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Ortiz, R. & Vuylsteke, D. Résumé L'hybridation et les manipulations ploodiques, c'est-a-dire les croisements interploidiques, ont permis d'obtenir les hybrides polyploides des plantains et des banaiers (Musa spp. L.). L'identification des hybrides prometteurs susceptibles de donner lieu aux cultivars necessite un essai au champ en vue d'evaluer leur performance agricole. Le potentiel de nouveaux hybrides selectionnes a ete evalue en les comparant a leurs races ancestrales triploides. Cette comparaison a ete effectuee dans deux essais composes respectivement de 25 et 30 genotypes. 26 tetraploide primaires, 7 triploides secondaires, 3 tetraploides secondaires et l'hybride tetraploide tertiaire ont ete evalues en meme temps que 7 races terrestres triploides et 3 ancetres diploides de 1993 a 1996. A partir de ce vaste essai en champ et de la liste des preferences des fruits, 7 hybrides prometteurs ont ete selectionnes en fonction des criteres suivants: la resistance souhaitee aux contraintes du milieu, les traits agronomiques acceptables et la qualite adequate des fruits. Les hybrides selectionnes etaient les tetraploides primaires noirs resistants au sigatoka et tolerants aux virus. Il s'agit de tetraploides TMPx 7152-2 (plantain),TMPx 7356-1 (plantain), TMBx 5295-1 (bananier feculent), et de triploides secondaires de Musa (TM3x) 14604-35, 15108-1, 15108-2, et 15108-6. Ce germoplasme ameliore a ete introduit au Nigeria pour des essais multilocalites et en Ouganda pour des essais locaux. A pres l'evaluation de leur stabilite et de leur adaptation au niveau local, on peut les promouvoir comme nouveaux cultivars dans les agroecozones specifiques. L'impact final de ces hybrides de Musa dans l'agriculture africaine sera mesure losque ce germoplasme deviendra une composante integrale de l'agriculture locale et des systemes alimentaires. Mots Clés Bananier, reproduction, heterosis, hybrides, plantain, polyploides

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Improved polyploid musa germplasm developed through ploidy manipulations Ortiz, R. & Vuylsteke, D. Abstract Plantain and banana (Musa spp. L.) polyploid hybrids have been obtained after interspecific hybridisation and ploidy manipulations (i.e., interploidy crosses). The identification of promising hybrids for cultivar release requires their field testing to assess agronomic performance. The potential of new polyploid hybrid selections was evaluated in comparison with their triploid ancestral landraces in two trials consisting of 25 and 30 genotypes, respectively. Twenty-six primary tetraploids, seven secondary triploids, three secondary tetraploids and one tertiary tetraploid hybrid were evaluated along with seven triploid landraces and three diploid ancestors from 1993 to 1996. Following this extensive on-station field testing and fruit taste panels, seven promising hybrids were selected based on their desirable attributes: desired resistance to biotic stresses, acceptable agronomic traits and adequate fruit quality. The selected hybrids were the black sigatoka-resistant and virus-tolerant primary tetraploids TMPx 7152-2 (plantain), TMPx 7356-1 (plantain), TMBx 5295-1 (starchy banana), and the secondary Musa triploids (TM3x) 14604-35, 15108-1, 15108-2, and 15108-6. This improved germplasm has been advanced for multilocational trials in Nigeria and for local testing in Uganda. After assessing their stability and local adaptation, they may be released as new cultivars in specific agroecozones. The final impact of these Musa hybrids in African agriculture will be measured when this new germplasm becomes an integral component of local farming and food systems. Keywords Banana, breeding, heterosis, hybrids, plantain, polyploidy

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