Global Trial Shows Arabica Variety Performance Changes With Climate

A new global Arabica coffee study has found that variety performance changes materially with climate, strengthening the case for matching planting material to local growing conditions rather than treating one cultivar as the best choice everywhere.

Published in Scientific Reports on October 2, the analysis drew on an international multi-environment trial covering 32 Arabica varieties at 30 sites in 17 countries. Researchers evaluated both yield and coffee leaf rust severity, creating a rare cross-country dataset for a crop that is produced on roughly 12.5 million farms worldwide.

The team used factor-analytic mixed-effects models to separate genetic performance from site effects and genotype-by-environment interactions. It then linked the resulting environmental patterns to climate variables through partial least-squares regression. That approach is designed for trials in which the same genetic material responds differently across locations.

Yield stability was most strongly associated with thermal gradients. The analysis distinguished performance in cooler locations with large differences between daytime and nighttime temperatures from performance in warmer environments where temperatures were more stable.

Coffee leaf rust followed a more complex environmental pattern. Variety-by-site differences in rust severity were associated with combined gradients of temperature, precipitation, humidity and thermal variability, rather than with a single climate variable.

The practical implication is not that breeders have identified one universal winner. It is that variety recommendations become more useful when they account for the climate profile of the target production area and evaluate yield together with disease pressure. A variety that performs consistently in one thermal regime may not retain the same advantage in another.

World Coffee Research began the International Multilocation Variety Trial in 2015 to compare leading Arabica material under standardized protocols across producing countries. Participating research partners monitor traits including productivity, plant vigor, disease incidence, bean characteristics and cup quality, while countries can use local results to guide variety access and multiplication.

The study provides a stronger empirical basis for climate-aware replanting and breeding, but it does not replace local trials or guarantee farm-level results. Soil, management, shade, planting age and future pathogen change still influence performance. The most defensible use of the findings is therefore as a framework for targeting varieties and designing the next generation of location-specific field testing.