본 연구는 복숭아 주요 품종의 발육단계별 과실 생장 및 당대사 특성을 밝히고, 품종별 당조성과 당대사 관련 효소 활성의 변화와 이들의 상관을 구명하여 복숭아 과실의 당대사 기작을 밝히고자 하였다. 수확시기가 다른 복숭아의 4가지 품종의 종횡경 비(L/D ratio), 전분함량과 산도는 시간의 경과에 따라서 감소하는 경향을 나타냈으며 이와는 반대로 당도와 총 수용성 당 함량은 수확기까지 계속 증가하는 경향을 나타냈다. 또한 생육 초기에 포도당과 과당이 높게 나타났으나 성숙기에 자당함량이 크게 증가하여 수확기의 중요한 당 조성 성분은 자당으로 나타났다. 복숭아 과실의 당 축적은 자당 합성효소와 자당 분해효소에 의하여 큰 영향을 받았으나 자당 인산화합성효소나 소르비톨 산화효소의 활성은 전 생육기간동안 전반적으로 낮은 활성을 나타냈다. 총 전분과 총 수용성 당은 부의 상관을 나타냈고, 당도와 총 수용성 당은 정의 상관을 나타냈다. 그러나 각 수용성 당과 당도의 상관은 품종에 따라서 다르게 나타나서 당도 증가에 직접적인 영향을 끼치는 수용성 당은 품종의 차이를 보였다.The purpose of this research was to assess the sugar accumulation and related enzyme activities of peach fruit during fruit development. Fruit growth and development patterns of ‘Kanoiwa Hakuto’ (an early maturing cultivar), ‘Nagazawa Hakuho’ (a medium maturing cultivar), ‘Yumyeong’ (a late maturing cultivar) and ‘Changhowon Hwangdo’ (a very late maturing cultivar) were similar. In all cultivars, soluble solid content (SSC) increased rapidly as the fruit matured. The contrast, titratable acidity increased gradually until pit hardening stage, and then decreased as the fruit matured. Total soluble sugar content in fruit increased with fruit maturation. The change was almost sigmoid and mainly due to the change in sucrose which was the predominant soluble sugar in mature fruits, although initially glucose and fructose were the predominant soluble sugars in immature stage. Activity of sucrose synthase (SS) was high in young fruit and decreased as the fruit matured. That of SS increased again to high level with fruit maturation in all cultivars. On the other hand, sucrose-phosphate synthase activity was low throughout fruit maturation. Thus SS might account for the most portion of sucrose synthesis. Acid invertase (AI) activity was high at the initial fruit growth, and decreased to low level at ripening. Since AI activity was high at the early developmental stage, content of reducing sugars such as glucose and fructose were higher than sucrose content. There was the negative correlation between total starch and total soluble sugar. Sucrose was positively correlated with SSC in all the cultivars, while glucose, fructose and sorbitol showed negative correlations with SSC.