and nano iron oxide. Maximum of proline and soluble sugars content (11.1 µg/g FW and 72 mg/g FW) were obtained in irrigation withholding at flowering stage and application of high rates of methanol and nano iron oxide. The least of they were obtained in full irrigation and no application of methanol and nano iron oxide.