Exploring the Potential of Silicon and Salicylic Acid in the Alleviation of Water Deficit Stress in Quinoa (Chenopodium quinoa)

Global warming and less uncertain rainfall have resulted in climate change and water deficit stress conditions which had a deleterious impact on the agroecosystem. Silicon (Si) exists as a beneficial component in soil and has a significant role in overcoming water scarcity problems. Si can maintain crop yield and growth even in stress conditions like salinity and water deficit stress. Salicylic acid supports the crop to withstand the harmful effects of salinity and drought stress. This growth regulator together with silicon works to alleviate the water deficit stress condition. A foliar spray of SA is beneficial for plants. A pot experiment was conducted in the greenhouse of the Institute of Soil and Environmental Sciences to evaluate the effect of Si (Control, 100 and 200 mg kg^-1) and SA (Control and 1 mM) on quinoa under water deficit conditions. Treatments included: T₁ = Control, T₂ = Si at 100 mg kg^-1, T₃ = Si at 200 mg kg^-1, T₄ = 1 mM SA foliar, T₅ = Si at 100 mg kg^-1 + 1 mM SA foliar, T₆ = Si at 200 mg kg^-1 + 1 mM SA foliar, T₇ = Water deficit, T₈ = Water deficit + Si at 100 mg kg^-1, T₉ = Water deficit + Si at 200 mg kg^-1, T₁₀ = Water deficit + 1 mM SA foliar, T₁₁ = Water deficit + Si at 100 mg kg^-1 + 1 mM SA foliar, T₁₂ = Water deficit + Si at 200 mg kg^-1 + 1 mM SA foliar. Two water levels, control (100% FC) and deficit water stress (60% FC) were used. In the first four weeks after germination, all pots were equally irrigated and after this, water deficit stress started. A completely Randomized Design (CRD) was used to establish the experiment with three replications under a factorial arrangement. The crop was harvested at the maturity stage. It was found that water shortage followed a substantial decline in the growth and yield of quinoa. However, Si and SA improved the fresh and dry weight of the shoot, plant height, SPAD value, RWC, MSI, and productivity of quinoa under normal and water stress conditions. Therefore, it is concluded that SA and Si applications proved effective in improving crop growth in deficit water conditions by increasing the deficit water stress tolerance of quinoa plants.