The kind of sugar and the availability of ethyl alcohol and their differences among cultivars were determined for oriental melon (Cucumis melo L.). Nine cultivars, `Gaeeuncheon´, `Euncheon (sin)´, `Cheongsagwa´, `Seonghwan´, `Keumseon´, `New Melon´, `Shipboard Melon´, `Wolgwa´ and `Josaeng-Hwanghyang´ were grown for this study. The results are as follows:
1. Three different sugars (sucrose, glucose, fructose) were measured in only `Josaeng-Hwanghyang´, `Wolgwa´, and `Shipboard Melon´. Four kinds of sugars (sucrose, glucose, fructose, and galactose) were contained in four cultivars of `Cheongsagwa´, `Gaeeuncheon´, `Keumseon´, and `New Melon´. Glucose, fructose, and galactose were available only in `Seonghwan´ while galactose was found in small amount in all cultivars grown for the study. Only in the cultivar `Euncheon (sin)´ glucose and fructose occurred simultaneously. `Euncheon (sin)´ was sweeter than other varieties.
2. Ethyl alcohol was detected in the cultivars, `Josaeng-Hwanghyang´, `Euncheon (sin)´, and `Keumseon´ at the late stage of fruit plumpness.
3. At the initial time of sugar accumulation sucrose appeared at low concentration 40 days after flowering while the concentrations of both glucose and fructose increased as the growth proceeded for `Gaeeuncheon´. In `Josaeng-Hwanghyang,´ `Cheongsagwa,´ and `Keumseon´ sucrose increased at the late stage and glucose and fructose gradually increased from the early stage to the age of 35 to 40 days and afterwards reduced.
Similar tendency of the accumulation of glucose and fructose was shown in `Euncheon (sin)´ and `Seonghwan´. The accumulation patterns of `New Melon´ and `Shipboard Melon´ were identical to those of the cultivars previously described for glucose and fructose. But only sucrose appeared to increase rapidly from 25 days after flowering to the late stage.
4. `Gaeeuncheon,´ `Shipboard Melon´, and `New Melon´ were the highest in total sugar and followed in the order of `Keumseon,´ `Josaeng-Hwanghyang´, `Cheongsagwa,´ `Euncheon (sin)´ and `Seonghwan´.
5. `Wolgwa´ contained glucose, fructose and sucrose. But the concentrations of total sugar were low for `Wolgwa´, and there was no sweetness of taste.
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