Evaluation and selection of BC1 - BC2 - and BC3 genotypes derived from interspecific hybridization Solanum tuberosum - S. commersonii [Calabria]
2002
Carputo, D. | Ercolano, M.R. | Frusciante, L. | Iovene, M. | Parisi, M. | Sebastiano,A. | Monti, L. | Marzi, V. (Naples Univ., Portici (Italy). Dipartimento di Scienze Agronomiche e Genetica Vegetale) | Barone, A. (Consiglio Nazionale delle Ricerche, Naples (Italy). Istituto per il Miglioramento Genetico delle Piante da Orto e da Fiore)
To overcome the sexual barriers which hamper the transmission of noteworthy traits from the wild species Solanum commersonii to the cultivated potato S. tuberosum, a breeding scheme based on ploidy bridges and repeated backcrosses was carried out. Triploid F1 hybrids and near-pentaploid BC1, near-tetraploid BC2 and tetraploid BC3 progenies were generated. The morphological characterization of these progenies provided evidence that for most of traits analyzed the tuberosum phenotype was recovered. Only for a few traits, such as stolon length, the prevalent phenotype was still the wild one. The hybrid generations were evaluated for freezing resistance, capacity to cold acclimate and resistance to tuber soft rot by Erwinia carotovora. F1 hybrids were those with the highest freezing resistance and capacity to cold acclimate. However, interesting genotypes, especially in terms of capacity to acclimate, were found also in the BC1 and BC2. As for the resistance to tuber soft rot, resistant genotypes were selected in both the analyzed generation (18 in BC2 and 4 in BC3). The identification of RAPD and AFLP commersonii-specific molecular markers allowed to estimate the percentage of wild genome still present in the hybrids of each generation. This made it possible to perform a negative assisted selection, which led to the identification of 4 BC3 genotypes combining useful traits from S. commersonii with a wild genome content 20%.
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