Colombian Leaf Rust Resistant Coffee

The story of Colombian leaf rust resistant coffee is inspiring. Leaf rust is a fungal disease that has devastated coffee plantations as far back as the mid to late 19 th century. Those with an interest in history may know that Sri Lanka (old Ceylon) used to be a coffee producer until the leaf rust wiped out all production after which the nation switched to growing tea. The coffee leaf rust spread from the East Indies to South Asia and Africa and eventually to the new world. Today a plague of coffee leaf rust threatens the livelihoods of coffee growers and workers throughout Central America. Fortunately for the coffee producing nation of Colombia, the workers at the Cenicafé have found a cure. Cenicafé is a research organization funded by the Colombian Coffee Growers Federation – the folks who bring you Juan Valdez coffee . In the early 1970’s coffee leaf rust was found in the Americas. In the early 1980’s Cenicafé started work on producing a Colombian leaf rust resistant coffee. The Colombian leaf rust resistant coffee comes in two varieties, Colombian and Castillo. The first is a cross between an old Colombian variety, Caturra, and a rust-resistant strain from Southeast Asia, the Timor hybrid. Castillo is an offshoot of further cross breeding of the first Colombian leaf rust resistant coffee strain. Replanting with Colombian leaf rust resistant coffee in Colombia has reduced the incidence of leaf rust from 40% to 5% from 2011 to 2013.

Avoid, Treating, and Curing Leaf Rust

Some time back we wrote about how leaf rust kills organic coffee crops . The concern for organic coffee growers is that when the disease has progressed too far there are only two choices. One is to spray everything sight with fungicides and the other is to dig out all of the plants, spray, wait, and replant. It is sad that the move to sun resistant coffee strains and dense planting has tended to make coffee leaf rust more prevalent. Warmer temperatures facilitate the growth of leaf rust, and so does crowding the plants. Growing plants in the shade inhibits coffee leaf rust because temperatures are lower and because fungi that grow on coffee plants in the shade tend to inhibit the growth of coffee leaf rust. A grower who wants to produce healthy organic coffee can grow his coffee in the shade and he can invest, bit by bit, in introducing Colombian rust resistant coffee strains, and others as they become available. But, for those growers who are currently hit the worst, there will typically be a three year wait before new plants reach maturity and start producing coffee.

What Is the Gene?

What is the gene or what are the combinations of genes that make the Timor variety from Southeast Asia resistant to coffee leaf rust? Is it possible to find the gene and insert it into the chromosomes of high quality Arabica coffees? This approach would likely result in a cure of the leaf rust problem even more so than the breeding efforts that have produced Colombian leaf rust resistant coffee strains. But, will the organic coffee drinking community drink a coffee that has been genetically modified? This is a question for later times and later articles.

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