γ-Aminobutyric acid treatments of pomegranate trees increase crop yield and fruit quality at harvest

•γ-Aminobutyric (GABA) treatment of pomegranate trees increased crop yield.•Skin and aril colour of fruit were enhanced by GABA treatments.•GABA treatments led to increased anthocyanin and phenolic content in pomegranate arils.•Total soluble solids, total acidity or firmness were not affected by treatments.