The effect of pre-harvest salicylic acid and gibberellic acid applications on-tree storability in ‘Satsuma’ mandarins (Citrus unshiu Marc.)

Abstract

Objective: Satsuma mandarin (Citrus unshiu Marc.), an important export product for Türkiye, is kept on the tree until the beginning of January. This study aimed to determine the effects of single and co-application of salicylic acid (SA) and gibberellic acid (GA3) on the storability of Satsuma mandarin on trees. 
 Material and Methods: For this purpose, 20 ppm GA₃ two weeks before the color break period, 2 mM SA, and 1.5 ml/L Rezist at the color break period were applied alone and together to Satsuma mandarin fruit. Those without treatment were accepted controls. Various measurements and analyses were made in the samples taken at monthly intervals during storage on the tree. 
 Results: It was harvested in three periods at approximately one-month intervals from the beginning of November. The applications of SA or GA₃ alone or together limited the fruit drop rate during on-tree storage, the increase in the shell thickness, and the decrease in the specific gravity. Applications involving GA₃ delayed the coloration of fruits. The maturity index of the fruits treated with Resist and GA₃ in the first harvest was lower. 
 Conclusion: The results showed that the pre-harvest applications of Satsuma mandarin would have positive contributions to the storage of fruits on the tree until the beginning of January by preventing fruit drop, and delaying the peel and fruit aging.