Augmenting Arabica’s Genetic Pool

Editors note: Gesha is an Ethiopian village and place name like Harrar or Yirgacheffe. Geisha is a coffee varietal.

GESHA, Ethiopia

By Dan Bolton

Coffee’s reproductive biology limits its ability to improve its lot in life.

“It mostly reproduces by self-fertilization which occurs in about 90% of the flowers,” according to Dr. Sarada Krishnan, a coffee plant expert and director of horticulture at the Denver Botanic Gardens in the U.S.

The result is countless varieties in its native Ethiopia – and a very, very small gene pool among arabica grown elsewhere.

Dr. Aaron Davis, leader of coffee research at the Royal Botanic Gardens, Kew, U.K., reports that only 0.03% of the genetic diversity available in coffee can be found in commercial farms worldwide. This is one reason why coffee is highly susceptible to pests and diseases such as coffee leaf rust (CLR).

“Enlarging the genetic base and improvement of arabica cultivars have become high priorities for researchers,” writes Krishnan.

“In Ethiopia we have the opportunity to save the world’s most astounding coffee cultivar, geisha, by reproducing the mother trees of this variety to preserve this unique genotype for many future generations,” adds Dutch coffee consultant Willem Boot.

Enhancing coffee vigor is why in 1931 the British government tasked its consul in Ethiopia, R.C.R. Whalley, with obtaining coffee samples to plant in Kenya and Tanzania (the former German East Africa which gave way to British rule after World War I). It was the practice then for coffee farmers to plant many species. As the birthplace of arabica, Ethiopia offers the greatest genetic diversity of all.

Samples, named for the nearest location where they grew, were sent to agricultural research stations for evaluation. One variety the diplomat chose by happenstance proved robust, disease resistant, and intensely flavorful (although that trait would not be revealed for decades). The seeds are believed to have been sourced in the western highlands near Maji and Goldija. The coffee was labeled with some variant of Gesha, one of three like-sounding places (Gesha, Geiscia, and Gescia) in Pueblos Unidos, Ethiopia. At the time it was just another seed in the sack.

When planted at 1,400 meters and below the elliptical cherry from the tall and gangly, low-yielding plants revealed little promise in the cup. Fortunately researchers in Tanganyika discovered that the big oval leaf trees showed some resistance to disease – especially fungus. This is why the varietal was sent in July 1953 to Costa Rica’s coffee research center, the Coffee Institute Inter of Agricultural Sciences (IICA) and later to the Tropical Agricultural Research and Higher Education Center (CATIE).

In 1963 the coffee made its way to Panama where seeds obtained by Don Pachi Serracin were planted in the mountains near Boquete, an ideal high-mountain terroir at 3,900 feet and up. Trees from Gesha also found their way to Jamaica, Brazil and Colombia where researchers sought fungus-resistant varieties but in Panama the cherry from these trees literally blew past the competition.

No one knows exactly why, but in time the New World plants came to be known as geisha, a varietal that today is judged to produce some of the finest coffee in the world. Retailers have bid as high as $350 per pound since 2004. Lots generally sell for at least $50 per pound in a specialty market that buys every pound offered.

That is why 80 years after geisha left Ethiopia Boot found himself mired in mud looking for a needle of a tree in 425,000 square mile haystack of undeveloped country.

Boot, 54, is a grower, consultant and professional coffee taster who roasted his first batch of coffee at the age of 14. He speaks six languages and has a master’s degree in business economics from the University of Amsterdam. The Dutch native splits his time between Panama, where he owns Finca La Mula and co-owns Finca Sophia, farms with a total of 35,000 geisha trees, and Mill Valley, near San Francisco. Companies and organizations from around the world have employed the expertise of his California-based Boot Coffee Consulting since 1998. He offers hands-on advanced training from seed to cup. His obsession with geisha dates to 2004.

Boot is keenly aware of the vulnerability of arabica. He knows first-hand the devastation caused by la roya (coffee leaf rust) and the coffee berry borer, a beetle that spread from Africa to the Americas with a host of plant diseases. His personal goal is to improve the quality of every aspect of coffee. 

DNA is fundamental, he explains. According to Boot, planting the right variety to prevent major pests and diseases is ultimately the key decision a grower can make. “Instead of applying massive amounts of chemicals, growers should first look at the options provided by the natural pool of genetics provided by Mother Nature,” he said.

Genetic diversity

Ethiopia is home to an estimated 40,000 wild varieties of coffee. Despite the passage of eons, most of this coffee resembles its ancestors.

This is why Boot sought to discover the link between the geisha that migrated to Panama and the trees at origin. Since the variety evolved its resistance to rust over many centuries during which the ambient temperature and rainfall varied, it is safe to assume there are similar relatives whose adaptations remain in their gene stock.

Returning to Ethiopia is a first step in the long process of invigorating coffee globally.

During the past five years the task has taken on new urgency. The spread of the la roya fungus depends on rain, wind, and higher temperatures. It was largely confined to low altitudes after its arrival in Puerto Rico in 1903. It was eradicated in the New World soon after and did not emerge as a threat until infecting Brazil in 1970. It then spread to Nicaragua in 1976 and is now found throughout Central and South America at higher elevations where arabica thrives. Countries that are experiencing the greatest impact such as El Salvador, Nicaragua, Honduras, and Guatemala (See Guatemala Report, Pg. 40) simply do not have the resources to combat the symptoms without attacking the root cause.

Robusta (coffea canephora), which was first discovered in 1898 in what was then the Belgian Congo, has developed a strong defense against roya but does not deliver the satisfying taste of a high grown arabica. Agronomists, during a period of 50 years, have since created several arabica hybrids that display resistance and taste good which is a promising development.

Unfortunately there are many races of coffee rust with varying degrees of virulence. These newer strains of the pathogen are unaffected by the resistance genes within specific cultivars which often take many years to develop.

Geisha goodness

Geisha T.2722 is resistant to Race II but susceptible to six of the 49 known races of la roya. Due to its low yield, geisha was initially rejected in favor of red caturra. The discovery of the Ethiopian mother stock could tip the balance in favor of geisha as there are no caturra or catuai coffees with cupping scores that rival geisha. In the past 11 years of Cup of Excellence competition hybrids have never won the top prize.

“Rust resistant hybrids that cup well are today’s Holy Grail for coffee farmers around Latin America,” said Boot. “Countries including Colombia and Honduras have booked great results with the development of new, higher quality, rust-resistant hybrids like castillo and lempira,” he said. 

Once the technical hurdles are behind there remains a political challenge. Ethiopia is a landlocked country without a single rail line. The people of Ethiopia have been exploited for centuries leading to poverty, insurrection, and general distrust of Europeans and those from the New World.

Boot is optimistic, “Hopefully, the Ethiopian government recognizes the development of hybrids as an economic opportunity and maybe this could lead to the production of super quality rust resistant varieties in the near future.”