Phenotypic and genotypic characterization of ‘Chinotto di Savona’ Citrus accession

For a long time ‘Chinotto di Savona’, a Citrus tree cultivated in Liguria region (northern Italy), has been considered a variety of Citrus myrtifolia (known with the Italian name ‘chinotto’). Nevertheless, molecular analysis to address its true genetic origin has been not performed yet. Fruits of ‘Chinotto di Savona’ are highly appreciated and often preferred to common chinotto for its superior organoleptic characteristics by food and beverage industries. This work reports a first morphological and genetic characterization of ‘Chinotto di Savona’ aiming at inferring its origin and main pomological traits. The main phenotypic characteristics of this Citrus accession were also evaluated and compared with those of the ‘common’ chinotto, considering leaves, shoots, fruits and seed morphology and juice composition. In addition, the colour evolution of fruit flavedo was monitored by reflectance spectroscopy. Molecular analyses were performed using SSR, AFLP and RNA-seq-derived markers, providing tools to discriminate ‘Chinotto di Savona’ from C. myrtifolia. A cytogenetic analysis was performed to assess ploidy of the Chinotto accessions. Findings confirm the genetic similarity of ‘Chinotto di Savona’ and C. myrtifolia, supporting the running hypothesis of their origin from somatic mutations of sour orange. Further analysis will be needed in order to fully understand whether they are independent somatic mutations of sour orange or if they originated from each other.