Caratterizzazione molecolare del germoplasma di Solanum melongena

In this thesis are reported the results obtained by sequencing RAD of 76 accessions genotypes belonging to three cultivated eggplant species and wild species. The genomic DNA of a collection was characterized for the presence of single nucleotide polymorphisms (SNPs). Overall, 210 million fragments have been produced, that over 75,000 SNPs have been identified. Of all the polymorphic sites found in the 76 study individuals, 12,859 were present in coding sequences. Using the FastSTRUCTURE program, four main subgroups have been identified, including: (i) S. aethiopicum with its wild progenitor S. anguivi L.; (ii) S. melongena with it's progenitor S. insanum and the species S. incanum, S. lichtensteinii Willd. and S. linnneanum H. & P .; (iii) S. macrocarpon and his ancestor S. dasyphyllum Schumach & Thonn; (iv) native South American species S. sisymbrifolium Lam., S. torvum Sw. and S. elaegnifolium Cav. and some accessions not attributable to any of the 4 groups. By applying a hierarchical FastSTRUCTURE analysis on each subgroup, it has been found the membership about the accessions of S. campylacanthum, S. violaceum, S. lidii, S. vespertilio and S. tomentsum, and to genetically differentiate the three species in the sub-group 4. Data were also analyzed using Principal Coordinates Analysis (PCoA) which were conducted on both accessions and separately on individual groups. The PCoA analysis confirmed the results obtained previously by pointing out that it was not possible to identify a clear genetic differentiation between the cultivated species and their wild progenitors as well as between varietal and species varieties within the species. It has been confirmed that domesticated eggplant species, wild and American species all share a good part of the gene pool and that the genotype differences that characterize each species are a good source of useful genes for inbreeding. The large number of markers distributed across the genome could help facilitate the transfer of target regions that control genes for useful agronomic traits such as fruit quality and resistance to biotic and abiotic stresses, from species in question to species of cultivated aubergines.