University of Tabriz Journal of Plant Physiology and Breeding 2008-5168 16 2 2026 05 22 Effects of hydrogel polymer on grain yield, some physiological characteristics, and antioxidant enzyme activity of maize in response to drought stress 39 52 21345 10.22034/jppb.2026.70686.1401 EN Mostafa Shouridehdel Agronomy and Plant Breeding Department, Shahrood University of Technology, Shahrood, Iran. Mostafa Heidari Agronomy and Plant Breeding Department, Shahrood University of Technology, Shahrood, Iran. Hamid Abbasdokht Agronomy and Plant Breeding Department, Shahrood University of Technology, Shahrood, Iran. Journal Article 2025 12 12 <strong>Objective:</strong> Drought stress has destructive effects on the growth and performance of crops. The application of superabsorbent polymer can provide water and some nutrients to crops during the growth period. This experiment aimed to evaluate the effect of hydrogel polymer and drought stress<strong> </strong>on the characteristics of maize (variety MV 524 Maxima).<br /><strong>Methods: </strong>The experiment was conducted as a split-plot design based on a randomized complete block design with three replications. The drought stress levels, 60 mm (control), 120 mm, and 180 mm, based on evaporation from the evaporation pan, were assigned to the main plots. The levels of hydrogel polymer, 0 (control), 75, 150, and 225 kg/ha were arranged in subplots.  Hydrogels were mixed and applied at a depth of 20-30 cm in the soil. Samples were taken from young leaves at the seed-filling stage to measure photosynthetic pigments and antioxidant enzymes activity. Also, at maturity, mineral elements (nitrogen, phosphorus, and potassium) in the grains, biomass, grain yield, and yield components, including 1000-kernel weight, number of kernels per row, number of kernel rows per ear, and plant height were measured.<br /><strong>Results:</strong> Drought stress reduced photosynthetic pigments (chlorophyll “a”, chlorophyll “b” and carotenoids), N, P, and K content in the grains, the number of kernels per row, number of kernel rows per ear, and 1000-kernel weight. Also, drought stress increased the activities of catalase (CAT) and glutathione peroxidase (GPX). The application of hydrogel polymer had a positive effect on maize plants and at all drought levels, the highest grain yield, biomass, and number of kernels per row were obtained with the highest amount of hydrogel polymer (225 kg/ha). However, hydrogel polymer decreased CAT activity and anthocyanin content, but it did not change the number of kernel rows, 1000-kernel weight, ion content in the grains, GPX activity, chlorophyll “a” and “b”, and carotenoids in the maize leaves.<br /><strong>Conclusion:</strong> The results indicated that the application of 225 kg/ha hydrogel polymer had a beneficial effect on maize and mitigated the harmful effects of drought stress. https://breeding.tabrizu.ac.ir/article_21345_0bfa24f997a40da1cd094e9e8fdd85f5.pdf