PRE-HARVEST APPLICATION OF SALICYLIC ACID MAINTAIN THE RIND TEXTURAL PROPERTIES AND REDUCE FRUIT ROT AND CHILLING INJURY OF SWEET ORANGE DURING COLD STORAGE

Trees of citrus cvs ‘Lane Late’ and ‘Valencia Late’ oranges were sprayed ten days before anticipated harvest with salicylic acid (SA) at different concentrations (2, 3, 4, 6, 8, 9 mM). Fruits were harvested and stored at 5°C for 93 days to investigate the effects of SA on fruit rot, chilling injury and quality relating parameters such as rind and fruit firmness as well as sugar and organic acid contents. Fruits were analyzed before storage and after 31,62 and 93 days of storage and found that SA at 8 mM and 9 mM reduced fruit rot from 16.93% to 6.06% and 12.78% to 5.12% in ‘Lane Late’ and ‘Valencia Late’, respectively. Chilling injury was significantly reduced at 8mM and 9mM treatments. Textural properties relating to rind puncture, rind tensile and fruit firmness forces showed that treated fruits were significantly firmer than those of control. Maintained contents of SSC, TA, individual sugars and organic acids in treated fruit with higher doses after 93 confirmed preliminary findings such as SA has anti-senescent effect. Our research suggests that pre-harvest spray of SA can be used effectively to minimize the postharvest/storage losses of sweet oranges cultivars.