Managing crop load on non-astringent persimmon (Diospyros kaki L.) grown in the sub-tropics

Abstract

Non-astringent persimmons have a natural tendency to set heavy crops of small fruit followed by light crops of large fruit. Markets discriminate against small fruit. In cooler climates, there are guidelines for removing (thinning) some fruitlets after flowering, a practice that significantly dampens swings in the crop cycle. However, no corresponding guidelines exist for the sub-tropics.
Over two years we applied four thinning treatments to 0, 5, 10 and 15 fruit per square metre of canopy surface area on Fuyu persimmons grown in south east Queensland. Tree performance was measured by fruit size and number, as well as by renewal growth and starch reserves in the following season. Trees with highest fruit loads (15 fruit/square metre) produced higher yields of small fruit in the first season followed by lower yield of larger fruit in the next season. They also had lower starch reserves at the beginning of the second season. In contrast, trees with the lowest loads (5 fruit/square metre) produced low yields of large fruit in the first season followed by higher yields of smaller fruit. They had higher starch reserves at the beginning of the second season.

Thus non-astringent persimmons in both the sub-tropics and cooler climates respond similarly to thinning, largely because crop load influences starch reserves in the tree in the following season. Our tentative recommendation is to thin Fuyu in the sub-tropics to 10 fruit per square metre.