Uncovering Coffee Beans' Genes

By Marcia Wood

New, gourmet coffees might result from investigations by researchers in Hawaii. Agricultural Research Service scientists at the U.S. Pacific Basin Agricultural Research Center and their Hawaii Agriculture Research Center colleagues are discovering more about the genetic makeup of this popular tropical crop. Their studies should benefit coffee lovers as well as coffee growers. Both research centers are located in Aiea, just outside of Honolulu.

One of the scientists' goals is to ensure that coffee's genetic diversity, or gene pool, is preserved for the future. That's because as-yet-unknown genes in today's popular commercial coffee varieties or in their wild, uncultivated relatives might hold the key to delicious new coffees for tomorrow.

The researchers examined coffee's genetic material, or DNA, to look for similarities and differences. Any dissimilarities among the species could be important. They could reveal interesting genes, such as ones that make some plants hardier or more disease resistant, or make their beans more flavorful.

The researchers analyzed Coffea arabica and C. canephora, the two most widely grown coffees in the world, and C. liberica, grown commercially in the Philippines as well as in parts of Africa. C. arabica was about 50 percent different from C. canephora and C. liberica. These differences may explain why these species vary in their resistance to pests, for example, or thrive at disparate elevations. Of the five C. arabica varieties studied, Catimor and Mokka Hybrid differed the most from each other--information that could eventually result in a better cup of coffee.

These studies are the most comprehensive genetic analyses to date of cultivated C. arabica coffees and the first to use a sophisticated laboratory technique called AFLP (amplified fragment length polymorphism). The scientists' findings were reported earlier in the journal Theoretical and Applied Genetics.

Read more about the research in the June issue of Agricultural Research magazine.