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 complexinteractionsamongnutrientsduringuptakeanduseintheplantandits 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 isneeded to determinenew recommended leaf and fruit nutrient values suitable for both production and maintaining fruit quality during storage.