Developing a molecular identification assay of old landraces for the genetic authentication of typical agro-food products: The case study of the barley 'Agordino'

The orzo Agordino is a very old local variety of domesticated barley (Hordeum vulgare ssp. distichum L.) that is native to the Agordo District, Province of Belluno, and is widespread in the Veneto Region, Italy. Seeds of this landrace are widely used for the preparation of very famous dishes of the dolomitic culinary tradition such as barley soup, bakery products and local beer. Understanding the genetic diversity and identity of the Agordino barley landrace is a key step to establish conservation and valorisation strategies of this local variety and also to provide molecular traceability tools useful to ascertain the authenticity of its derivatives. The gene pool of the Agordino barley landrace was reconstructed using 60 phenotypically representative individual plants and its genotypic relationships with commercial varieties were investigated using 21 pure lines widely cultivated in the Veneto Region. For genomic DNA analysis, following an initial screening of 14 mapped microsatellite (SSR) loci, seven discriminant markers were selected on the basis of their genomic position across linkage groups and polymorphic marker alleles per locus. The genetic identity of the local barley landrace was determined by analysing all SSR markers in a single multi-locus PCR assay. Extent of genotypic variation within the Agordino barley landrace and the genotypic differentiation between the landrace individuals and the commercial varieties was determined. Then, as few as four highly informative SSR loci were selected and used to develop a molecular traceability system exploitable to verify the genetic authenticity of food products deriving from the Agordino landrace. This genetic authentication assay was validated using both DNA pools from individual Agordino barley plants and DNA samples from Agordino barley food products. On the whole, our data support the usefulness and robustness of this DNA-based diagnostic tool for the orzo Agordino identification, which could be rapidly and efficiently exploited to guarantee the authenticity of local varieties and the typicality of food products.