Flavonol content and biometrical traits as a tool for the characterization of "Cipolla di Giarratana", a traditional Sicilian onion landrace

"Cipolla di Giarratana", a locally cultivated white onion landrace, is listed as an item in the 'List of Traditional Agro-food Products' of the Italian Department for Agriculture and itemized as 'slow food presidium' by the Slow Food Foundation. 10 local accessions were investigated for their biomorphological and biochemical characteristics in five experimental fields. High-performance liquid chromatography coupled with diode array detection and electron spray-mass spectrometry (HPLC/DAD/ESI-MS) was used to identify the phenolic profile and quantify phenolic content in bulbs: quercetin, quercetin 3,4' di-O-glucoside and quercetin 4'-O-glucoside were detected as major components. The 'Cipolla di Giarratana' landrace is characterized by a high bulb weight (436 g) and high diameter (11 cm). The total flavonols content ranged between 68 and 408 mg kg-1 bulb fresh weight in nine of the ten collected accessions The opportunity of considering flavonol patterns as chemotaxonomic descriptors in order to characterize onion germplasm is also discussed.