DEVELOPMENT OF BREEDING PROGRAMMES IN EGGPLANT WITH DIFFERENT OBJECTIVES AND APPROACHES: THREE EXAMPLES OF USE OF PRIMARY GENEPOOL DIVERSITY

Diversity available in the eggplant (Solanum melongena L.) primary genepool can be used for developing new improved materials with better characteristics. We have initiated three breeding programmes in this crop aimed at different objectives: a) development of commercial hybrids for greenhouse cultivation (hybrids programme); b) improvement of the pickling ‘Almagro’ eggplant landrace (Almagro programme); and, c) introgression of traits of interest from the wild S. incanum into the genetic background of S. melongena (introgression lines programme). In the case of the hybrids programme we used as sources of variation a number of commercially successful hybrids of the black-type which presented a broad genetic diversity, as assessed with AFLP and SSR markers. These hybrids have been selfed for several generations and have been subjected to phenotypic selection for the traits of commercial interest. The lines obtained have a high degree of intra-line uniformity and we are obtaining experimental hybrids using as parents lines showing a good performance and a high genetic divergence. The Almagro programme is aimed at reducing the calyx prickliness of the original landrace. A selection programme has allowed selecting Almagro materials with lower prickliness. A backcross breeding programme using as donor parents a pickling eggplant with low prickliness and prickle-free fresh market eggplants has been initiated, in which selection using a participatory approach has been done for low prickliness and Almagro eggplant morphotype. At present, backcross materials up to the BC₃ generation have been obtained and are being tested in commercial fields of farmers. Finally, the introgression lines programme is aimed at developing a set of introgression lines of S. incanum in the genetic background of S. melongena by means of backcrossing and marker assisted selection. In this case, a genetic map has been obtained and selection is done so that the whole genome of S. incanum is represented in overlapping segments present in the materials used in the successive backcross generations. At present the BC₃ generation is being selected for further backcrossing. These three programmes are aimed at different objectives and are a typical example of different approaches, conventional and modern tools, for exploiting the diversity present in the primary genepool for the genetic improvement of a vegetable crop.