Effect of silicon dioxide application and potassium levels on morphophysiological properties and storable seed yield of hybrid super sweet maize (Zea mays L. 'Elika') under drought stress

In this experiment, we investigated the effects of drought combined with exogenous silicon (Si) and potassium application on super sweet corn growth and development. Drought stress caused decreases in the stem diameter, leaf area, cob length, cob diameter, 100 seed weight, seed number, cob yield, biologic yield, and relative water content (RWC), but proline content and catalase activity were higher under drought stress conditions. The results of a two-year experiment showed that potassium sulfate application and foliar application significantly increased RWC in drought stress conditions, and the highest increase was related to treatment with potassium sulfate in an amount of 25 kg/ha. Under normal irrigation conditions, with 25 kg of potassium sulfate per ha and Si foliar application, the maximum cob diameter (5.85 cm) was observed. Si application did not significantly affect proline content under normal irrigation conditions but increased proline content under drought stress. The highest proline content (10.77 mmol/g fresh weight) was recorded in the Si application using 25 kg of potassium sulfate per ha under drought stress conditions. Also, applying potassium sulfate with silicone foliar spraying had no significant effect on biologic yield under normal irrigation conditions. However, under drought stress treatments, biologic yield increased by applying 15 and 25 kg/ha of potassium sulfate and Si foliar spraying. In summary, applying potassium sulfate and exogenous Si can enhance the antioxidant system of the plant, promote the RWC, thus improving biologic and cob yield, and enhance the drought resistance of super sweet corn.