Morphological, chemical and genetic characterization of Citrus monstruosa, an endemism of Sardinia

The taxonomy and phylogeny of the genus Citrus is rather complicated because of its interspecific sexual reproduction capacities, extended apomictic reproduction and high phenotypic variability. The hybridization might have played an important role in the development of cultivated species of Citrus.In Sardinia the notice of a peculiar citrus named Pompia (Citrus x monstruosa), was observed for the first time in 18th century. This cultivated citrus is limited to a restricted area of the island and its taxonomic classification is quite ambiguous and most often recognized as related to citron. The fruit pulp is not consumed but its pericarp is used to make candies and its essential oils appears to be suitable for cosmetic use and phytotherapy. The aim of the present work is to study the genetic origin and diversity of Pompia specimens collected in different areas of Sardinia and compare them with known Citrus species through genetic analysis and her morphological and chemical description. The genetics analysis highlights its hybrid origin, similar to lemon, resulting from a cross betweenC. aurantiumandC. medicawhere the citron was the pollinator. Moreover, our results have led to the characterization of the Pompia fruit phenotype and the profile of its essential oil. These results may be useful to increase the knowledge about the origin of this peculiar plant.