Phenolic compounds in berries and flowers of a natural hybrid between bilberry and lingonberry (Vaccinium × intermedium Ruthe)

Hybridization between species plays an important role in the evolution of secondary metabolites and in the formation of combinations of existing secondary metabolites in plants. We have investigated the content of phenolic compounds in berries and flowers of Vaccinium×intermedium Ruthe, which is a rare natural hybrid between bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.). The berries and flowers of the hybrid showed characteristics inherited from both parent species in the distribution and contents of phenolic compounds. Bilberry is known as one of the richest sources of anthocyanins and to have a profile of 15 major forms combining cyanidin, delphinidin, petunidin, peonidin and malvidin with galactose, glucose and arabinose. Lingonberry contains only cyanidin glycosides. Hybrid berries contained all bilberry anthocyanins with pronounced cyanidin content. With regard to proanthocyanidins and flavonol glycosides, the hybrid inherited diverse profiles combining those of both parental species. The distribution of hydroxycinnamic acids was quite uniform in all studied berries. Of the identified compounds, 30 were detected in lingonberry, 46 in bilberry, 53 in hybrid berries and 38 in hybrid flowers. Hence, compared with the parent species, hybrid berries possess a more diverse profile of phenolic compounds and, therefore, can offer interesting material for breeding purposes.