August 17, 2016

At-Risk Arabica: Why Aren’t Researchers Looking to Ethiopia?


It’s a bleak picture: a world in which Arabica is at risk of dying out, due to its astonishing 98.8% genetic similarity. It’s a level at which you could expect all the world’s Arabica to have derived from the same plant – and a level at which the plant is highly vulnerable to disease or to climate change.

But how likely is Arabica’s extinction to actually come true? And why aren’t more studies being done in Ethiopia, where wild Arabica grows?

SEE ALSO: The Price of Climate Change in Ethiopia: Extinction of Wild Arabica


Wild coffee forest in Gela, Ethiopia. Credit: Collaborative Coffee Source

Where Did “98.8%” Come From?

A diversity analysis on 847 Arabica coffee samples (germplasm) by World Coffee Research did indeed find a 98.8% genetic similarity between them. However, as an exporter and producer in Ethiopia, the birthplace of Arabica, I believe there is more to this story.

Ethiopia is a unique country. And it’s unique in many ways, but in particular it’s unique because it is the ideal terroir, or geographical and climatic conditions, for coffee. In fact, Ethiopia and South Sudan are the only places in the world where coffee grows naturally – and I’ve read, again and again and again, that thousands of varieties have been collected and identified here.

I’d like to argue that, even though the WCR’s study is undeniably bad news, there is still potential for genetic diversity. And since I know that Ethiopia won’t allow exports of its coffee seeds, I’d like to make the case for conducting research in Ethiopia, using Ethiopian facilities.


Breaking down Ethiopian coffee production. Credit: Collaborative Coffee Source

Putting Scientific Studies Under the Microscope

Before we start looking into the genetic variation of Arabica within Ethiopia, it’s worth taking a moment to think about what a scientific study actually tells us. This is not intended to disparage the WCR’s valuable work, but rather to ensure we consider this in the same way that researchers do. Because science is often conflated with truth – and that can have far-reaching consequences, both positive and negative.

Science – and in particular, one scientific study – is not a universal truth. Science is a method of investigation that allows us to reach facts, and a scientific study is an investigation in a specific context carried out for a specific purpose. This is why scientists repeat experiments with different samples and in different environments before they claim “scientific proof”.

Detailed analysis of the genetic diversity of coffee, using molecular tools such as the ones used by the WCR, has not been done extensively by the scientific community. In fact, until now, there has only been a small amount of investigation into this topic. The WCR’s research is a useful and highly scientific starting point; however, further explorations of this will benefit us all.

There are three areas in particular that I would welcome greater analysis of.


Even scientific studies need to be examined.

1. Would a more diverse sample provide different results?

The samples were provided by The Tropical Agricultural Research and Higher Education Center (CATIE) in Costa Rica. Many researchers have reported that CATIE’s coffee germplasm collections, as well as their cultivated varieties, showed a high genetic similarity/narrow genetic-base due to the historic dissemination and propagation of the Arabica coffee.

However, can these samples really represent the whole diversity of Arabica? Would different samples give more positive results?

Hanna Neuschwander of WCR says, “Our study analyzed the collection of Arabica coffees held by CATIE in Costa Rica, plus some additional accessions from Yemen, where coffee was first commercially cultivated for trade – a total of 847 coffees. About half of CATIE’s collection is made up of Ethiopian coffees, mostly wild types or landraces, and mostly collected in the 1960s. It is a subset of all possible Arabicas, wild or cultivated.”

Those Ethiopian samples are now about 60 years old. Yet Davis and Moat (Senior Research Leader and Research Leader at Kew Royal Botanic Gardens respectively) have established that the forests of Ethiopia still hold 95% of the genetic resources of coffee. Ethiopia no longer allows samples to be removed from country, for either research or farming purposes. The question is: would a sample that included wild Ethiopian Arabica collected this year yield a better result?

