Aplicação foliar de zinco como estratégia para mitigar estresses abióticos na cultura do trigo, sob condições do ecótono Cerrado-Mata Atlântica

Abstract

The Brazilian Cerrado, particularly in the state of Mato Grosso do Sul (MS), offers a promising landscape for the expansion of wheat cultivation; however, it poses significant challenges due to water instability and high temperatures during the growing cycle—factors that induce abiotic and oxidative stress in the crop. Foliar fertilization emerges as a promising strategy for mitigating the effects of oxidative stress. In this context, zinc (Zn) stands out as an essential micronutrient for plants, playing a multifaceted role in metabolism (photosynthesis, carbohydrate metabolism, protein synthesis, growth regulation, and reproductive development) and antioxidant defense. This study aimed to evaluate the effect of foliar zinc (Zn) application at different phenological stages as a strategy to mitigate abiotic stresses in wheat under the conditions of the Cerrado-Atlantic Forest ecotone. The experiment was conducted in Dourados, MS, over two growing seasons (2024 and 2025), using a randomized complete block design with four replications. Seven foliar Zn application treatments (100 g ha⁻¹) were evaluated, including a control (no application), single applications (at stages GS2, GS10, and GS10.5.1), and split applications (GS2+GS10, GS2+GS10.5.1, and GS10+GS10.5.1), utilizing the cultivars TBIO Calibre (2024) and TBIO Titan (2025). The variables analyzed included plant height, spike length, number of grains per spike, number of grains per spikelet, number of spikelets per spike, thousand-grain weight, grain yield, test weight, protein content, peroxidase, and superoxide dismutase. Data were subjected to analysis of variance and Tukey’s test (p<0.05). Results from the 2024 season demonstrated that split Zn applications—particularly GS2+GS10 and GS10+GS10.5.1—promoted increases in yield components, such as plant height, spike length, number of grains per spike, and number of grains per spikelet. No significant effects were observed in the 2025 season. Although grain yield did not show significant differences between treatments in either season, yield increments of 20.38% (2024) and 8.68% (2025) were observed relative to the control. In both seasons, split management resulted in higher activity of the antioxidant enzymes Peroxidase and Superoxide Dismutase, with increases of 250% (2024) and 33.33% (2025) for the former, and 10.47% (2024) and 9.73% (2025) for the latter, demonstrating improved physiological stability. It was concluded that split foliar zinc application, especially at stages GS2+GS10 and GS10+GS10.5.1, constitutes an effective strategy to strengthen the wheat antioxidant system and optimize agronomic performance, providing greater resilience to the abiotic stresses typical of the Cerrado.