Effects of Application of Biostimulant and Potassium Nanofertilizer on Yield and Physiological Traits of Quinoa ( Chenopodium quinoa Willd) Under Drought Stress

The present study reports on an investigation into the effects of applying biostimulants and potassium nanofertilizer on yield and physiological traits of quinoa grains grown under drought stress. Split-factorial experiments were conducted in a randomized complete block design with three replications during 2017-2018 and 2018-2019 in Tehran, Iran. Normal irrigation (50% filed capacity) as control along with three levels of drought stress (-0.3,-0.6, and-0.9 MPa) were considered as the main factor and biostimulants (a combination of nitrogen-fixing bacteria and mycorrhiza fungi (non-application, 1, 2, and 3 g kg(-1 )) and potassium nanofertilizer (non-application and application) were the sub-factors of the study. Findings suggested that under 50% filed capacity and application of biostimulant (3 g kg(-1) ) maximum biological yield and grain yield (8926 and 2809 kg ha(-1) , respectively) was obtained With increasing stress level, the mean calcium and magnesium contents of the grains decreased (2.73% and 2.40%, respectively) in 50% filed capacity drought to 1.45% and 1.42%, respectively in severe stress drought condition. While drought stress decreased seed oil, the application of biostimulant and potassium nanofertilizer improved this trait by 34.67% and 27.90%, respectively. In sum, the application of biostimulant and potassium nanofertilizer improved the growth of quinoa under drought stress.