• Excluding low (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 (T b ), inflating or deflating values by up to 40 % relative to full-range estimates. In contrast, optimum (T o ) and ceiling (T c ) temperatures were stable across scenarios, with deviations consistently 30 °C) data introduces minimal error, confirming the robustness of T c 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.
Soltani et al. (Fri,) studied this question.