Strategies for Robusta Coffee ( Coffea canephora ) Improvement as a New Crop in Colombia

Robusta coffee is mostly grown in Africa and Asia and parts of tropical America, but not yet in Colombia. The crop has potential in lowland areas of this traditional Arabica coffee producer. Compared to Arabicas grown in highland areas, the Robustas have more drought and heat tolerance. However, they differ in flavor and have higher caffeine levels. With natural resistance to some of the major pests and diseases of other coffees, such as rust and berry borers, they thrive under harsh conditions. The genetic improvement of Robusta coffee requires the understanding of its genetic resources and a good breeding strategy. This review discusses the traits of interest and selection criteria for breeding and recommends methods of varietal development for Robusta in Colombia. Most of the traits of importance in breeding are quantitative and of low or intermediate heritability. Robusta is an outcrossing species and can suffer from inbreeding depression, so mass and recurrent selection are used, followed by the clonal propagation of best plants. Colombia has limited germplasm only from the Congolese group, so the SG1/Conilon and SG2 genotypes should be introduced with quarantine. Issues to address include the timing of flowering, asynchronous fruit maturation, chemical composition and sensory quality, as well as bean size. Variability for abiotic stress tolerance exists in Robusta genotypes and needs further study. New methods of breeding include hybrid development and recurrent selection. Having adapted varieties of Robusta coffee should promote production in Colombia, as it has in regions of Brazil, and would complement Arabica coffee for this traditional and major producer.