Phenolic fingerprinting and glumes image analysis as an effective approach for durum wheat landraces identification

In the last decade, encouraged by economic, social and nutritional reasons, the trend towards the rediscovery and reuse of durum wheat landraces moved on in Sicily. This growing attention in local wheat landraces made necessary to design new effective and objective identification methods that are able to distinguish landraces. Considering the difficulties coming from the genetic and morphological heterogeneity of a landrace, in this chapter a multidisciplinary approach for durum wheat landraces identification is proposed. Nine Sicilian wheat landraces were investigated from the genotypic and phenotypic point of view, studying their polyphenolic profile, and analyzing the glumes morpho-colorimetric traits, in search of similarities and/or differences. In particular, hydro-alcoholic extracts from whole wheat grains were analyzed by means of HPLC/ DAD and HPLC/ESI-MS, revealing 13 metabolites mainly belonging to the classes of hydroxycinnamic acids and flavones C-glycosides. The quantitative pattern of the 13 phenolic markers allowed to perfectly identify all the wheat samples, confirming a specific and genotype-dependent pattern of phenolics concentration. Moreover, computerized image analysis techniques were applied to compare the wheat samples on the basis of 138 quantitative morpho-colorimetric variables descriptive of glumes size, shape, color and texture, confirming the possibility to undoubtedly identify wheat samples belonging to local landraces.