Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu
Cucumbers are a popular crop grown throughout Delmarva for both fresh market (slicers, mini) and processing (pickles).
There are three flowering or fruiting types. Monecious cucumbers have both male and female flowers on the same vine with a higher number of male flowers compared to female flowers. Gynoecious cucumbers have mostly female flowers and are sold as a blend with 5-15% monecious pollenizers included to provide adequate pollen. Because most plants produce female flowers, they are more productive. Most of our acreage are gynoecious hybrids. Honeybees, squash bees, bumblebees and other wild bees are important for proper cucumber pollination and fruit set for monecious and gynoecious types.
A third group is parthenocarpic cucumbers. Parthenocarpic cucumbers do not require pollination to set fruit. They have no need for bee pollination and no need for a pollinizer which also increases yield potential. They will be nearly seedless or have unformed seeds. They should be isolated from seeded cucumber types to increase productivity and maintain the seedless nature. Parthenocarpic types should be considered when bee activity is limited such as in high tunnels, under row covers, or in very early plantings.
Concentrated fruit set in parthenocarpic pickling cucumbers.
Parthenocarpic cucumbers have been available for many years and include many types used in protected culture (greenhouse or high tunnel). Parthenocarpy has an advantage in that there is improved fruit set under what would be a poor pollination environment. Parthenocarpic pickle varieties also produce more fruits per vine for once-over harvest and therefore can be planted at half the stand of gynoecious types. The University of Delaware has been conducting trials on parthenocarpic pickles for over a decade and there is now a significant acreage of production in the region.
There are also differences in cucumbers in shape, skin, taste, and texture characteristics. There are thin skinned crunchy Beit Alpha middle eastern types, long Asian types, “burpless” types, non-bitter types, spined, rough, and smooth skin types, green and yellow types, egg shaped types, and long curly Armenian cucumbers which are actually related to melons but eaten like a cucumber.
One of the major concerns with cucumber selection is disease tolerance or resistance. Most varieties have good powdery mildew, scab, anthracnose, angular leaf spot, and cucumber mosaic resistance. Fewer have resistance to other viruses that are often present, particularly in late summer (watermelon mosaic, zucchini yellows mosaic, and papaya ringspot). The major disease that limits production from mid-summer on is downy mildew which comes up from the South on weather systems. There are only a handful of varieties currently with tolerance to this disease. In gynoecious slicing cucumbers, Bristol, SV3462CS and SV4719CS and associated pollenizers have intermediate resistance to cucumber downy mildew. In gynoecious pickles, Citadel, Peacemaker, and SVCN6404 with associated pollenizers have intermediate resistance. Further advances are being made in public and private breeding programs for improved downy mildew resistance.
Recommended cucumber varieties can be found in the Mid-Atlantic Commercial Vegetable Recommendations.
Parthenocarpic cucumbers are essentially seedless.