Commercial Production of Pickling &
Slicing Cucumbers in North Carolina

Terminology and Application

Advances in cucumber breeding have prompted introduction of several terms to describe cucumber cultivars. Cucumbers can exhibit different flowering and vining characteristics.

Flowering

Predominantly gynoecious cultivars produce almost all female flowers on the same plant, so they must be interplanted with monoecious pollenizer plants that produce mostly male flowers. Such cultivar blends usually have 10 to 15% pollenizer to ensure an adequate supply of pollen. In cucumbers, all predominantly gynoecious cultivars are hybrids but not all hybrids are predominantly gynoecious.

Monoecious cultivars produce separate male and female flowers on the same plant. An example of a hybrid monoecious inbred is Poinsett 76.

Hybrids are the offspring derived by crossing two unique inbred lines. Seed from fruits produced from hybrid seed cannot be saved because two specific inbred lines must be used exclusively to obtain hybrid seed. Seed companies do not publicize inbred (parents') identities of superior cultivar hybrids so that hybrids can be sold exclusively for profit.

Inbred (sometimes referred to as open-pollinated) cultivars are true-breeding cultivars which are self pollinated with male and female flowers on the same plant (called monoecious). Seed can be saved from an open-pollinated cultivar. That seed will produce the same cultivar when grown the following season. Because hybrids bring greater revenue from seed sales, most commercially sold cultivars are hybrids and not inbreds.

Parthenocarpic cucumber cultivars do not require pollination (pollen transfer from the male to the female flower) to set fruit. Nonfertilized fruits are seedless. Commonly grown parthenocarpic cultivars are the "burpless" or "European" cucumber types (10 to 14 inches long) typically produced in the greenhouse. Some field-grown cultivars are parthenocarpic. However, these cultivars usually are not seedless because flowers are often pollinated by wild bees. An example of a field-grown parthenocarpic cultivar is H-19, a little-leaf type.

Pistillate flowers are female flowers that produce fruit. The flower has an ovary below the petal ( Plate 3).

Monoecious cultivars are used as pollen sources or pollenizers for the predominantly gynoecious cultivars to ensure that adequate pollination occurs, resulting in good fruit set and well-formed fruit. Many seed companies have developed their own monoecious pollenizers to blend with certain cultivars although Sumter and Poinsett 76 cultivars are often used. A good pollenizer should have plenty of male flowers to provide sufficient pollen for adequate pollination, have male flowers that open before the female flowers on the predominantly gynoecious cultivar open, and yield well and produce fruit similar in quality to the predominantly gynoecious cultivar. The seed label should indicate how much and what pollenizer seed is blended with the seed of the predominantly gynoecious cultivar. Approximately 10 to 15% pollenizer seed should be blended with seed of the predominantly gynoecious cultivar to maximize yields (Miller 1976).

Staminate flowers or male flowers have no ovary attached (Plate 3) but are necessary because they provide pollen for pollination. Male flowers must open (anthesis) when female flowers open for pollination, fruit set, and production of quality fruit.

Vining

In determinate plants, vine growth of the main stem ceases after a period of time (Denna 1971) with formation of floral tissue at the vine terminal (Staub and Crubaugh 1995). Determinate plant types have less vine growth, more concentrated fruit set, and fruit produced nearer to the base of the plant than indeterminate types. Determinate-type plants must be managed more intensively than the indeterminate (vining) type because they are more sensitive to environmental stress (from increased fruit load on smaller plants). With determinate plant types, fruit are easier to pick and high yields have often been obtained, particularly when grown on black plastic mulch.

Indeterminate, or vining types, continue to grow indefinitely as flowers are produced continuously throughout plant growth. Vining types typically produce fruit farther from the base of the plant than determinate types. Indeterminate plants are larger and more tolerant of stress conditions because they usually have more leaves to support fruit growth and development.

Little-leaf is a mutant line that was reported in Arkansas in 1980. It produces a plant with leaves that have one-fourth to one-half less leaf area than standard cucumber cultivars (Goode et al. 1980) (Plate 32). The little-leaf plant type has a multibranching habit which coincides with fruiting, which might result in increased yield. One little-leaf cultivar (H-19) was made available to the processing industry but was not widely accepted commercially because of seed maturation (hard seed) in grade 3-size fruit. Reduced maturation of seed in grade 3 fruit in little-leaf types is currently being addressed by breeders.