Development of cracks in early-harvested persimmon cultivar and their reduction by preharvest treatments

Diospyros Kaki Cv (Qiyuezao) 117 is an early ripening persimmon cultivar, ready to be harvested in August. One of the pitfalls of this cultivar is the development of cracks on its surface. These cracks turn brown after astringency removal, preventing the commercialisation of this cultivar. Pre-harvest treatment with Superlon™ (containing benzyl adenine (BA) + gibberellic acid (GA₄₊₇) at 40 mg/L of each) or Turbo™ (containing Thidiazuron (TDZ) at 5 mg/L) reduced cracks of different maturity fruit (green, green orange, and orange fruit) at harvest and following 5 days of astringency removal. Cracks remained low in the Plant growth regulators (PGRs)-treated fruit also following three months of storage. The PGRs treatments also reduced damage and Alternaria infection, developed during storage. Although fruit lost their firmness during storage, the PGRs-treated fruit remained firmer. Both PGRs treatments increased the number of cells in the peel. Thidiazuron was as effective as BA+GA₄₊₇ treatment at eight times lower concentration of each of the compounds. Hence, in-orchard TDZ treatment can be used to reduce persimmon cracks.