A comprehensive analysis of gibberellic acid and prohydrojasmon treatments for mitigating rind puffing and rind disorder of early-maturing cultivar of satsuma mandarin

Abstract

Increasing climatic temperatures and precipitation in the autumn may lead to increased injury and decay during extended storage of mandarin fruits. In this study, we examined the internal fruit quality, rind color, ultrastructure of the peel, inorganic composition of albedo, and flavonoid contents of the flavedo at harvest in the early-maturing cultivar satsuma mandarin ‘Miyagawa Wase.’ Fruits were treated with a mixture of gibberellic acid (GA; 25 mg L^− 1) and prohydrojasmon (PDJ; 100 mg L^− 1) denoted as (GP), only GA (25 mg L^− 1), and only PDJ (100 mg L^− 1) in August and September. Specific gravity and titratable acidity (TA) of the GA-treated fruits were higher than those of the non-GA-treated fruits (PDJ and control), while lower ratios of soluble solids content (SSC) and TA were observed. The GA-treated fruits’ L* (lightness), a* (bluish-green/red-purple hue component), b* (yellow-blue hue component), and C* (chroma) values were significantly lower than those of non-GA-treated fruits. In particular, a* value of GP (0.5) was significantly lower than that of control (24.6). The non-GP-treated fruits had higher epicuticular wax on the peel than GP-treated fruits. The distributions of N, P, and Mg in the GA-treated fruits were higher than those in non-GA-treated fruits. Nobiletin and tangeretin contents of the flavedo were the highest in the GP treatment, followed by the GA, PDJ, and control treatments. The occurrence of rind disorder after 20 d of storage was the lowest in GP, whereas PDJ and control treatments showed 18% over. These results indicate that the combined treatment with GA and PDJ has a more substantial effect than treatment with only GA or PDJ in controlling peel ripening at harvest and rind disorder after storage in satsuma mandarin fruits.