From flowering to grain filling: thermal sensitivity and yield response of Arabica coffee under climatic variability

CONTEXT : Coffee yield is influenced by climatic factors, with temperature and water availability being key determinants. OBJECTIVE : To assess the effects of climate variability on the yield of Arabica coffee cultivars across phenological phases and to validate an agrometeorological model at local and regional scales using yield–climate time-series data from the Volcanic Region of Poços de Caldas. METHODS : The Arabica coffee cultivars Mundo Novo 376/4, Catuaí IAC 144, and Bourbon Vermelho were evaluated across four phenological phases. Pearson’s correlation coefficients were applied for each phenological phase and production year between yield and climatic variables, along with the Mann–Kendall test to detect monotonic trends in climatic data. The agrometeorological model was evaluated at different analytical scales and under distinct cultivars and yield scenarios, using historical data from 2011 to 2024. RESULTS AND CONCLUSION : The grain-filling phase was the most sensitive to increasing temperature, while flowering showed a rising warming trend, increasing its vulnerability. Cultivars differed in their thermal and water tolerance, with Bourbon Vermelho showing high vegetative resilience but marked reproductive susceptibility. The model performed well at the regional scale (R² = 0.93; RMSE = 453 kg ha ^-1 ), particularly within the Volcanic Region, but exhibited limited accuracy at the plot scale due to local variability. Estimated yield losses were mainly associated with water deficit, followed by frost events, while thermal penalties were minimal. SIGNIFICANCE : Improvement of climate-resilience strategies and mitigation of climate-change impacts on coffee cultivation.