Arabica coffee is the world’s most economically important coffee species. Now, researchers have traced its origins to Ethiopia hundreds of thousands of years ago.

The international team of scientists, led by NTU’s Asst Prof Jarkko Salojarvi from the School of Biological Sciences, uncovered this by studying the genomic origins and breeding history of the Arabica coffee plant.

The plants analysed by the scientists included an 18th-century specimen that Swedish biologist Carl Linnaeus, the father of taxonomy, used to name the Arabica species.

From their research, the scientists postulated that Arabica stemmed from a chance event 350,000 to 610,000 years ago in Ethiopia, when two other coffee plant species naturally cross-pollinated to create the first Arabica plants in the wild.

The classic cultivated Arabica plants of today do not have resistance to the devastating coffee leaf rust – an infectious fungal disease that can destroy the plant.

The study found that this resistance may have been lost when Arabica plants became widely cultivated.

However, the researchers also identified a new combination of genes transferred from a different species of disease-resistant coffee plants, which could help protect Arabica plants vulnerable to coffee leaf rust.

The highly detailed genomic sequence of the Arabica coffee mapped by the study also means that other useful traits could be improved in the future. These include the coffee’s resilience under dry weather, better crop yield and more aromatic coffee beans.

---

Details of the study can be found in “The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars”, published in Nature Genetics (2024), DOI: 10.1038/s41588-024-01695-w.

The article appeared first in NTU's research & innovation magazine Pushing Frontiers (issue #24, October 2024).