Effect of planting date, drought stress and salicylic acid on yield and biochemical characteristics of quinoa

This study was conducted to investigate the response of yield and some biochemical characteristics of quinoa to planting date, drought stress and salicylic acid as split-split-plot experiment based on randomized complete block design with three replications at the experimental station of the Agricultural Faculty of Bardsir, Shahid Bahonar University of Kerman in 2018. The experimental treatments were planting date (April 5, 5 May 5 and June 5) as the main plots, irrigation levels (90, 60 and 30% of filed capacity) as subplots and foliar application (salicylic acid 1 mM and water) as sub-subplots. The results showed that grain yield for May (653.91 kg ha-1) planting date was significantly higher than April (578.7 kg ha-1) and June (460.8 kg ha-1). Decrease in consumed water to 60% of FC had no significant effect on grain yield, but the trait value in 30% of FC was significantly lower than other irrigation levels. Grain yield was significantly increased by foliar application of salicylic acid than water application only at severe drought stress. The highest oil (4.08%) and vitamin C (3.93 mg.g-1) contents were related to May planting date and non-stressed condition. Relationship of grain yield with grain antioxidant activity and carbohydrate was negative. Proline, MDA and APX values were significantly increased by drought stress, but salicylic acid could decrease the traits.Generally, the results indicated that May planting date is the most suitable planting date for quinoa in Bardsir regions and similar climates. The plant has a considerable tolerance in water stress condition based on the antioxidant defense mechanism. Salicylic acid could mitigate the negative impacts of drought stress in limited irrigation levels.