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Effects of limited supply of nutrient solution on fruit development and changes of soluble sugar contents of musk melon were evaluated in ash ball, perlite, and mixed substrate (perlite + ash ball; 6:4, v/v) culture. Forty days after anthesis, the nutrient solutions were supplied to plant with the amount of 0.4 L (high water stress), 0.8 L. (water stress), and 1.2 L (control), respectively. Fruit weight, length, diameter, and flesh thickness were better in the order as follows; perlite, mixed substrate, and ash ball. But no difference was found in flesh firmness and net formation among substrates. Soluble solid contents and total sugar contents of the fruit were higher in the order of ash ball $gt; mixed substrate ≥ perlite in the water stress treatment. In ash ball substrate, fruit weight was largest in control treatment and lowest in high water stress treatment, whereas the soluble solid contents of the fruit were highest in water stress treatment and decreased in high water stress treatment from 50 days after anthesis. The contents of sucrose, fructose, and glucose were higher in order of water stress $gt; control $gt; high water stress treatment. The ratio of sucrose in total sugar was higher in order of control $gt; water stress $gt; high water stress treatment, whereas the ratio of glucose and fructose in total sugar were higher in order of high water stress $gt; water stress $gt; control treatment. This fact demonstrated that the distribution rate of sucrose, glucose, and fructose of the fruit were different when the limited nutrient solution supplied. The sucrose/(fructose + glucose) content ratio was higher in the order of control $gt; water stress $gt; high water stress treatment, but fructose/glucose content ratio was not significantly different among all treatments.
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