Update on arabica coffee problems: cozying up to solutions

By Perry Luckett, CoffeeMan1

As incomes rise around the world, more people are drinking coffee. Canada consumes an average of 6.7 kilograms per capita annually, Brazil 6.2 kilograms, Italy 5.8 kilograms, and the United States (US) 4.5 kilograms. A US consumer survey found that Americans are crazy for caffeine, and that “52% of coffee drinkers would rather go without a shower in the morning than give up coffee.” [ACP]

Arabica coffee plants like this are under threat from climate change, disease, and pests. By Gaurav Dhwaj Khadka, CC BY-SA 4.0. https://commons.wikimedia.org/w/index.php?curid=83433864

That all sounds like good news for the coffee industry, but consumer taste also is moving toward high-quality arabica coffee—to the exclusion of other varieties. As an example, CEO Mark Dunhill of English coffee, tea, and cocoa retailer Whittard of Chelsea, says coffee has to be made with beans from Coffea arabica—a shrub discovered hundreds of years ago in the southwestern highlands of Ethiopia—or not at all. “Arabica beans provide a radically different and infinitely more pleasurable drinking experience,” Dunhill says. Because many of the world’s billion or so coffee drinkers agree, robusta beans typically go into instant coffee. [AS]

So why could increased demand be bad news for arabica production?

Mostly, it’s too much, too soon. Our The Perfect Cup page shows this preference for arabica coffee will require production to be at least 1 million tons higher by 2028 (ICO, 2016). At average yields of 780 kg of green coffee per hectare (ha) over the last few years, this would demand 1.3 million ha of new coffee fields largely from freshly cleared forests. Increasing productivity per hectare some 20% would be a good alternative to destroying forests. [BD]   

Unfortunately for the coffee world, increasing or even maintaining arabica production is a huge challenge, because arabica is genetically predisposed for extinction. Cultivated arabica plants have a genetic diversity of just 1.2%, compared with more than 20% for crops such as rice and soy. That makes it less able to adapt to changing conditions. It’s also fragile and susceptible to disease, including coffee leaf rust caused by fungus and pests such as the coffee borer beetle.

Hemileia vastatrix: Coffee leaf rust Credit: Smartse [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]

As stated in The Perfect Cup, a leaf rust epidemic that began around 2008 wiped out large areas of arabica production across Central America—including up to 40% of Colombia’s coffee crop. Colombian growers have had to replant 3 billion trees since 2008. In central American coffee countries and Columbia, coffee leaf rust (CLR) epidemics also caused serious crop losses in 2012-14. Breakdown of resistance to CLR has been reported in several countries, such as Brazil, Colombia, India, Thailand, and China. [Sources: The American Phytopathological Society, International Coffee Organization, London’s Royal Botanic Gardens]

Making the problem worse, climate change in coffee-growing areas is forecast to increase stress on arabica, making it more vulnerable to pests and disease. According to research published by London’s Royal Botanic Gardens last year in the journal Nature Plants [2017, DOI: 10.1038/nplants.2017.81], climate change will make up to 60% of the growing land in Ethiopia (a major supplier) unsuitable for coffee cultivation by the end of the century.  Across the world, arabica crops are already being “chased up the hillside” to cooler climes, says World Coffee Research (WCR), an organization set up in 2012 by coffee producers to protect and enhance supplies of quality coffee.  [BD]

Does this bad arabica coffee news have a cozy solution?

Alas, not a cozy one, but the threat does have three possible solutions, each of which has its supporters and detractors [BD]:

• Crossbreeding and improved farming practices

• Genetic engineering

• Pesticides or chemical treatments for protection

Coffee crossbreeding and improved farming practices

Coffee producers are working to protect arabica by cross breeding it with more resilient Coffea varieties and improving farming techniques to ensure arabica’s survival. [AS] Breeding methods depend mainly on the mating system and plant improvement goals. For the self-pollinating arabica, they include five main approaches [BD]:

• Selecting lines starting from available varieties

• Selecting pedigrees after crossing between varieties and often also back crossing

• Repeating multiple crosses and back crosses, selfing or clones

• Developing F1 hybrids between genetically different genotypes

• Creating hybrids between specific varieties and then backcrossing pedigree selection

Using these techniques, breeding efforts in several arabica coffee producing countries over the past 50-70 years have resulted in a long list of innovative and distinctive cultivars (plant variety that has been cultivated through selective breeding). These cultivars include F1 hybrids that can support sustainable production of high-quality arabica coffees.

World Coffee Research’s Christophe Montagnon, who has 28 years of experience in breeding coffee plants and has published more than 100 articles on the subject, believes combining crossbreeding and better farming practices is the best way of ensuring arabica’s survival. He’s also confident this approach will produce the great-tasting coffee consumers demand. WCR has the backing of more than 30 coffee-producing organizations.

Montagnon points to studies for support, including one by Jacques Avelino, a plant pathologist at the French agricultural research institute CIRAD. According to Avelino, who has been studying coffee cultivation for 30 years and is an adviser to WCR, farming practices that promote shading of arabica bushes can reduce rust and other diseases.

