Selenium-induced modulations in growth, productivity and physiochemical responses to water deficiency in Quinoa (Chenopodium quinoa) grown in sandy soil

Water stress is one of the major global problems that limits the growth and production of various crops. The current investigation aims to study the possibilities of mitigating the effect of drought stress on Quinoa plant grown under sandy soil by foliar treatment with selenium through assessment growth, productivity, and many physiological and biochemical measurements. Selenium (SE) was exogenously-applied as a foliar treatment with concentrations SE 25 mg/L and SE 50 mg/L to Quinoa plants grown under (full irrigation I 100 = 100%) and (deficit irrigation I 60 = 60%) in open field in growing seasons (2019/2020 and 2020/2021). Exposure of Quinoa plants to water stress led to significant decreases in shoot growth, yield, chlorophyll a , chlorophyll b , carotenoids and indole acetic (IAA) comparing with full irrigation (I 100 ). While, increased root length, fresh and dry weight, total phenolics, total soluble sugars TSS, proline and free amino acids (FAA). Furthermore, water deficit decreased yield and its components as well as carbohydrates, protein, nitrogen, phosphorus and potassium contents of the yielded Quinoa grains compared with those plants grown under normal irrigation (I 100 ). However, foliar spraying with selenium particularly at 50 mg/L to stress plants significantly improved growth and productivity of Quinoa plants. Moreover, treatment Quinoa plant with different levels of selenium reduced the effect of water stress by enhancing growth and productivity of Quinoa plants through improving photosynthetic pigments , IAA , total phenolics, TSS, proline and FAA contents. As a result, this findings suggest using 25 or 50 mg/L selenium as a foliar application strategy for Quinoa plants grown under drought stress to maintain higher growth and the studied biochemical aspects and yield as well as yield components and mitigate the inhibitory action of water stress on plant growth and productivity. • Exposure of Quinoa plants to water stress led to significant decreases in shoot growth, via decreasing of chlorophyll a , chlorophyll b , carotenoids and indole acetic (IAA) comparing with full irrigation (I 100 ). While, increased root length, fresh and dry weight, total phenolics, total soluble sugars TSS, proline and free amino acids (FAA). • Furthermore, water deficit decreased yield and its components as well as carbohydrates, protein, nitrogen, phosphorus and potassium contents of the yielded Quinoa grains compared with those plants grown under normal irrigation (I 100 ). • However, foliar spraying with selenium particularly at 50 mg/L to stress plants significantly improved growth and productivity of Quinoa plants. • Moreover, treatment Quinoa plant with different levels of selenium reduced the effect of water stress by enhancing growth and productivity of Quinoa plants through improving photosynthetic pigments, IAA, total phenolics, TSS, proline and FAA contents.