These research questions are focused on traits that address the main issues of banana cultivation, namely tolerance to biotic stresses, yield components and fruit quality.

Identify genetic determinants related to plant architecture and yield components

A breeding population of 2662 triploid banana hybrids, obtained by crossing 48 progenitors, was evaluated for agro-morphological traits at the CIRAD station in Guadeloupe. A decomposition of the genetic variance of the hybrids revealed the contributions of the components to the evaluated traits: the general combining ability (GCA) of the diploid and tetraploid parents, the specific combining ability of the parents (CSA) and the residual hybrid genetic component. Based on parent genotyping, the predictive ability of a genomic prediction model of average cross value was evaluated by cross-validation. The phenotyping data were adjusted to remove environmental factors and will be used to perform a GWAS analysis. A preliminary analysis has already shown a strong impact of chromosomal rearrangements in banana, generating large association blocks by co-segregation and loss of recombination, and substructuring in the populations preventing the detection of some associations.

Detection of QTLs related to fruit quality

Fruit quality is a major selection criterion in banana, as important as yield and pest resistance traits. To date, very little is known about the genetic determinism of this criterion. Therefore, we performed a QTL analysis for three major organoleptic quality criteria in banana: pH, firmness and pulp dry matter content. This study, carried out on a diploid segregating population, allowed us to identify the genomic regions involved and to detect several promising QTLs for the three traits, including three major QTLs allowing to consider marker-assisted selection for these traits and to improve selection schemes.

Impact of structural variations (translocations) on the detection of QTLs: the case of pH and the 1T7 translocation in banana

The search for QTLs related to fruit quality in banana in a diploid biparental population allowed the detection of a major QTL related to pH. This QTL is located on the LG1-7 linkage group and we have shown that the 1T7 haplotype, resulting from a reciprocal translocation present in the heterozygous state in one of the two parents, is associated with sweeter fruit at maturity. This structural heterozygosity appears to cause a lack of recombination in the region corresponding to chromosome 1 in this parent. Although the position of this QTL is not clear, this could be a favorable context for marker selection, as selection for this QTL could be made by following any chromosome 1-specific marker in progeny from this parent or from other parents with the same structure.

Key publications

Biabiany S, Araou E, Cormier F, Martin G, Carreel F, Hervouet C, Salmon F, Efile J-C, Lopez-Lauri F, D'Hont A, Léchaudel M, Ricci S (2022) Detection of dynamic QTLs for traits related to organoleptic quality during banana ripening. Scientia Horticulturae 293:110690

L.Toniutti, S.Rio, G.Martin, JY.Hoarau and F.Salmon (à paraître) Variation of morphological and yield traits in a banana (Musa acuminata) breeding program of triploid populations: lessons for selection procedures and criteria, Acta Horticulturae