The Dextrose, Levulose, Sucrose, and Acid Content of the Juice from 39 Grape Clones

• The dextrose, levulose, sucrose and acid contents of the juice from 39 grape clones were determined to obtain information for use in breeding improved varieties. The 39 clones represented a survey of Vitis comprising native American species, American-type, French hybrid, and vinifera varieties. • Wide variation existed in the percentages of each sugar, in pH, titratable acidity, and buffer systems. • Sucrose was present in significant amounts only in clones which were derivatives of V. labrusa. • The levulose-dextrose ratio varied from 0.81 to 1.49; in only one clone was it less than 1.00. • The per cent of acid ranged from 0.35 to 4.74; the pH from 2.69 to 4.05. • The desirability of the standardization of sampling, extraction, and analytical methods in order that valid comparisons may be made between the results of various investigations is pointed out. • Certain aspects of the potential use of the information from these data in the development of improved grape varieties is presented.