WCR’s Montagnon isn’t fond of using pesticides or genetic modification to combat arabica disease. “I don’t believe the solution is in pesticides,” he says. “I believe—and other scientists do—that we should be looking more at plant health.” Good use of fertilizer and farming practices such as promoting shade can be more efficient than the use of pesticides to protect rust-susceptible coffee plants, he argues.

Montagnon also maintains genetic modification isn’t an option. Or at least, he says the coffee world and story aren’t yet compatible with it. No genetically modified coffee is on sale anywhere in the world, and no major plan is under way to introduce it. That may be because genetically modified coffee would face social and regulatory challenges. Only big agricultural companies can afford the multi-million-dollar regulatory costs required to bring such a product to market.

Genetic engineering as a supplement to cross-breeding coffee plants

Many in the coffee industry don’t agree with Montagnon and the WCR about the potential for genetic engineering to solve the arabica problem. They believe future physical and biological stresses on coffee production from climate change will require more complex genetic solutions. In this view, breeders will have to combine classic selection methods with advanced genetic techniques to produce arabica coffee that can tolerate climate change and resist coffee leaf rust. These techniques will develop productive, disease- or pest-resistant, and generally resilient (hybrid) cultivars.

Scientists working on genetically modifying arabica think crossbreeding is slow and somewhat clumsy. “They are basically trying to breed a racehorse with a donkey. And it takes many, many years of backcrossing to get rid of the donkey,” says Brande Wulff, crop genetics project leader for the United Kingdom’s John Innes Centre. Genetic engineering is a quicker and more effective alternative to crossbreeding for heat tolerance and disease resistance, he argues. “With genetic modification, you can go to the wild relatives, identify resistance genes that matter, take them out with molecular tweezers, and stick them straight into your elite material to clinically combine the best of both worlds.”  [AS]

Lessons already learned from applying genetic engineering to other plant species should be transferable to arabica, Wulff suggests. “Resistance genes are like eyes that see the presence of the pathogen, and when they detect a pathogen, they can turn on defense mechanisms,” he says. Techniques such as CRISPR can change one or a few base pairs of DNA, but Wulff says traditional genetic engineering approaches are required to incorporate a full resistance gene, which is typically 30–100 DNA base pairs long.

A fungus might generate millions of spores, of which just one has a mutation that enables it to overcome a plant’s resistance. Two resistance genes would reduce the probability of the pathogen’s success to one in 1 trillion. Each new resistance gene can increase the odds against the pathogen’s success 1 million times. “If you introduce a stack of five genes, it should be durable for 100 years,” Wulff says.

Recent developments have made genetic engineering increasingly possible and accessible. The cost of cloning disease-resistance genes has plunged in the last few years to roughly $70,000 per gene. “So it is becoming much more affordable to clone these agronomically important genes,” Wulff says. Lower cost will enable researchers to take advantage of decreasing timelines for genetic studies, such as those at University of California, Davis.

UC-Davis researchers brought genetically modifying arabica coffee a step closer to reality in early 2017 when they released the plant’s genome sequence. “This new genome sequence for C. arabica contains information crucial for developing high-quality, disease-resistant coffee varieties that can adapt to the climate changes,” said UC Davis geneticist Juan Medrano, researcher on the sequencing effort.

Pesticides and other protective technologies

While genetic modification is under way, three of the world’s biggest agrochemical firms—BASF, Bayer, and Syngenta—say they have pesticides and other technologies that will protect arabica. Syngenta has introduced NuCoffee, a package of services that support best practices in coffee cultivation, including pesticide-use protocols. The approach is leading to much higher yields for coffee crops, says Daniel Bachner, a senior crop-protection executive at Syngenta in Brazil.

Meanwhile, BASF says it has begun offering coffee producers a variety of the mineral kaolin, which forms a dusty coating that puts off pests while also protecting against sunburn and keeping plant canopies cooler. Named Surround, the material doubles bean yields in coffee bushes, according to Peter Barrows, international business director for BASF subsidiary TKI.

BASF is also targeting leaf rust with an array of pesticides. “We are planning to launch a host of new products across all indications by the end of the decade,” BASF says. One example is Revysol, a triazole-based antifungal that the firm hopes will be its next blockbuster fungicide.

But scientists like Brande Wulff warn that farming improvements and crossbreeding, however well meaning, may not fight off climate change, pests, and disease. Consumers would then have to choose: switch to bitter robusta or wake up and smell the genetically modified coffee.

Resources:

African Coffee Production—Opportunities and Challenges, from Gro-Intelligence.com  Insights, August 8, 2018  [ACP]

Burleigh Dodds, Key challenges in breeding arabica coffee, from the book Achieving Sustainable Cultivation of Coffee, Coffee Talk, Science Publishing, October-November 2018, vol. 31, No. 7  [BD]

Alex Scott, Why the end of the world’s most popular coffee could be nigh Chemical & Engineering News, Volume 96 Issue 7 | pp. 26-27, Issue date: February 12, 2018  [AS]

Have a thought or more information about arabica coffee and its future? Let us know in the Comments section below.