Seasonal Fluctuation of Freezing Tolerance and Soluble Sugar Content in Three Sweet Persimmon Cultivars

Sweet persimmon (Diospyros kaki Thunb.) exhibits insufficient freezing tolerance (FT) in comparison with other temperate fruit trees. Information about FT of sweet is scarce. In this study, was analyzed three persimmons cultivars, ‘Fuyu’, ‘Taishuu’, and ‘Romang’, using an electrolyte leakage method for two successive years (Year 1, November 2017 to April 2018; Year 2, 2018 2019). Current-year shoot samples from 8-year-old trees each cultivar were collected analyze experimental orchard (Pear Research Station, Naju, Korea). Average daily air temperatures increasingly declined 2017, reaching the minimum mid-January 2018. They then steadily increased until 1). Patterns average 2 similar those 1 except that they reached at end December cultivars constantly during cold acclimation (from January), whereas decreased deacclimation February April) both years. Shoot 2) most freezing-tolerant ‘Romang’ freezing-susceptible ‘Taishuu’ used soluble sugar analysis HPLC. total content highest started decrease January 2019 2019. Fructose glucose contents showed same pattern as sugar. Meanwhile, sucrose maltose detected minimally throughout whole period. These results indicated fluctuations sugar, fructose, paralleled (p < 0.001).