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One cannot review the history of vegetable breeding without being impressed by the extent to which some of our crops are dependent on a relatively few characteristics originally derived from introduced material. Several important vegetable crops would not exist as they do today without the introduction of disease resistance and horticultural characteristics from distant parts of the world.

Four sets of nearly isogenic bacterial wilt [Erwinia tracheiphila (E.F. Smith)] Holland resistant and susceptible gynoecious cucumber (Cucumis sativus L.) lines, along with their companion segregating generations were evaluated under replicated field conditions for flowering date, fruit quality, fruit number, and length : diameter ratio (L:D). In addition to flowering earlier, susceptible lines were higher-yielding and had longer fruits than their resistant counterparts. Although differences in fruit quality were not significant, susceptible lines were preferred by a panel of seven judges. Compared to susceptible lines, hybrid progeny were later-flowering and in some instances lower-yielding.

Silver nitrate and gibberellin A4/A7 (GA4/7) were compared for induction of staminate flower production on an inbred gynoecious cucumber (Cucumis sativus L.) line grown in the field at Madison, Wisconsin. Foliar sprays of silver nitrate at 100, 200, and 400 ppm induced significantly more staminate flowers per plant than did GA4/7 at the standard, widely-used rate of 50 ppm, making gynoecious x gynoecious hybrid seed production commercially feasible. The strong induction all plants treated with silver nitrate should minimize the genetic shift toward maleness observed from one generation to the next when GA is used to increase seed of gynoecious parental lines.

Wisconsin 2843 (WI 2843), a cucumber (Cucumis sativus L.) germplasm release from the USDA and the Univ. of Wisconsin was announced to United States cucumber breeders in March of 1983. It was developed to provide a source population having multiple disease resistance, variable fruit characteristics, and processing qualities from which superior inbred parents might be extracted.

A strong linkage (~ 1 crossover unit) was detected between the gene Bw for resistance to bacterial wilt incited by Erwinia tracheiphila (E. F. Smith) Holland and the gene M for pistillate vs. perfect flowers in cucumber (Cucumis sativus L.).

A greenhouse cucumber (Cucumis sativus L.) population, Wisconsin 5207G (WI 5207G), was released in Dec. 1984 by the ARS/USDA and the Univ. of Wisconsin Agricultural Experiment Station. It was made available to U.S. cucumber breeders to supply a source from which they may extract multiple disease resistant (MDR) lines with fruit and vine characteristics suitable for field and greenhouse production.

Silver nitrate at 100, 200 and 400 ppm and aminoethoxyvinylglycine (AVG) at 50, 100 and 200 ppm induced perfect flowers on gynoecious muskmelon (Cucumis melo L. cv. MSU-1G) in the greenhouse. Some phytotoxicity was observed in plants treated with AgNO3 and AVG at the higher concentrations.

Hybrid carrots (Daucus carota L.) are gaining a larger share of the market once devoted exclusively to open-pollinated cultivars. The carrot inbred Florida 524 has been used extensively as the male parent in experimental hybrids tested in Florida, California, Wisconsin, Texas, and Arizona. These trials have revealed that Florida 524 has good combining ability for fresh market characteristics. Florida 524 is being released jointly by the University of Florida and the U.S. Department of Agriculture.

Carotenes from vegetables and fruits are vitamin A precursors that contribute about half of the vitamin A in the U.S. diet (3) and two-thirds of the world diet (5). Carrots typically contain 65 to 90 ppm carotenes (1) and are estimated to be the major source of carotene for U.S. consumers (3). Few pro-vitamin A sources surpass the carotene content of typical carrots, although red palm oil can contain >825 ppm carotenes (2). Genetic selection for higher carotene levels in carrots could increase the dietary consumption of carotene and consequently vitamin A. A high carotene mass carrot population was developed for use in breeding, genetic, and biochemical studies of carrot (Fig. 1).

Aminoethoxyvinylglycine (AVG) at 50,100, and 200 ppm induced staminate flowers on 3 gynoecious cucumber lines in the greenhouse. Both the time of application and the type of water used to prepare the AVG solutions had a significant effect on the node at which conversion from pistillate to staminate first occurred and on the total number of nodes bearing staminate flowers. Plants treated with 100 and 200 ppm AVG were chlorotic for about 10 days after application.

Wisconsin 1983 cucumber (Cucumis sativus L.) was released in Feb. 1984 by the USDA and the Univ. of Wisconsin-Madison to provide breeders with a line having high fruit quality and multiple-disease resistance to produce hybrid cultivars and germplasm for breeding purposes. (Resistance identified in green house evaluation for anthracnose and downy mildew was confirmed in field tests conducted by E.V. Wann, U.S. Vegetable Laboratory, ARS/USDA, Charleston, S.C.)

In cucumber (Cucumis sativus L.) a recessive gene designated sc (stunted cotyledon) produces small, dark green, concavely curved cotyledons with chlorotic tips with pleiotropic effects of plant weakness and stunting, cupped leaves, and abnormally shaped flowers.

Black spine color of fruit in cucumber is controlled by either of two dominant genes B and C. The double recessive (bbcc) is white. No linkage was observed between fruit spine color and cotyledon bitterness.

Flavor is an important factor in establishing consumer preference of carrots. Although harsh, strong flavor frequently occurs in available cultivars, the dominance of mild flavor in hybrids from harsh and mild parents suggests that carrot flavor can be improved rapidly when mild-flavored inbreds are available (1). Carrot inbred B2566 has been selected as a source of improved flavor and was used as a male parent in experimental hybrids tested in California, Florida, and Wisconsin. B2566 has demonstrated good combining ability for important fresh market characteristics of color, shape, and seed productivity along with desirable mild, sweet flavor and succulent texture. Because of these qualities, B2566 is being released jointly by the USDA, the Univ. of Florida, and the Univ. of California.

The muskmelon (Cucumis melo L.) breeding population Wisconsin (Wl) 998 was developed jointly by the U.S. Department of Agriculture, the University of Wisconsin, and Michigan State University to provide breeders and seedsmen with a source from which gynoecious inbreds can be developed for use in the production of hybrid cultivars. In addition to a high incidence of gynoecious plants, WI 998 provides other useful plant and fruit characteristics.

‘Wautoma’ (Fig. 1), a multiple-disease resistance, monoecious-processing cucumber (Cucumis sativus L.) inbred, was released 19 Feb. 1984 by the USDA. Currently available monoecious varieties are not suitable for blending with some of the new hybrids that have multiple-disease resistance and bitter-free fruits. ‘Wautoma’ is recommended for use as a pollinator to blend with seed of multiple-disease resistant hybrids, and as a pollen parent in hybrid development. In 1983 and 1984, it was tested in observational and processing trials under breeding line number WI 1902M.

The open pollinated carrot (Daucus carota L.) ‘Beta III’ was released and widely distributed in 1986, primarily for its value as a garden cultivar and for an improved source of carotenes for providing vitamin A. It is a promising population for breeders to extract inbred lines for improved hybrids.