First observations of graft combination on bergamot fruit quality, Femminello cultivar

Summary Introduction – The bergamot is cultivated along the Calabrian coast. It is grafted onto sour orange that is susceptible to Citrus Tristeza virus. Although no infections have been reported on this scion/rootstock combination, CTV is present in Calabria and it is well known that this rootstock is very susceptible to the virus. Furthermore, very few are the experimental works that have as object the food consumption of bergamot. The experiment was carried out to evaluate two alternative rootstocks to sour orange for bergamot, during the first years from planting, in the main cultivation area for bergamot essential oil production. The influence of rootstock was evaluated about bergamot fruit quality for fresh consumption, because the nutraceutical role of this citrus for food has been discovered in recent years. The quality of the essence was also evaluated concerning the most important molecules that characterize the bergamot essence, being linalyl acetate, linalool, and limonene. The yield was also evaluated. Materials and methods – The experiment was carried out to evaluate the influence of the alternative rootstock to sour orange on the quality of the bergamot for food consumption. The influence of rootstock on the fresh yield, and the yield and quality of the essential oil was also evaluated. The experiment was carried out during three years (2017/2019) in Reggio Calabria (Italy) on bergamot tree (Citrus bergamia Risso & Poiteau) cv. Femminello, grafted onto sour orange, Troyer citrange, and Volkamer lemon. At harvest, biometric measurements, yield per tree, organoleptic and nutraceutical parameters, gland counts, quality of essential oil, and yield of essential oil of the fruit were detected. Results and discussion – The main qualitative and nutraceutical parameters were similarly replacing sour orange with Volkamer lemon and Troyer citrange. About the production per plant and yield efficiency, the worst results were obtained with Troyer citrange. The better yield of essential oil per plant and a high quality of the essential oil were obtained with Volkamer lemon rootstock. Conclusion – Therefore, Volkamer lemon appears like an excellent alternative to sour orange.