Climate is a major driver of plant phenology and a key determinant of species geographic distribution. Anticipating the effects of climate change on crops is essential for helping producers make informed decisions and implement adaptation strategies. Here, we propose a process-based phenological model for Asparagus officinalis in temperate production areas and use it to assess cultivation suitability across continental France.

Asparagus officinalis is an herbaceous perennial crop grown worldwide and broadly adapted to different climatic regions, whose phenology has received limited attention. We propose two possible models that simulate the annual progression of asparagus phenology: i) a sequential model, where chilling is strictly required for budbreak, and ii) an alternating model, where chilling acts as an accelerator of the subsequent forcing process. Both models include a cooling phase, after the summer solstice, that triggers the onset of dormancy.

We calibrated model parameters both from literature data and approximate budbreak dates across several asparagus-growing locations in western France. According to the Akaike information criterion (AIC), we selected the sequential model as the best. We eventually used it to project phenological transitions under different future Shared Socioeconomic Pathways (SSPs) to identify areas that will be suitable for production in the next decades, by considering both climate requirements and soil characteristics.

Our results suggest that a chilling period is needed to break dormancy in French cultivars. However, further research is needed to understand the biological mechanisms behind asparagus dormancy. Milder winters may hinder the release of endodormancy in the future, potentially leading to abnormal development and budbreak failure. In addition, the duration of the vegetative phase may shift as a consequence of changes in cold exposure. Suitable production areas are expected to move toward northern regions, where chilling requirements are more likely to be met and conditions for vegetative development may remain more favorable.