Prospects of decreasing winter chill for deciduous fruit production in Chile throughout the 21st century

Abstract

In Mediterranean climates, many deciduous fruit trees are unable to meet their seasonal chill requirements, a situation that may be exacerbated by global warming. Modeling approaches can be used to assess the impacts of climate change on tree crops for the past and forecast possible impacts for the future. We apply modeling approaches to assess climate change impacts on Chilean fruit production in nine major agricultural sites. Using a weather generator, we obtained 100 years of plausible weather data for scenarios produced by 15 climate models for two Representative Concentration Pathways (RCPs). Winter chill, safe winter chill (both quantified in Chill Portions - CP), and the percentage of years with spring frost were estimated for two reference years, 2050 and 2085. Projections show a considerable chill reduction in northern regions in all future scenarios. Relatively stable conditions are projected for southern regions, whereas most of the central sites are expected to lose between 10 and 15 CP by 2050. For 2085, expected chill reduction is much more severe. The percentage of years with spring frost is projected to decrease in all locations, varying according to RCP scenario and year. Results highlight that in northern sites, some species may fail to meet their chill requirements in the future. In other regions, strategies to mitigate the effects of chill shortfalls may become critical to ensure adequate yields. Results may be useful for geneticists, breeders, physiologists, dormancy researchers, and growers making production decisions, e.g., on selection of appropriate species and varieties.