TRADITIONAL BREEDING AND MODERN GENOMICS: A SUMMARY OF TOOLS AND DEVELOPMENTS TO EXPLOIT BIODIVERSITY FOR THE BENEFIT OF THE COFFEE AGROINDUSTRIAL CHAIN

Coffee provides daily pleasure for millions of people around the world and its exports represent a significant share of revenues to many developing nations. Production by smallholders and a diversified agroindustrial chain worldwide supports its social importance. The genetic makeup of individual cultivars influences all chain segments, from nurseries to consumers. Cultivar improvement relies heavily on genetics, breeding, germplasm conservation and its exploitation. Seventy percent of coffee traded in international markets is Coffea arabica (2n=4x=44 chromosomes), i.e., a segmental allotetraploid, 90% of which are self-reproducing highland species from Ethiopia. Coffea canephora accounts for the remaining 30% of international markets. It is a diploid (2n=2x=22) self-incompatible species native to tropical Africa, which thrives preferentially at lower altitudes in hotter climates. Coffea canephora, though sturdier and higher yielding, results in a less aromatic beverage. A coffee germplasm collection is maintained at Instituto Agronômico de Campinas (Brazil). Of 105 known diploid species including several self-incompatible Coffea-Psilanthus species, 19 are represented in this collection in addition to many F₁ and complex intra- and interspecific hybrids and derivatives, single gene mutants, chromosomal variants, breeding lines, segregant populations and 66 released cultivars. Conservation and exploitation of such broad diversity involves sexual and vegetative reproduction. Cropping efficiency is increasingly challenged by sustainability concerns and specific demands of differentiated and commodity markets. Desirable cultivar attributes encompass uniform ripening, short stature, resistance to major pests, consistent quality and unique cup flavors found in primary and secondary gene pools with variably introgressed C. arabica or C. canephora genomes. Comparative biology links coffee to tomato in Asterid I. As such, the intersection of existing coffee genetic diversity with the expanding understanding of the Solanaceae family through modern genomics (including ongoing tomato genome sequencing) offers the unprecedented opportunity to accelerate breeding and to incorporate useful traits into cultivars for the benefit of the entire agroindustrial coffee chain of production to consumption.