Phosphorous and Nitrogen Fruit Deficiencies Affect 'Grand Pearl' Nectarine Fruit Browning

Fruit flesh browning (FB) is a major component of cold storage disorders that limit stone fruit market life. The effect of nutrient deficiencies imposed using fertigation on postharvest flesh browning of 'Grand Pearl' nectarines [Prunus persica cv. nectarina] was studied for two years. Nutrient deficiency treatments were imposed for eight years in sand culture and antioxidant activity, polyphenol oxidase activity, total phenolics, and fruit flesh browning potential were evaluated at the end of the of this period. Nutrient deficiencies did not always result in leaf or fruit tissue deficiency, indicating a complex interaction of nutrients during uptake and use in the plant and its fruit. Low P and N fruit concentrations were associated with biochemical browning reactions in fruit flesh at harvest and fruit flesh browning during storage, suggesting a shorter market life and lower consumer quality. Current recommended leaf and fruit nutrient critical values are based only on production measures and thus do not ensure postharvest quality. Further research is needed to determine new recommended leaf and fruit nutrient values suitable for both production and fruit quality during storage.