Investigation of the Effect of Salinity Stress on Physiological Traits and Grain Yield of Quinoa Cultivars

Quinoa is one of the salinity tolerant plants, capable of playing an important role in providing human food in the future. In order to investigate the effect of salinity stress on physiological traits and yield of quinoa cultivars, a two-factor factorial experiment was conducted as random complete block design with three replications in 2020 year under greenhouse conditions. Experimental treatments include three quinoa cultivars (Titicaca, Q26, and Giza1) and three salinity levels (0, 15, and30 dS/m). Salinity stress reduced traits such as photosynthetic pigments, relative leaf water content, and grain yield. The chlorophyll a and b content in control conditions, compared to the salinity level of 30 dS/m, have decreased by 46% and 77%, respectively, with the yield dropping by 35.6%, but the decrease in relative water content has been 12.6%. Electrolyte leakage, proline and malondialdehyde content, catalase, and guaiacol peroxidase activity have increased under salinity stress condition. The Q26 cultivar has had the highest content of carotenoids, chlorophyll a, relative water content, soluble proteins, proline, and catalase activity, compared to the others. Titicaca cultivar has had lower malon-dialdehyde (MDA) content and electrolyte leakage than Q26 and Giza1 cultivars, which indicates the least damage to cell membranes, being superior to the other two cultivars. Giza1 cultivar also has had higher chlorophyll b and carotenoids content than the other two cultivars. Q26 and Giza1 cultivars are probably the most resistant and sensitive cultivars to salinity stress, respectively.