Effects of Foliar Spraying of Potassium and Sodium on Quality and Shelf Life of Kiwifruits

  Objective  Effects of foliar spraying potassium and sodium solution on quality and shelf life of Kiwifruits were studied.

  Method  Eight-year-old Actinidia deliciosa 'Guichang' plants under the conventional cultivation and management were sprayed separately with 9 different concentrations and combinations of potassium dihydrogen phosphate (PDP) and sodium chloride (SC) solutions. Quality of the kiwifruits at harvest and changes during storage in laboratory were evaluated.

  Result  The quality of kiwifruits under treatments improved at first as the PDP and/or SC concentration increased but declined when higher concentrations were applied after a peak on quality enhancement was reached. And, the quality improvement was greater when both PDP and SC were applied in combination. Among the treatments, the 0.2% PDP/0.1% SC combination yielded the most significant enhancement on fruit quality with the highest glycolate-to-acid ratio of 14.54, vitamin C content of 128.13 mg·hg⁻¹, fruit shape index of 1.65, and individual fruit weight of 76.07 g. The presence of 0.2% PDP significantly reduced the occurrence of soft and rotten fruits during storage prolonging the shelf life of the kiwifruits.

  Conclusion  Spraying the kiwifruit plants with a water solution of 0.2% PDP and 0.1% SC improved the quality, delayed the nutrient decline, postponed the soluble sugar peak, and extended the shelf life of the fruits.