Work

The cold truth: low temperature exclusion biases accurate estimation of base temperature but has limited impact on optimum and ceiling temperatures

Year: 2026

Type: article

Abstract: Accurate estimation of cardinal temperatures is essential for modeling crop germination responses to climate variability, yet experimental design strongly influences parameter reliability. This study systematically evaluated how truncated incubation ranges—excluding low (<10 °C) or high (>30 °C) temperatures—affect cardinal temperature estimates. Germination datasets from ten crop species were analyzed under four experimental scenarios using three non-linear response models, with model validity assessed through AIC, BIC, R², and RMSE. Results demonstrated that excluding sub-optimal low temperatures critically compromised the estimation of base temperature (Tb), inflating or deflating values by up to 40% relative to full-range estimates. In contrast, optimum (To) and ceiling (Tc) temperatures were stable across scenarios, with deviations consistently <5%. The heightened sensitivity of Tb reflects both mathematical imprecision when low data points are absent and physiological processes regulating germination onset. Warm-season crops with intrinsically higher Tb values exhibited less bias than cool-season species, underscoring species-specific vulnerability to truncated ranges. These findings highlight the necessity of including low-temperature treatments in germination experiments, particularly for crops with suspected low Tb values. By contrast, omission of supra-optimal (>30 °C) data introduces minimal error, confirming the robustness of Tc estimation. We propose standardized low-temperature protocols and species-specific modeling approaches as critical prerequisites for reliable cardinal temperature determination. Such methodological rigor will improve the predictive power of crop models, refine cultivar screening, and strengthen breeding strategies for climate resilience.

Source: Agricultural and Forest Meteorology

DOI: 10.1016/j.agrformet.2026.111150

Authors: Elias Soltani, Neïla Ait Kaci, Philippe Debaeke, Pierre Maury, Jay Ram Lamichhane

Institutions: Institut National Polytechnique de Toulouse, University of Tehran, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, AGroécologie, Innovations, teRritoires, Université de Toulouse

Language: English

Topic: Seed Germination and Physiology

Subfield: Plant Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Zero hunger

Open Access status: hybrid

Estimated APC paid: $3,590