Characteristics of ‘Pompia’ a natural citrus hybrid cultivated in Sardinia

The 'Pompia' is a probable citrus natural hybrid sporadically growing in the “Baronia” area (East Sardinia,Italy). The origin and taxonomic classification of this Citrus taxon is unknown. The fruit shows a yellow-amberflavedo at maturity and large size (weight from 200 to 700 g), irregular shape, light-yellow pulp, and lowjuice content. The traditional use as food is limited to the thick albedo after removal of the flavedo tissueand of the acid, non-edible pulp, and candying. This research had as its objective a morphological study ofnine accessions selected from four orchards of 'Pompia' in order to sample the observed variability of trees,shoots, leaves, and fruits. The results of morphological determinations showed a high similarity of 'Pompia' samples to lemon and citron species for thorns, fruit size and colour. The presence of small petiole wingletswas observed only on one accession. AFLP, RAPD, and SCAR analysis allowed the comparison of 'Pompia' with seven Citrus species: citron, lemon, pummelo, grapefruit, bitter orange, and mandarin. The analysis withmolecular markers demonstrated a close genetic relationship among 'Pompia', lemon, and citron. Moreover,the elaboration of the phenotypic and molecular analysis allowed evidencing a high level of similarity of thenine 'Pompia' accessions. Seven of them probably genetically correspond to the same clone.