Influence of Silicon Forms on Nutrients Accumulation and Grain Yield of Wheat Under Water Deficit Conditions

Abstract

Wheat productivity is severely hampered by drought, owing to its negative impacts on crop growth and development. For obtaining better yield, the impacts of drought should be ameliorated. Therefore, the current study scrutinizes the potential of different silicon (Si) forms to minify the drought-associated reduction in yield and the changes in nutrients accumulation. In a strip plots design based on randomized complete block arrangement using 3 replicates, two field experiments were carried out in 2019/20 and 2020/21 seasons. Three silicon (Si) forms (potassium silicate, calcium silicate, and aluminum silicate), in addition to the control (tap water) were sprayed. Also, three irrigation regimes were applied as ratio of crop evapotranspiration (60, 80 and 100%, denoted Irr60, Irr80 and Irr100, respectively). Findings clarified that application of aluminum silicate in both seasons, in addition to calcium silicate in the second season recorded the maximum accumulation of Si in wheat plants. Supplying wheat plants with different forms of Si reduced zinc (Zn) and manganese (Mn) and increased Si compared to the control (no Si application). Irr100 possessed increase in accumulation of Si in plant tissues greater than Irr80 or Irr60. Significant increases in all agronomic traits of wheat were obtained owing to spraying any Si form compared to the control. The differences between potassium silicate, calcium silicate, and aluminum silicate were not significant in flag leaf greenness (SPAD value), grains weight spike⁻¹, weight of 1000 grains, and grain yield ha⁻¹ in 2020/21 season. Irr100 was the effective treatment for enhancing SPAD value, spike length, grains weight spike⁻¹, weight of 1000 grains, and grain yield ha⁻¹. When irrigation water was reduced by 20% (Irr80), the lowest reduction in grain yield was obtained with potassium silicate compared to other forms of Si. It could be concluded that since lower accumulation of Si in plant tissues under water deficit than well-watered was recorded, the spraying of Si is great of importance to be applied under drought stress.