Abstract
Drought is one of the major constraints of wheat production, especially in rainfed wheat production systems. The objective of this study was to evaluate the effects of different silicon fertilizer formulations on the agronomic performance of diverse wheat genotypes under drought-stressed conditions. Twenty wheat genotypes were evaluated in field and greenhouse environments under non-stressed and drought-stressed and two silicon fertilizer formulations (granular and liquid potassium silicate) and untreated control. The four-way interaction involving genotype, environment, water regime and silicon formulation had a significant effect (p < .05) for aboveground biomass, productive spike number, hundred seed weight and grain yield. Granular silicon application was the most effective treatment both under non-stressed and drought-stressed conditions compared to the liquid and control treatments. Under field and drought conditions, the highest yielding genotype was MC18, which exhibited a mean grain yield of 4.17 t ha−1 with granular silicon, 2.56 t ha−1 with liquid silicon and 2.18 t ha−1 without silicon. The yield of genotype MC18 improved by 91.3% using granular silicon under drought-stressed and by 44.6% under non-stressed conditions compared with the untreated control. Granular silicon positively affected the drought stress tolerance indices compared to the liquid silicon and untreated control. The principal component biplot analysis revealed that liquid and granular silicon positively impact yield response for all test genotypes under drought-stressed and non-stressed conditions compared with the control. Silicon application reduced genotype variation for agronomic traits and enhanced agronomic trait relationships under drought-stressed conditions. Drought stress tolerance indices are influenced by silicon application. The effect of silicon has a direct and indirect effect on yield and yield components. Silicon fertilization can be considered as a mitigation measure to cope with the adverse effect of drought stress on wheat.