Thermal Vulnerability and Potential Cultivation Areas of Four Day-Neutral Strawberries in Chile: Implications for Climate Adaptation

Abstract

Understanding strawberry thermal resilience is crucial for optimizing cultivation in the face of climate change. However, its thermal niche remains underexplored. We assessed the thermal vulnerability of leaves and flowers in four day-neutral strawberry varieties cultivated in Chile and evaluated potential shifts in their suitable cultivation areas under warming scenarios. Tolerance to freezing, heat (LT₅₀), and Thermal Tolerance Breadth (TTB) were determined, and habitat suitability was modeled using MaxEnt under two climate change projections and time periods. Heat LT₅₀ of leaves and flowers was similar across strawberry varieties, averaging 56 °C. Conversely, the average freezing LT₅₀ of flowers was 12 K less negative than that of leaves across varieties. The TTB of leaves was generally broader than that of flowers, except for San Andreas, with Monterrey displaying the broadest TTB difference (14.6 K). Climatic models indicated slight southward shifts in suitable cultivation areas under warming in Chile and globally. Nevertheless, the potential for strawberry cultivation in the more southern regions will depend on the development and implementation of cultivation strategies that effectively minimize the risk of freezing damage to the flowers. This highlights the need to plan cultivation areas according to each variety's thermal tolerance to enhance resilience and sustainability in a changing climate.

Keywords: Fragaria × ananassa; LT50; day-neutral variety; electrolyte leakage; freezing; heat waves; production areas; strawberry; thermal niche.

Figure 1

Heat (a), freezing (b) tolerance (LT₅₀ °C), and thermal tolerance breadth (TTB) were determined in leaves and flowers of four strawberry varieties. Colors indicate organs: red for flowers and green for leaves. In (a,b), boxes indicate the average (=second quartile; line inside the box) and extend from the first to the third quartile. The whiskers show a maximum of 1.5-fold interquartile range. Circles represent outliers. Red and green brackets indicate significant differences in LT₅₀ across varieties (p < 0.05). Asterisks denote significant differences between leaves and flowers (*** = p < 0.001). In plot (c), the violin represents the density of the data distribution at different variable values. Boxes inside violins indicate the median (=second quartile; line inside the box) and extend from the first to the third quartile. The whiskers show a maximum of 1.5-fold interquartile range. Circles represent outliers. The green bracket indicates significant differences in LT₅₀ leaves across varieties (p < 0.05). Asterisks denote significant differences between leaves and flowers (*** = p < 0.001), n.s. represents non-significant differences.

Figure 2

Habitat suitability for Fragaria × ananassa projected in the present using the selected BIO variables calculated from historical WorldClim data for (a) Chile and (b) globally. The color gradient represents suitability, with warmer colors indicating higher suitability. Green points indicate hybrid species occurrences obtained from GBIF [62] after filtering, while red points represent occurrences obtained from the literature.

Figure 3

Projected changes in habitat suitability for Fragaria × ananassa based on the difference between the 2021–2040 period and the present, using selected bioclimatic variables from WorldClim and the GCM MPI-ESM1-2HR, for (a) Chile under the SSP2-4.5 and (b) SSP5-8.5 scenario; (c) the global scale under the SSP2-4.5 and (d) the SSP5-8.5 scenario. Red colors indicate a decrease (negative difference) in habitat suitability, while blue colors indicate an increase (positive difference) between the two time periods.

Figure 4

Projected changes in habitat suitability for Fragaria × ananassa based on the difference between the 2041–2060 period and the present, using selected bioclimatic variables from WorldClim and the GCM MPI-ESM1-2HR, for (a) Chile under the SSP2-4.5 and (b) SSP5-8.5 scenario; (c) the global scale under the SSP2-4.5 and (d) the SSP5-8.5 scenario. Red colors indicate a decrease (negative difference) in habitat suitability, while blue colors indicate an increase (positive difference) between the two time periods.

Figure 5

The elevated soilless system for strawberry cultivation at the Llahuén Experimental Center. (a) A general overview of the wooden modules where the plants were cultivated, highlighting the cover, irrigation system, and variety identifiers. The (b) panel shows the spacing between plants within each wooden module. These photographs are referential and do not represent the phenological state of the plants at the time of determining thermal tolerances. (Credits: A. Sierra-Almeida).