Burger, Y., Department of Vegetable Crops, Agricultural Research Organization, Newe ya'Ar Research Center, P. O. Box 1021, Ramat Yishay 30-095, Israel
Shen, S., Department of Vegetable Crops, Agricultural Research Organization, Volcani Center, P. O. Box 6, Bet Dagan 50-250, Israel
Petreikov, M., Department of Vegetable Crops, Agricultural Research Organization, Volcani Center, P. O. Box 6, Bet Dagan 50-250, Israel
Schaffer, A.A., Department of Vegetable Crops, Agricultural Research Organization, Volcani Center, P. O. Box 6, Bet Dagan 50-250, Israel

Sugar content is of primary importance in determining the quality of melon fruit. Levels of the three major soluble sugars, sucrose, glucose and fructose, were measured in populations of melon fruits that exhibited a broad range of total sugar levels. These included melons from commercial crops, from an experiment comparing the effects of low (12°C) and high (18°C) night temperature on fruit development, from low- and high-sugar-accumulating accessions throughout development, and from segregating populations derived from crossing low- and high-sugar accessions. In all cases, variation in sucrose content, but not hexose content, accounted for practically all the variation in total sugar content. These results point to the important role of sucrose and hence sucrose metabolism in determining sugar content and quality in melon fruit.