It’s worth mentioning that, even if a different sample produced better results, it still wouldn’t mean that Arabica is in the clear. Hanna Neuschwander says, “Crops like maize, rice, and soy have been found to have diversity rates closer to 20-30%… Is total actual diversity larger than 1.2%? Almost certainly. Is it likely to be as large as 20%? Almost certainly not.”

2. Is the WCR’s proposed breeding pool diverse enough?

The WCR’s answer to the genetic similarity of Arabica is to begin breeding for diversity. It intends to establish a Core Collection of 100 Arabica varieties that would become the source from breeders to work with.

Yet if there are questions over the diversity of the research samples, then there must also be questions over the diversity of a collection derived from those samples. We don’t know if one that included wild Ethiopian Arabica would be a better breeding pool.

3. Is there a faster way to increase diversity via breeding?

In the words of the Executive Director of the WCR, Dr. Tim Schilling, the aim is to “recreate Arabica, but with better breeding”. More research into the best breeding techniques for increasing Arabica’s diversity may, over time, see greater genetic variation – but will it be fast enough? And would it be better to begin with wild Ethiopian samples? More research will help in answering those questions.

Coffee sack with an outline of Africa on it

Does Ethiopia hold the future of coffee?

A Glimmer of Hope: The Case for Genetically Diverse Wild Ethiopian Arabica

Even though Arabica appears to have a far below average amount of diversity, there is significant evidence in support of genetic variability in the forests of Ethiopia. 

In 2014, a collaboration between the Addis Ababa University and Freie Universität Berlin used ISSR Fingerprinting (essentially fingerprinting of the DNA of plants, mould, and bacteria). They found that there is genetic diversity within geographical regions in Ethiopia and that most regions in the wild forests of Ethiopia have their own unique genotypes – in particular, the wild populations taken from Yayu, Harenna in Bale, Bonga, Berhane Kontir, and Boginda are clearly distinct from landraces/cultivars.

Another study, by Tereesa and Crouzillat in combination with the Nestle Centre for Research in 2010, used 32 mircosatellite (SSRs) markers to find found a “high genetic variability reserve with a lot of specificity” that led to “a high potential” for the use of Ethiopian Arabica for improving genetic diversity.

CROPPED 22659103394_c655aa8a28_k

Wild coffee growing in Ethiopia. Credit: Collaborative Coffee Source

So Is There Genetic Diversity in Coffee?

There’s a lot of evidence both for and against genetic diversity in coffee, but the most important conclusion that we should take from it is that – regardless of the exact amount – genetic variability has severely decreased.

This has been caused by a range of factors: human population growth putting pressure on the wild forests of Ethiopia, new varieties that have been developed and disseminated over the last decades that have eventually pushed back the original local varieties, deforestation with its consequent genetic culling, and more.

One thing is certain: whatever genetic variability currently exists, it must be preserved – not only for the future of Ethiopian coffee, but for the future of coffee worldwide.

Roasted coffee beans

Not all coffee beans are (genetically) the same.

How Can We Increase Diversity in Coffee?

I believe that the strongest hope for increasing diversity in coffee currently lies within the wild forests of Ethiopia, home to 95% of coffee’s genetic resources. These forests provide the best genetic base from which to form resistance to drought, disease, temperature extremes, and all other effects of climate change – as also argued by Tadesse Woldemariam Gole in 2015. 

The question that remains is where and how to preserve such a genetic pool: in a laboratory in Costa Rica, in gardens in London, or in Ethiopia, where wild Arabica absent from other research collections is available.

I am of the opinion that Ethiopia must develop both ex-situ and in-situ germplasm centers. Coffee farmers all around the world are counting on the development of these facilities.

And where better to conduct further research into the genetic variation of Ethiopian Arabica than Ethiopia itself?  

With thanks to Melanie Leeson of Collaborative Coffee Source and Tadesse Benti Ergie for their input and reference-checking. Feature photo by Isai Symens.

All views within this opinion piece belong to the guest writer, and do not reflect Perfect Daily Grind’s stance. Perfect Daily Grind believes in furthering debate over topical issues within the industry, and so seeks to represent the views of all sides.