Abstract
Introduction. Increasing climate variability and the growing frequency of drought events have intensified the need to develop effective approaches for improving the productivity and grain quality of spring wheat. The application of modern foliar biostimulants and plant growth regulators capable of enhancing plant tolerance to abiotic stresses represents a promising strategy. Materials and Methods. The study was conducted in 2025 at Olzha Sadchikovskoye LLP, Kostanay Region, Kazakhstan, using the spring wheat (Triticum aestivum L.) cultivar Kanyuk. A large-scale strip-trial experiment covering 794.1 ha was established to evaluate the effects of «Zeromax Phos» (0.3 L ha⁻¹), an enzyme-based biostimulant (0.25 L ha⁻¹), and MEGAVit (2.0 L ha⁻¹). Grain yield was assessed by whole-plot harvest accounting and sample sheaf analysis. Agroclimatic conditions were characterized using ERA5-Land data. Descriptive statistics, correlation analysis, and regression analysis were applied. Results. The highest agronomic performance was achieved with «Zeromax Phos», which increased grain yield to 35.4 c ha⁻¹, exceeding the control by 1.7 c ha⁻¹ (5.0 %), while improving grain test weight by 34 g L⁻¹. The highest biological yield (61.07 c ha⁻¹) was recorded in the «MEGAVit» treatment. A strong positive correlation was identified between plant height and biological yield (r = 0.929, p < 0.001). Discussion. The results indicate that anti-stress foliar treatments have considerable potential under conditions of periodic water deficit. However, the findings should be confirmed in randomized experiments with an adequate number of replications. Conclusion. Under the agroclimatic conditions of the 2025 growing season, «Zeromax Phos» proved to be the most promising treatment for practical agricultural use, providing higher grain yield and improved grain quality. «MEGAVit» demonstrated a high potential for enhancing biological productivity and warrants further evaluation in multi-factor experiments with sufficient replication.