Abstract
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.
Keywords: grain yield, harvest index, proline, seed oil, total chlorophyll, zinc