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This study was carried out to investigate cold injury and chemical compounds as related by the growth stage of immature fruit in loquat (Eriobotrya japonica Lindley cvs.) to provide basic data for minimizing cold injury. The larger fruits with diameter longer than 8.6㎜ received less cold injury than smaller ones, but, there was no difference in cold injury among cultvars in loquat orchard. Fruit clusters were exposed to three low temperature regimes (-2, -3 and -4℃) for varying duration (1, 2, and 4). The cold injury to immature fruits was 10% at -2℃. 30-40% at -3℃ and 95-100% at -4℃. Difference in cold injury between immature fruit was not noticed at -2℃ but the smaller fruits with diameter shorter than 9.5 ㎜ was significantly affected than the larger ones at -3℃. The conductivity rate of immature fruits exposd to low temperature increased as the fruit diameter decreased. A close correlation between conductivity rate and cold injury was shown. The freezing temperature of trait tissue checked with ´Mumok´ was -1.4, -1.5, -1.7. -1.7℃ and -1.8℃ in the immature friuts of 7.5, 8.0. 9.0, 10.2 mm and 11.2 mm in diameter, respectively, decreasing as the size of the fruits increased. The contents of reducing sugar, abscisic acid, cytokinins and unsaturated fatty acid increased while the contents of phosphorus, potassium and calcium decreased as the fruit size increased. Meanwhile, the contents of total sugar, starch, indoleacetic acid, nitrogen and magnesium did not vary significantly among the fruit size. The high contents of reducing sugars and unsaturated fatty acids were found to be related with decreased cold injury.
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