Résumé
The main tropical root, tuber and banana crops addressed within RTBfoods project are: cassava (Manihot esculenta), yam (Dioscorea spp.), sweetpotato (Ipomoea batatas), potato (Solanum tuberosum) and the East African Highland banana (Musa AAA group): Matooke. These crops share common biological traits: they are vegetatively propagated, flowering of varieties is erratic, ploidy levels are variable, they are allogamous and highly heterozygous. Breeding starts with the selection of parents based on their individual value. Hybrids are evaluated for a few traits and undesirable genotypes are discarded as soon as possible (Lebot, 2013). The national programs and CGIAR have been conducting RTB breeding programs for more than 30 years. A lot of progress has been made in the characterization of genetic resources, development of phenotyping tools, optimization of breeding schemes and lastly the integration of genomic tools in breeding programs. Genome Wide Association Studies and/or Genomic Selection are applied to all the crops concerned. Implementing of genetic and molecular approaches is contributing actively to the acceleration of the rate of genetic gains in the different on-going breeding projects. These efforts allowed the release of high yielding varieties and abiotic and/or biotic resistant ones. The quality is a trait, which is addressed from the beginning of the process or at the end when the breeding for the targeted traits was reached (Friedmann et al. 2018). Breeders use basic quality parameters associated with consumer preference (high dry matter, color, oxidation, and various attributes of the roots, tubers, or fruit) as selection criteria. The heritability of roots, tubers and banana quality traits valued by processors and end-users is little known or completely lacking for certain crops. Indeed, the means and subsequently the research investment on each crop, for quality and breeding, are not equal. We reviewed the statistics on the papers published on each crop by the international scientific community, recorded in the Web of Science. We applied the filter on the quality alone and in combination with the breeding filter. We found that research on quality in potatoes is far ahead with 3805 references recorded when the quality filter is applied alone and 273 when the quality and breeding filters are applied together. Cassava comes in second place (578, 57) followed by sweetpotato (154, 38) and yam (115, 10). For Matooke only 11 references were found without filter application. Although these statistics can be discussed and most likely are not as accurate, they reflect the scarcity of data and studies on breeding for the quality for these crops. Although, the work on RTB breeding for quality is not exhaustive and did not encompass all the quality traits, it can be very instructive. Within an institute, due to the turn-over, different researchers might have worked on this field. Data are stored but not shared or mined for the targeted traits. In universities and institutes, students have produced theses. The results have not been published in peer-reviewed papers but they are still of interest and could be used. In this document, each institute has gathered the information they have access to, to report the state of knowledge on the targeted crop. The objective of this review is to make an inventory of the previous activities on RTB breeding for quality, based on the papers published by the scientific community and on the activities conducted by research centers partners of the project. This review focuses on the breeding for product quality and is not intended to cover all breeding activities conducted within the different on-going projects. This review is a starting point, which will allow us to identify the gap analysis for each crop. Subsequently, within the RTBfoods projects, using the high throughput phenotyping (HTPP) methods developed, the breeding activities can be conducted in a way to fill up these gaps.