Influence of foliar application of phenylalanine and urea at two doses to vineyards on grape volatile composition and amino acids content

The aim was to study the effect of phenylalanine (Phe) and urea (Ur) foliar applications to vines at two dosages on grape volatile and amino acid content. Results showed that the foliar application of both dosages of phenylalanine and the highest dose of Ur favored the synthesis of the aromatic positive compounds, decreasing the presence of C6 compounds in the grapes. Total amino acid content was not modified by the treatments. The treatment that most affected the concentration of amino acids was the lowest dose of Ur, increasing the content of seven amino acids. Phe applications increased the concentration of this amino acid. Therefore, foliar treatments with Phe and Ur were a suitable tool to improve grape volatile composition without affecting grape total nitrogen content.