Three new somatic hybrids, namely an allotetraploid hybrid and two cybrids (2n and 4n), have been obtained by protoplast fusion of 'Valencia' sweet orange ( Citrus sinensis L. Osbeck) + 'Femminello' lemon ( C. limon L. Burm.). The chemical composition of the essential oils of the hybrids and their parents has been studied by gas chromatography (GC) combined with a flame ionisation detector (FID) and a mass spectrometry (MS). In all, 87 components were fully characterised and grouped in four classes (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes, and others) for an easier comparison of all oils. A statistical treatment by linear discriminant analysis of the compositional data from GC analyses was also carried out. The allotetraploid hybrid and both cybrids show an intermediate essential oil profile with respect to those of both parents. The contribution of 'Femminello' lemon parent is in all cases predominant in the production of the volatile profiles of the new hybrids; however, different behaviour in the peel essential accumulation between the allotetrapolid hybrid and the two cybrids is observed.
