Effect of nitrogenous and phosphorus biofertilizers on seed germination and some biochemical characteristics of two quinoa cultivars (Chenopodium quinoa Willd) under drought stress

The present study was performed to investigate the effects of nitrogen and phosphorus biofertilizers on seed germination, growth, and some biochemical indices of quinoa seedlings (Sajama and Titicaca cultivars) under drought stress. Therefore, a three-factor factorial experiment was conducted in a completely randomized design with three replications in 2019. The experimental treatments were two cultivars of Sajama and Titicaca as the first factor, four levels of drought stress (control, -0.4, -0.8, and -1.2 MPa) as the second factor, and four levels of nitrogen and phosphorus biofertilizers (control, nitroxin, biophosphorus, and a combination of nitroxin and biophosphorus) as the third factor. Experimental results showed that all measured biochemical characteristics, such as proline content, soluble sugar content, and malondialdehyde content, increased significantly in severe drought stress (drought level of -1.2 MPa) compared to other drought levels for both quinoa cultivars. On the other hand, the germination percentage, germination rate, seedling length, and dry weight of seedling indices had decreased under the application of drought stress. The values of germination rate, seedling length, and seedling dry weight indices had decreased equal to 33, 46, and 51% in the application of severe drought stress than the control treatment for Sajama cultivar and equal to 16, 42, and 39% for Titicaca cultivar, respectively. Further, simultaneous inoculation of seeds with nitroxin and biophosphorus fertilizers was reduced the effects of drought stress on the studied traits in both cultivars compared to no application of biofertilizers.