Cotton breeding in French-speaking Africa: Milestones and prospects

When cotton breeding programmes were first set up in French-speaking Africa in 1946, breeders were already taking the needs of different cotton stakeholders into account. The main breeding targets were productivity, resistance to pests and major cotton diseases, ginning outturn and fibre quality. The aim of this paper is to demonstrate how breeding has enhanced the performance of African cotton subsectors through presentation of results and experimental data from multilocation trials. Briefly, breeders have focused on Gossypium hirsutum cultivars, thus giving rise to plants with a relatively long growth cycle, that are vegetative and very floriferous, with delayed boll ripening (facilitating manual harvest), with a capacity to adapt to biotic and abiotic stress conditions, and with resistance to bacteriosis. Substantial gains were achieved in terms of productivity, ginning outturn and fibre quality (length, tenacity, fineness, and colorimetry). More than 90 cotton cultivars have been bred and released over a 60-year period. Genetic progress has, however, been limited in the last decade and African breeders will have to adopt new technologies to achieve further improvement in important traits. (Résumé d'auteur

Inventory and history of the CIRAD cotton (Gossypium spp.) germplasm collection

The CIRAD Cotton Germplasm Col­lection was founded in 1978 through the pooling of a number of working collections. It is one of the largest collec­tions in the world representing genetic variability in the genus Gossypium L. In 2005, it contained 3070 accessions, including 1696 cultivars and 1374 wild and ancestral types, covering five tetra­ploid species and seven diploid species. The two main cultivated cotton spe­cies, G. hirsutum L. and G. barbadense L., accounted for 68% and 15% of the accessions, respectively. The cultivars originated from around a hundred countries, and the ancestral species ac­cessions were collected during expedi­tions conducted between 1980 and 1988. Part of the ancestral type collection (894 accessions) was assembled with fund­ing from IBPGR (now Bioversity In­ternational), and these accessions were handed over to CIRAD for conserva­tion, assessment and release

Phenotypic evaluation of the CIRAD cotton germplasm collection

The CIRAD cotton germplasm collection was founded in 1978 and currently includes 3,070 accessions, of which 2,724 have been described for botanical, agronomic and technological traits. The collection includes 1,700 cultivated varieties and 1,370 wild or subspontaneous genotypes. This collection is used to increase genetic variability in breeding programs and marker-assisted selection program and for germplasm exchange between CIRAD and its collaborators. This poster presents the results of evaluations to identify accessions that could potentially be utilized to improve cotton cultivars of the cultivated species. The cultivar and wild-type accessions of these species were described and assessed during seed rejuvenation initiatives conducted under field conditions in various tropical countries. Results indicated that the genetic diversity of wild types of the four cultivated species could be used to improve some fibre characteristics in the cultivated species. Biotic and abiotic stress resistance will be highly important in the future and different methods to assess these features should thus be investigated. (Texte intégral