Somatic cybridization for Citrus: polyphenols distribution in juices and peel essential oil composition of a diploid cybrid from Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and sour orange (Citrus aurantium L.)

Somatic cybridization is a technique based on inducted or spontaneous fusion between nuclear genome of one parent and either the cytoplasmic genome of the other parent or a combination of both donors. This approach is considered a powerful biotechnological tool in plant improvement since it enables to obtain novel intergenomic recombinations that are impossible to achieve by conventional crosses. Twenty-five plants were regenerated following protoplast fusion of Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and sour orange (Citrus aurantium L.) and a new 2n cybrid has been identified (4 % of plants obtained). A complete phytochemical investigation of the new genotype and both parents was carried out analyzing the polyphenol content of juices by liquid-chromatography-ultraviolet-diode array detector-mass spectrometry and the peel essential oils using a combination of gas chromatography equipped with a flame ionization detector and a mass spectrometry. On the whole 10 flavonoids (7 flavanone and 3 flavones) and 4 hydroxycinnamic acids were detected and quantified, while 67 components were fully characterized and grouped into four classes (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes, and others) for an easier comparison of all oils. Comparing the new cybrid to both parents an increase of the monoterpene hydrocarbons and a corresponding decrease of oxygenated components were shown. The aim of the present work was to evaluate whether the genome rearrangements in the new cybrid, obtained through not conventional strategies, can produce superior traits and improved performance such as enhanced presence and quality of bioactive components.