Quantitative and Qualitative Responses of Quinoa to Soil Application of Growth-promoting Microorganisms Under Water Stress

Quinoa (Chenopodium quinoa Willd) is highly resistant to a wide range of environmental stresses, including drought and salinity stresses. To evaluate the effect of bio-fertilizer and drought stress on the quantitative and qualitative traits of quinoa, an experiment was conducted on Research Farm, Shahed University in 2018. The main factors included irrigation interval 7, 10, 13, 16 days and the soil application of growth-promoting microorganisms (0, 0.1, 0.2, and 0.3% concentrations during the growth period) arranged in the sub-factor. The results showed that by increasing irrigation interval period, grain yield, 1000-grain weight and chlorophyll content decreased. The highest plant height (155.7 cm), leaves area (1543.6 cm²/plant), 1000-grain weight (2.69 g), chlorophyll a content (19.7 mg g⁻¹ FW), and seed potassium content (2.03%) were observed in 0.2% bio-fertilizer application under 13-day irrigation treatment. Application of 0.3% concentration bio-fertilizer under 13 and 16-day irrigation treatments was caused the highest grain yield (2.51 and 2.47 ton ha⁻¹) which had 14.34 and 12.95% increase compared to the control treatment. The highest percentage of accumulation of nutrients in the seed, including potassium, calcium and magnesium, was observed in the treatments of 0.3% biofertilizer with irrigation at intervals of 13 and 16 days. The results suggest that drought stress adversely affects quinoa quantitative and qualitative traits, and biofertilizer can improve quinoa plant tolerance todrought stress.