Cucurbit Genetics Cooperative Report 10:9 (article 8) 1987

Genetic Variation in Soluble Solids of Cucumber Fruit

R. W. Robinson

Department of Horticultural Sciences, New York State Agricultural Experiment Station, Geneva, NY 14456

High soluble solids of cucumber fruit can be detrimental for pickling, due to bloating (1), but may benefit flavor of slicing cucumbers. Genetic variation exists in cucumber for fruit soluble solids, though to a less extent than in some other vegetables, including muskmelon, winter squash, and tomato. McCreight, Lower, and Pharr (3) reported variation in reducing sugar content of 30 cucumber varieties and introductions. McCombs, Sox, and Lower (2) found significant differences in both reducing sugars and soluble solids content of five pickling varieties, but little variation in soluble solids of the more than 200 introductions and 50 varieties tested.

Juice was expressed from thawed transverse slices from the center of uniform sized fruit of 246 varieties and introductions of cucumber, and soluble solids was evaluated with a hand refractometer. Soluble solids content ranged from 3.0 to 5.2%. Entries with the lowest soluble solids content included PI 175686, PI 257486, PI 264668, and PI 283902.

The variety 'Lemon', despite its low yield, odd fruit shape and color, late maturity, and disease susceptibility, is popular with some home gardeners because they prefer its flavor. Interestingly, its fruit were higher in soluble solids than any other variety or introduction tested. 'Crystal Apple', which is similar to and is probably related to 'Lemon', was also high in soluble solids. The possible beneficial effect of high soluble solids on flavor, and the effect of the m gene of 'Lemon' and 'Crystal Apple' on fruit:vine ratio and fruit soluble solids, deserves further investigation.

Fruit pH of 225 introductions and varieties varied from 5.9 (for PI 175697) to 6.9 (for PI 275411 and 'Crystal Apple'), with 95% of the entries having pH of 6.0-6.6.

Literature Cited

1. Etchells, J. L., A. F. Borg, and T. A. Bell. 1968. Bloater formation by gas-forming lactic acid bacteria in cucumber fermentations. Appl. Microbiol. 16:1029-1035.
2. McCombs, C. L., H. N. Sox, and R. L. Lower. 1976. Sugar and dry matter content of cucumber fruits. HortScience 11:245-247.
3. McCreight, J. D., R. L. Lower, and D. M. Pharr. 1978. Measurement and variation of sugar concentration of pickling cucumbers. J. Amer. Soc. Hort. Sci. 103:145-147.