Preharvest Use of γ-Aminobutyric Acid (GABA) as an Innovative Treatment to Enhance Yield and Quality in Lemon Fruit

gamma-Aminobutyric acid (GABA) occurs naturally at a low concentration in fruits, but can be increased following several stress events, playing a physiological effect. Lemon trees were preharvest treated with GABA at three concentrations (10, 50, and 100 mM) during two consecutive seasons (2019-2020 and 2020-2021). Fruit growth (diameter) and crop yield (kg tree(-1) and number of fruits tree(-1)) and quality traits were evaluated at harvest. Results showed that treatments were effective at increasing lemon size (a 5% higher) and yield, especially for GABA at 100 mM, for the two assayed seasons. Thus, yield was increased between 13 and 18% with respect to the control trees for the two harvest dates. With respect to the quality traits, GABA treatments did not impact any negative effects on the quality attributes, since the total soluble solids (7-8 degrees Brix), total acidity (5-6 g 100 g(-1)), and fruit firmness (13-14 N mm(-1)) were similar to the control fruits. Therefore, GABA applied as preharvest treatment could be considered as a potent tool to enhance the yield of lemon fruits.

Automated summary

Preharvest treatment of lemon trees with GABA can increase fruit size and yield, especially at a concentration of 100 mM, resulting in a yield increase of 13% to 18%. GABA treatments do not have negative effects on the quality attributes of the fruits, as the total soluble solids, total acidity, and fruit firmness are similar to the control fruits.