Biology subjects

Bancal, M.-O.

Publications and source records attributed to Bancal, M.-O..

4 recordsLinked to original sources

bioRxiv2026

Evaluating crop models for future climate scenarios: wheat yield predictions using APSIM and STICS under combined CO2, warming, and water deficit conditions

Crop models are essential for predicting climate change impacts on agriculture, yet their validation under multi-stress conditions remains limited. This study evaluated two widely-used wheat models, APSIM and STICS, using data from three Free-Air CO2 Enrichment (FACE) experiments (USA, Germany, Australia) combining elevated CO2 (eCO2), water deficit, and warming. Environmental characterisation using simulation-based stress indices revealed that intended "controls" frequently experienced hidden heat and water stress, meaning models were calibrated on crops already undergoing physiological adjustments. Evaluation of simulated yield and components revealed a clear hierarchy in prediction errors (RRMSE): unlimited conditions (3-9%) < single stress (4-27%, with a need to improve response to heat stress) < combined stress (17-123%). Elevated CO2 generally increased prediction uncertainty for crops experiencing water stress. Our results suggest that current stress functions from the models fail to capture the synergistic coupling between drought and heat stress. This highlights the urgent need for more mechanistic modelling to improve the reliability of climate change impact assessments.

plant biology↗

bioRxiv2025

Plant plasticity in the face of climate change - CO2 offsetting effects to warming and water deficit in wheat. A review.

Future crop production will depend on plant plasticity in response to increases in atmospheric CO2, mean temperature, heatwave and drought events. The present review intends to highlight the impact of interactions between high CO2 levels, warming and water deficit in existing published experimental data in the case of wheat. To do so, we identified experiments quantifying the effects of such interactions on traits related to crop productivity and water use. We used the collected data to estimate plasticity indices assessing compensation and interaction between elevated CO2 and adverse climatic conditions, bringing a new perspective on the matter. In the studied data, even though there is an important variability, we found that crop productivity tends to decrease despite the positive effects of the rise in CO2 concentration. Conversely, with elevated CO2, water consumption tends to decrease despite the warmer conditions. We hypothesized that the positive effect of CO2 on crop productivity is greater under drought conditions, which is confirmed in 54% of the experiments. This review highlights the need to acquire further experimental data under possible future conditions to calibrate and validate crop models: their range of validity requires more thorough testing under the wide range of projected environmental conditions.

plant biology↗

bioRxiv2025

Refining type and timing of measured crop variables for the calibration of a new winter wheat cultivar in the STICS crop model

Crop models need to be regularly upgraded with parametrization for new cultivars but this requires calibration, which is a major challenge. With winter wheat cultivar Rubisko as a case study, we propose to apply a calibration protocol to estimate the parameters of this new cultivar with multi-trials experimental data. We tested the calibration protocol in different conditions including or not LAI and/or biomass experimental data and we found that the resulting LAI and biomass dynamics strongly diverge. Several key findings emerge from this study: (1) RUE parameters should be excluded from the calibration process, as their critical role in biomass dynamics causes the optimization algorithm to treat them as adjustment parameters, resulting in unrealistic values for multiple parameters; (2) either LAI or biomass variables alone are sufficient for calibration, enabling experimental efforts to focus on one variable rather than both; and (3) the use of a synthetic dataset has facilitated the identification of the optimal type and timing of data collection needed to parameterize a new variety in the model. Moreover, the proposed methodology offers extrapolatable solutions applicable to other contexts (e.g., different models or datasets) and provides guidance on acquiring the most effective dataset for optimal calibration. The unbalanced structure of our dataset also highlighted the need to mobilize other calibration criteria (weighted RMSE) and alternative solutions to bridge the gap between quantitative metrics and empirical visual assessments.

plant biology↗

bioRxiv2024

Ecophysiological Behaviour Of Major Fusarium Species In Response To Combinations Of Temperature And Water Activity Constraints

Fusarium Head Blight (FHB) is a devastating fungal disease affecting cereals, caused by Fusarium species that can produce harmful mycotoxins. Fusarium species share the same ecological niche, and their population dynamic and associated mycotoxin patterns are driven by the environment. The aim of the present study was to investigate ecophysiological characteristics of the major Fusarium species causing FHB under abiotic factors. Growth and mycotoxin production of different strains of Fusarium avenaceum, Fusarium graminearum, Fusarium langsethiae, Fusarium poae and Fusarium tricinctum were characterized under a combined effect of temperature ({Theta} = 15, 20, 25 and 30{degrees}C) and water activity (aw = 0.99, 0.98, 0.97, 0.96, 0.95 and 0.94). Using innovative statistical analyses, we demonstrated that those Fusarium species greatly differ in their responses to the studied environmental constraints. Our findings indicated that {Theta}, aw, and their interaction were the major factors with a significant impact on the species behaviour. The intraspecific variation was demonstrated as less pronounced than the interspecific one. Understanding the ecophysiological requirements of Fusarium species is crucial in the context of climate change that is predicted to worsen disease outbreaks. Our data constitute a valuable knowledge base for improving the reliability and robustness of FHB prediction models and anticipating the associated mycotoxin risk. IMPORTANCEFusarium species pose a significant threat to major cereal crops, including wheat. These fungi not only reduce yield but also produce mycotoxins harmful to animals and humans. The prevalence of each Fusarium species is influenced by environmental conditions and shifts in pathogen populations, leading to changes in mycotoxin patterns have already been observed in relation to climate changes. This study revealed distinct ecophysiological behaviours, including mycelium growth and mycotoxin production, among the five major Fusarium species when exposed to varying temperature and water activity conditions. Our findings provide a valuable foundation for a more comprehensive understanding of the challenge of mycotoxin contamination and for the development of more effective mitigation strategies in the near future.

microbiology↗