Résumé
RATIONALE. The use of the genetic diversity of Coffea arabica is a source of high genetic gains for adaptation and coffee quality. First, we evaluated Ethiopian wild accessions and coffee varieties for their diversity and adaptation to various conditions, namely Cerrados and Northern Parana in Brazil, French Guiana, and Cameroon, with special attention to drought and high temperatures. We analyzed biochemical contents related to cup quality. We crossed a selection of progenitors with local cultivars. The oldest hybrid progenies are now two years old. METHODS. To evaluate wild Ethiopian accessions and varieties we first used data obtained from collections established in various sites. From 2013 onwards, we crossed chosen plants with various dwarf cultivars. We established factorial hybrid trials at CPAC (Brazil, Cerrados), IAPAR (Parana), IRAD (Cameroon), and Cirad (French Guyana). Depending on the site, we use randomized design by tree, or by rows of 5 to 10 trees, with or without blocks. Stem diameter and height are the main criteria for vigor and compactness. RESULTS. The genetic gain of F1 hybrids is generally positive over dwarf cultivars for vigor and height and over Ethiopian mothers for vigor only, with a significant effect of the mother factor. Hence a possibility to select Ethiopian female parents for their General Combining Ability. CONCLUSIONS & PERSPECTIVES. We confirm the interest of Coffea arabica genetic resources to improve current cultivars in terms of vigor and of adaptation; maintaining plant compactness is possible. Cup quality will be checked. Further use of F 1 hybrids for breeding may use vegetative propagation or backcrosses to commercial varieties. GWAS studies are ongoing.