Genetic diversity of some surviving on-farm Italian common bean (Phaseolus vulgaris L.) landraces

This study was undertaken to estimate the level of variation among and within thirty-three local populations belonging to seven Italian common bean landraces, by analysing the polymorphism of seed storage proteins, SSR and AFLP molecular markers. The nutritional seed quality of the studied landraces was also investigated. Results showed that the analysed landraces retain a considerable level of heterogeneity. Use of both biochemical and molecular approaches provided a picture of the genetic diversity of each landrace. 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. 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.