Researchers at the University of California, Davis (UC Davis) have released the first public genome sequence of Coffea arabica, the species providing 70% of global coffee production. Arabica coffee is a hybrid cross derived from robusta coffee (C. canephora) and the closely related C. eugenioides. As a result, C. arabica's complex genome has four sets of chromosomes, while most plants (and also humans) have only two chromosome sets.

The researchers collected genetic material from different tissues and developmental stages of 23 Geisha coffee trees in California. Geisha is known for its unique aromatic qualities, and is a high-value C. arabica variety that originated in the mountains of western Ethiopia. Plant material from UCG-17 Geisha was used for developing the C. arabica genome sequence.

UC Davis researchers used sequencing technology developed by Pacific Biosciences of Menlo Park, California. The researchers estimated that UCG-17 Geisha has a genome made up of 1.19 billion base pairs — about one-third that of the human genome. The study revealed an estimated 70,830 predicted genes. They sequenced samples from 22 other Geisha coffee trees to obtain a glimpse of the genetic variation within that variety and among 13 other C. arabica varieties. These are important in developing plants that can resist disease and cope with other environmental stresses.

For more details, read the news release from UC Davis.