Populations of potentially drought resistant wild Robusta coffee have been identified by a team of Ugandan, Dutch and French scientists. The study raises hopes for developing drought resistant cultivars. But these populations occur in forests that are currently under threat of deforestation.
In her PhD research - to be defended at Wageningen University today on October 19 - Catherine Kiwuka collected a large number of hitherto unknown wild coffee robusta genotypes from Ugandan forests, and genetically researched and phenotyped them for drought tolerance. This led to the discovery of special coffee populations with climate-resistant properties. Robusta is in itself of inferior quality to arabica but is more climate-proof. And especially the Ugandan robusta is of a very high quality comparable to arabica. This can be attributed to the fact that Arabica originates from a natural hybridisation of robusta and another coffee species.
Highly endangered forests
The newly found robusta populations occur in forests that are generally very threatened. For example, the most valuable material is found in the Zoka forest in Northern Uganda, a remnant of about 10 km2 and highly endangered.
Furthermore, the study shows that, while the wild populations in the north western part of the country are genetically unique, those in the south of the country are already genetically mixed with cultivated material. Therefore the study highlights the importance of conserving and harnessing extant genetic resources in wild coffee populations, and it acutely points to the need to conserve and further investigate the material in Uganda.
Exploring genetic resources
Coffee is an important global commodity and its production sustains tens of millions mostly small-holder farmers across the tropics who are usually vulnerable to adverse effects of climate change. Coffee is also the main source of foreign income for Uganda. But estimates suggest that climate change through increased occurrence of droughts, heat waves and diseases is expected to cause 50% reduction in coffee production globally.
Exploring genetic resources extant in wild coffee populations for climate and disease resilience is a means to address this issue. While Robusta coffee is generally of lower quality than arabica, it is also more climate resilient and the Ugandan Robusta is renowned for its arabica-like cup quality.
Valuable coffee can help protect biodiversity and vice versa
“Uganda has an incredibly rich biodiversity which is seriously threatened by deforestation. For example, some of the forests studied and under threat include important chimpanzee populations. I hope Catherine's research will help increase the understanding that valuable coffee is vital for small farmers and can help protect valuable biodiversity and vice versa," said her promoter professor Niels Anten.