Banana genetics and breeding (GABA)
Research axes and results
Last update: 13 February 2023
Understanding the structure and evolution of genomes at different scales
Vegetative propagation has allowed the fixation of complex, often sterile genomic structures resulting from rare sexual events such as inter-(sub)specific crosses or polyploidization. An essential part of the phenotypic variability was then selected by farmers during successive cycles of vegetative propagation. In parallel, interspecificity has favored the activation of transposable elements and viral sequences integrated in the genomes. The study of the molecular mechanisms at the origin of this asexually generated variability and the impact of the integrated viral sequences are part of our research priorities.
Understanding trait architecture and phenotype development
Interspecificity, polyploidy and high levels of genetic and structural heterozygosity complicate the structuring of mobilizable diversity, gene expression and the analysis of the determinants of phenotypic variability and its genetic architecture. This biological context raises original research questions, which are studied for targeted traits: resistance to certain diseases, plant architecture, yield components and fruit quality. The search for genome zones involved in the regulation of these different types of traits (QTLs), and for complementarity between haplotypes, is carried out in parallel by targeted (segregating populations) and genome-wide (GWAS) approaches, depending on the criteria considered.
Developing breeding strategies by reconstruction of major ideotypes: Dessert bananas
Today's cultivated banana plants, whether diploid or triploid, are the result of a long process of crossing and domestication of wild species and subspecies of the genus Musa. However, triploidy is considered the best target for breeding improved banana varieties, as triploidy gives a selective advantage over other ploidy levels. Cross breeding conducted at CIRAD aims to create triploid hybrids directly from diploid germplasm. This approach, known as ‘reconstructive breeding’, is based on the search for the best combining abilities of two diploids, one of which, doubled by colchicine treatment, is a diplo-gamet donor. This original approach aims to combine the favorable traits contributed by the two parents and to maximize heterozygosity in triploid progenies.
Selecting novel banana varieties for domestic and export markets: Dessert bananas
The aim of our work on dessert banana is to select triploid varieties that are resistant to fungal diseases (cercosporiosis and fusariosis), that are well adapted to agronomic constraints and that meet strong fruit quality requirements, while preserving or even improving productivity and product adaptation to the different commodity chains. The selection and validation of varieties are conducted on the basis of a participatory approach, in partnership with the actors of research and development and the commodity chains, at the national and international levels.
Developing breeding strategies by reconstruction of major ideotypes: Plantain and other cooking bananas
The varietal diversity present in cooking bananas - and plantains in particular - is based on a reduced interspecific genetic background (AAB) and specific genomic structures, including the presence of infectious viral sequences integrated into the B genome (eBSV). Our breeding strategies, developed mainly in partnership with Cameroon (CARBAP/IRAD), seek to conserve or reproduce these genetic structures as best as possible, based on phylogenetically related genetic resources. To this end, two approaches are being developed in parallel: i) the use of diploid or tetraploid progenitors related to plantain and ABB cultivars that are close to this type; ii) the search for the best combining abilities between two diploids derived from plantain, one of which, doubled by a colchicine treatment, is a diplo-gamete donor.
Selecting novel banana varieties for domestic and export markets: Plantain and other cooking bananas
Our varietal innovation work aims to broaden the varietal offer by selecting new triploid genotypes resistant to the main pests and diseases, while preserving or improving as much as possible the organoleptic and technological qualities of traditional cultivars appreciated by local consumers. However, clonal selection is also taken into account in order to valorize the great natural diversity collected in the Congo Basin, a secondary diversification area for the plantain group. The selection process is based on participatory systems consisting of several networks of plots managed by planters with the involvement of various categories of stakeholders in order to facilitate the adoption of innovations.
Last update: 13 February 2023