Effects of Mn Application into Soil and Adjustment of Soil pH on the Prevention of On-Tree Fruit Softening in Japanese Persimmon ‘Saijo’

Abstract

In order to prevent on-tree fruit softening in Japanese persimmon ‘Saijo’ (Diospyros kaki Thunb.), the effects of foliar application of MnSO₄ and soil application of manganese manure along with soil pH adjustment to acidity were investigated. Foliar application of MnSO₄ did not affect Mn concentration in the leaves, calyx and flesh. However, soil application of manganese after pH adjustment by sulfur powder application remarkably increased in the Mn concentration in the leaves, calyx, flesh and one-year-old shoots. In accordance with this increase, ethylene production in the fruit was decreased and the occurrence of fruit softening reduced. These results suggested that the maintenance of Mn concentration over 100 ppm by Mn manure application to the soil and pH reduction is necessary to prevent on-tree fruit softening of Japanese persimmon.