Reproductive sensitivity of winter maize to extreme heat events in southern Sonora, Mexico
1 INIFAP, Agroclimatology Norman E. Borlaug Experimental Station, P.O. Box 155, km 12 Norman E. Borlaug between 800 and 900 Yaqui Valley, Obregon City, Sonora, Mexico.
2 Autonomous University of Sinaloa, Faculty of Agriculture of the Fuerte Valley, Juan José Ríos, Sinaloa, Mexico.
3 INIFAP, Wheat Pathology Norman E. Borlaug Experimental Station, P.O. Box 155, km 12 Norman E. Borlaug between 800 and 900 Yaqui Valley, Obregon City, Sonora, Mexico.
4 INIFAP, Water Use and Management Norman E. Borlaug Experimental Station, P.O. Box 155, km 12 Norman E. Borlaug between 800 and 900 Yaqui Valley, Obregon City, Sonora, Mexico.
5 INIFAP, Maize Breeding Research Norman E. Borlaug Experimental Station, P.O. Box 155, km 12 Norman E. Borlaug between 800 and 900 Yaqui Valley, Obregon City, Sonora, Mexico.
Research Article
International Journal of Life Science Research Archive, 2025, 09(02), 077-083.
Article DOI: 10.53771/ijlsra.2025.9.2.0062
Publication history:
Received on 02 November 2025; revised on 08 December 2025; accepted on 11 December 2025
Abstract:
Maize is a strategic crop in southern Sonora, where the recent increase in temperature variability and the frequency of extreme heat events has altered the optimal conditions for its establishment. This study quantified the crop's exposure to critical temperatures and determined the sowing date that maximizes potential yield, identifying useful temperature thresholds for decision-making. The study was conducted during the 2022-2023 growing season in ten commercial maize fields established between November 14, 2022 and January 6, 2023 in the Yaqui Valley. Each field was georeferenced and equipped with OMEGA digital sensors to record hourly canopy temperature, supplemented with data from weather stations. Temperatures ≥ 30 °C between flowering and physiological maturity were excluded, and heat stress was defined as ≥ 3 h per day for ≥ 3 consecutive days at ≥ 34 °C. Yield was estimated using six random 1 m² samples per field. Data were analyzed using ANOVA and linear and nonlinear regressions, verifying statistical assumptions. The average yield was 15.02 t ha⁻¹ (CV = 14.03 %), with highly significant differences between sowing dates (p < 0.001). The sowing on November 14th achieved the highest yield (21.18 t ha⁻¹), while sowings established after December 13th showed progressive decreases. Thermal monitoring revealed variations in the frequency and intensity of temperatures ≥ 30 °C; the highest-performing fields recorded fewer hours ≥ 34–35 °C, while the lowest-performing fields accumulated more than 40 hours ≥ 35 °C and isolated events ≥ 38 °C. The performance response showed exponential behavior, with minimal reductions below 33 °C and accelerated losses from 34-36 °C.
Keywords:
Thermal threshold; Reproductive phase; Maize; Zea mays
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Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0