Relationship between Air Temperature and Fruit Growth of ‘Maekawa Jiro’ Persimmon Grown in a Plastic House or Open Field

Abstract

Fruit growth of 'Maekawa Jiro' persimmon (Diospyros kaki Thunb.) grown in either a heated plastic house or open field was analyzed in relation to changes in air temperature during the period from 50 days after full bloom to fruit harvest. Air temperature in the plastic house was lower than that in the open field during fruit growth stage I, but the reverse conditions were observed thereafter. Both the plastic house-and field-grown fruits reached the end of the fruit growth stage I when the cumulative mean air temperature after full bloom reached 2,300°C・days, and the linear regression equations describing the relation between the daily increment of fruit diameter and the cumulative mean air temperature was quite similar. After fruit growth stage II, both plastic house-and field-grown fruits showed negative correlations between the daily increment of fruit diameter and mean air temperature, and the period when the growth of the plastic house-grown fruits was inhibited by high temperature was longer than that of the open field-grown fruits.