Distribution map for indigenous (wild) C. liberica (Liberica), C. dewevrei (excelsa) and C. klainei. Image shared via Creative Commons CC BY license. The original appeared in the study “Genomic data define species delimitation in Liberica coffee with implications for crop development and conservation” by A. P. Davis et al.
Recent genetic analysis revealed that liberica — which has historically been considered a single coffee species — may actually encompass three distinct species.
The findings could carry implications for coffee conservation, breeding and farming as the coffee sector continues to be reshaped by climate change. They also help clear up some common misconceptions about the coffee types commonly known as liberica and excelsa.
Led by a team at the UK-based Royal Botanic Gardens, Kew, with research partners in Uganda and Cameroon, the study proposes rewriting the taxonomic book on liberica, which has a long and interesting history of cultivation and commercialization dating back to the 1800s.
The study was published Aug. 8 in the journal Nature Plants.
Three Species: Liberica, Excelsa and Klainei
Using cutting-edge genomic analysis, the researchers sequenced 353 nuclear genes from 55 plant samples. The genetic data revealed distinct evolutionary lineages aligning with morphological differences and geographical distributions.
In short, the research proposes three separate species: C. liberica (a.k.a liberica); C. dewevrei (a.k.a. excelsa), and the newly recognized C. klainei.
The indigenous (wild) distributions of Liberica and excelsa do not overlap. Additionally, “the climate profiles of wild Liberica and excelsa coffee are markedly different,” study lead author Aaron Davis told DCN.
Reclassification Implications
The newly recognized C. klainei, previously dismissed as merely a synonym of C. liberica, emerges as a poorly understood species found in West-Central Africa including Cameroon, Gabon, and Angola.
Meanwhile, the newly classified C. liberica (liberica) and C. dewevrei (excelsa) should be the focus of continued study for potential commercial cultivation, the authors suggested.
An excelsa plant. Daily Coffee News photo by Nick Brown.
“Liberica and excelsa hold substantial potential for developing coffee farming in areas that are unsuitable for Arabica or robusta, particularly those at low elevations in hotter and wetter climates,” the study states.
The taxonomic revision could also carry sobering conservation implications. The redefined liberica now has a dramatically reduced native range, occurring naturally only in five West African countries, while representing a 95% reduction from previous estimates.
The authors noted that liberica consumption is experiencing “a renaissance” in parts of Southeast Asia, particularly in Malaysia, Indonesia and Fiji.
They noted that excelsa is finding some footing in Uganda, South Sudan and Guinea for its ability to “grow and produce commercially viable crops under higher temperatures and extended periods of low rainfall compared with robusta,” while cultivation is also rising in India, Vietnam and Indonesia to diversify production.
Setting the Record Straight
Beyond delineating the new species, the authors sought to clarify some global coffee statistics surrounding liberica and excelsa.
“Online sources regularly state that ‘Liberica’ (that is, C. liberica and C. dewevrei) provides 1–2% of the global coffee supply. This is incorrect, as these percentages are based on figures from the late-nineteenth century, when C. liberica stood with Arabica as the second most important coffee of commerce,” the study states.
Today, the authors suggest, global production of liberica and excelsa is “probably less than 1,000 metric tons,” which would represent about 0.01% of global coffee exports.
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Nick Brown
Nick Brown is the editor of Daily Coffee News by Roast Magazine.
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