Conservazione "on-farm" di cultivar tradizionali di fagiolo: aspetti biochimici e molecolari.

The increasing request for typical products and the consequent widening of new marketing opportunities, as well as the possibility to obtain quality and origin marks, is offering new chances of survival to Italian landraces. The present study was undertaken to estimate the level of variation among and within thirty-one local populations belonging to six common bean landraces, by analysing the polymorphism of SSR and AFLP molecular markers. The nutritional seed quality of the studied landraces was also investigated. Cluster analyses based on Nei's genetic distances and Jaccard's similarity index as defined by SSR and AFLP markers, respectively, showed that all populations clustered into two groups corresponding to the Andean and the Mesoamerican gene pools. The diversity analysis revealed contrasting levels of variability depending on the landrace. The highest level of variation was evidenced for the white small-seeded landrace "Fagiolo del Purgatorio", whose populations were grouped in more than one subclusters. Knowledge of the genetic structure of a landrace is fundamental to elaborate strategies that, involving the local farmers, allow to improve and, at the same time, safeguard the genetic integrity of landrace genetic resources.

E' stato valutato il livello di variabilità presente in cultivar tradizionali di fagiolo attraverso il polimorfismo dei marcatori molecolari SSR e AFLP. Le analisi cluster basate sia sulle distanze genetiche di Nei, che sull'indice di similarità di Jaccard, hanno mostrato che tutte le popolazioni si raggruppano in due grossi gruppi corrispondenti ai gene pool Andino e Mesoamericano. Il più alto livello di diversità genetica e la sua più articolata strutturazione sono presenti nella cultivar Fagiolo del Purgatorio. Sono state analizzate alcune caratteristiche nutrizionali del seme come il contenuto in proteine totali e solforate e il livello degli inibitori delle proteasi.