The bean (Phaseolus spp.) landraces of the Lombardy Alps (Northern Italy): characterization and prospects for their valorization

The loss of agrobiodiversity is a world damage both in biological and cultural aspects. Although mountainous areas in Italy still preserve many traditional cultivars (landraces), they face increasing risk from genetic erosion and disappearance. This study focused on the identification and multidisciplinary characterization of 16 previously undocumented bean landraces (Phaseolus vulgaris and P. coccineus) from the Lombardy Alps (Italy) using genetic, morphological, nutritional and ecological approaches. Genetic analyses based on simple sequence repeat (SSR) markers revealed moderate but structured diversity among 18 bean genotypes, with 1–5 alleles per locus and polymorphism information content (PIC) values ranging from 0 to 0.772. The principal coordinate analysis (PCoA) explained 66.01% of total genetic variation and, together with the unweighted pair group method with arithmetic mean (UPGMA) clustering, clearly separated landraces from commercial controls and distinguished P. vulgaris from P. coccineus, highlighting high intra-specific variability likely linked to geographic origin and absence of formal breeding. In contrast, morphological outline analysis and nutritional profiling showed that each landrace possesses unique and distinctive traits without major intra-specific variation. All beans showed high levels of proteins (20–29%) and some accessions (pigmented seeds) had a good quantity of antioxidants and other functional compounds, reinforcing their value as nutritious and health-promoting products. Furthermore, the ecological assessment indicated a shared competitive/competitive-ruderal strategy while morphometric seed analysis explained 90.9% of total shape variation (LD1 = 60.5%; LD2 = 30.4%) and identified three main morphotypes (reniform, elliptic, roundish), without clustering consistent with species or genetic groups. The results underscore the remarkable intra-genus and intra-specific diversity within Phaseolus landraces suggesting that this variability is genetic, nutritional and phenotypic. Their cultivation (on farm conservation) and integration into local value chains could support sustainable development in marginal areas and bring new opportunities for mountain economies. Moreover, the data collected provide a scientific basis for the registration of these landraces in Italian and European agrobiodiversity registers, a key step for their protection and promotion.