Fruit Phosphorous and Nitrogen Deficiencies Affect ‘Grand Pearl’ Nectarine Flesh Browning
Fruit flesh browning (FB) is a major component of cold storage disorders that limits fresh and fresh cut fruit consumption. Using fertigation, nutrient deficiencies were imposed on ‘Grand Pearl’ nectarines (Prunus persica var. nectarina) grown in sand culture for 8 years and postharvest flesh browning was studied over 2 years. Antioxidant activity, polyphenol oxidase activity, total phenolics, and fruit FB potential were evaluated. Nutrient deficiencies did not always result in leaf or fruit tissue deficiency, indicating complex interactions among nutrients during uptake and use in the plant and its fruit. Low phosphorus and nitrogen fruit concentrations were associated with biochemical browning reactions in fruit flesh at harvest and with fruit FB during storage, signs of a shorter market life and lower consumer quality. Currently recommended leaf and fruit nutrient critical values are based only on production and do not address postharvest quality. Further research is needed to determine new recommended leaf and fruit nutrient values suitable for both production and maintaining fruit quality during storage.