Varietal Differences in Susceptibility to Early or High Temperature-induced Watercore in Apples

Abstract

To determine the susceptibility to early or high temperature-induced watercore, seasonal changes in the incidence and intensity of watercore, ethylene evolution, and sorbitol content in 4 apple (Malus pumila Mill. var. domestica Schneid.) cultivars grown at Matsuyama were investigated. Mean air temperature was above 25°C from early July to mid-September. ‘Himekami’ and ‘Shinsekai’ apples started to develop watercore from mid- and early August, respectively, before the onset of ethylene production. The incidence and intensity of watercore in ‘Orin’ apples increased from mid-July to early September, followed by a decrease through late October, whereas no watercore was observed until early November in ‘Fuji’. In conclusion, ‘Himekami’ and ‘Shinsekai’ are regarded as moderately, and ‘Orin’ as highly susceptible to early or high temperature-induced watercore, whereas ‘Fuji’ is considered as being resistant. Significant correlations between sorbitol and early or high temperature-induced watercore were observed.