Increasing Bioactive Phenolic Compounds in Grapes: Response of Six Monastrell Grape Clones to Benzothiadiazole and Methyl Jasmonate Treatments

Abstract

The application of different elicitors to plants has proved a useful technique for the improvement of their phenolic content. However, studies have shown that the exact response of plants to elicitors depends both on variety and clone. In the present study, two elicitors (benzothiadiazole and methyl jasmonate) were applied in a vineyard where a collection of the six selected clones of Monastrell grape variety were planted to determine whether any observed effect was clone-dependent. The analysis of anthocyanins, flavonols, stilbenes, and seed and skin tannins showed that, in general, both elicitors increased the levels of phenolic compounds in the treated plants, although the extent of the response differed among different clones from the same variety. The positive effect of both benzothiadiazole and methyl jasmonate indicated that such treatments could be regarded as useful for improving grape and wine color while also increasing resistance to some pathogens. However, a preliminary exploratory field study should be carried out since differences in the response of the grapes to treatment might occur, depending on the clone.