Foliar Spray of Silicon Confers Drought Tolerance in Wheat ( Triticum aestivum L.) by Enhancing Morpho-Physiological and Antioxidant Potential

Drought stress is one of the most severe environmental stresses and is a significant contributor to yield reductions in agricultural crops. Several agronomic approaches are recommended by the researchers and later followed by the farmers to minimize the drastic effects of drought. However, the exogenous application of plant growth regulators in combination with mineral nutrients is a recent, innovative strategy to overcome the damaging effects of drought. Here, we report a study aimed at investigating the protective effects of exogenously applied silicon (using potassium silicate or K 2 Si 2 O 5 as a source) to improve drought tolerance in wheat ( Triticum aestivum L.) grown under field conditions. The present study was carried out at Agronomic Research Farm area, Faculty of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur. The experimental field was laid out in a randomized complete block design with split plot arrangements (RCBD-Split), and four repeats. The treatments included: T 0 (control, water spray), and T 1, T 2, T 3 i.e. foliar application of K 2 Si 2 O 5 solutions at the rate of 1, 2 and 3%, respectively. The results showed that drought stress significantly affected the wheat yield by decreasing chlorophyll- a (1.07), chlorophyll- b (0.49), total chlorophyll contents (1.62), flag leaf area (38.33 cm 2 ), plant height (100.17 cm), number of nodes per plant (3.91), tiller height (92.42), number of tillers m −2 (191.17), spike length (7.58 cm), number of spikes per plant (10.25), number of grains per spike (25.08), 1000-grain weight (36.66 g), total dry weight per plant (309.75 g), biological yield (23,424 kg/ha), and grain yield (4564.2 kg/ha). On the contrary, the foliar application of 2% K 2 Si 2 O 5 considerably reduced the drought-induced damages by enhancing the chlorophyll- a (1.21), chlorophyll- b (0.64), total chlorophyll contents (1.92), flag leaf area (45.25 cm 2 ), plant height (123.50 cm), number of nodes per plant (5.25), tiller height (99.42), number of tillers m −2 (276.26), spike length (12.92 cm), number of spikes per plant (14.25), number of grains per spike (38.33), 1000-grain weight (44.33 g), total dry weight per plant (385.00 g), biological yield (24,000 kg/ha), and grain yield (5074.8 kg/ha). These findings suggest that the exogenous application of K 2 Si 2 O 5 could be utilized as a rapid, easy and effective approach to reduce drought-induced damages on wheat yield.