be used for large-scale production of hybrid seed. Hybrids were rapidly adopted by growers as a result of their significant increase in marketable yield as well as greater uniformity for horticultural traits compared with standard open
Peter T. Hyde, Elizabeth D. Earle, and Martha A. Mutschler
Richard W. Robinson
Bumblebees are commercially used to improve fruit set of greenhouse tomatoes, but they seldom pollinate tomatoes outdoors if not confined in a no-choice situation. Bumblebees frequently pollinated L. peruvianum and other self-incompatible (SI) Lycopersicon species, but not tomato plants, in the field at Geneva, N.Y. Bumblebees were very efficient pollinators of Sl Lycopersicon species, averaging only 5 s to pollinate one flower and fly to the next. Transfer of this attractiveness to pollinating insects to the tomato could improve fruit set of tomatoes grown in greenhouses with introduced bumblebees. It could also improve fruit set in the field, especially when conditions are poor for pollination. It has potential use for producing F1 hybrid seed, but associated problems make hybrid tomato seed production by insect pollination impractical now. Attractiveness to pollinating insects is being introgressed from L. peruvianum, L. hirsutum, and L. pennellii in the tomato breeding program at Geneva, N.Y. Several floral characteristics were found to be of importance for attracting pollinators, including the reaction to ultraviolet light. Flowers of SI species absorbed UV, whereas tomato flowers reflected UV light.
Richard T. Olsen, Thomas G. Ranney, and Dennis J. Werner
Inheritance of two mutant foliage types, variegated and purple, was investigated for diploid, triploid, and tetraploid tutsan (Hypericum androsaemum). The fertility of progeny was evaluated by pollen viability tests and reciprocal crosses with diploids, triploids, and tetraploids and germinative capacity of seeds from successful crosses. Segregation ratios were determined for diploid crosses in reciprocal di-hybrid F1, F2, BCP1, and BCP2 families and selfed F2s with the parental phenotypes. F2 tetraploids were derived from induced autotetraploid F1s. Triploid segregation ratios were determined for crosses between tetraploid F2s and diploid F1s. Diploid di-hybrid crosses fit the expected 9: 3: 3: 1 ratio for a single, simple recessive gene for both traits, with no evidence of linkage. A novel phenotype representing a combination of parental phenotypes was recovered. Data from backcrosses and selfing support the recessive model. Both traits behaved as expected at the triploid level; however, at the tetraploid level the number of variegated progeny increased, with segregation ratios falling between random chromosome and random chromatid assortment models. We propose the gene symbol var (variegated) and pl (purple leaf) for the variegated and purple genes, respectively. Triploid pollen stained moderately well (41%), but pollen germination was low (6%). Triploid plants were highly infertile, demonstrating extremely low male fertility and no measurable female fertility (no viable seed production). The present research demonstrates the feasibility of breeding simultaneously for ornamental traits and non-invasiveness.
Xiuli Shen, William S. Castle, and Frederick G. Gmitter Jr
naturalized. Because of their spread and the prolific seed production of C. equisetifolia (the only monoecious species of the three species), they were grouped, classified as invasive, and became regulated by the Florida Departments of Environmental
D. Spaner, D.E. Mather, and R.A.I. Brathwaite
Immature field corn (Zea mays L.) grown for pre-lenten carnival festivities in Trinidad and Tobago can be a profitable cash crop. Hybrid and local unimproved open-pollinated corn were grown with two levels of weed control and fertilizer application late in the rainy season at two locations each on Trinidad and on Tobago. The Trinidad locations were situated on more productive agricultural land than those on Tobago. The hybrid `Pioneer 3098' yielded more edible corn than the local variety at all locations and at all treatment levels. Manual weed removal at the four- to five-leaf stage was sufficient to allow corn to out-compete the weed canopy, and an additional field operation would not be justifiable. On Tobago, the application of fertilizer just before tasselling, in addition to an earlier application of urea, increased the number and yield of edible ears. Few boiling-quality, marketable ears were produced on Tobago. On Trinidad, the additional fertilizer did not alter yield. For commercial carnival-season production of immature field corn on productive soils in Trinidad, the purchase of imported hybrid seed is economically justifiable, but high inputs into weed control and fertility management may not be needed.
Gabriele Gusmini, Jonathan R. Schultheis, and Todd C. Wehner
Salted and sweet watermelon rind pickles are commonly produced in North America, Europe, and Asia using traditional recipes. Homeowners and small industries use the leftover watermelon crop, especially from cultivars having thick and crisp rind, to produce pickles. Recently, we classified rind thickness for a set of obsolete and heirloom cultivars used by home gardeners and heirloom collectors in the United States. In this study, we used elite cultivars for growers interested in high yield, fruit quality, adaptability, and disease resistance. The objective of this study was to classify modern cultivars (nine inbreds and 103 F1 hybrids) of watermelons available to growers for use in production of watermelon rind pickles. Based on the data, cultivars were divided into three groups of rind thickness and categorized according to pedigree (inbred or F1 hybrid), fruit type (seeded or seedless), and flesh color (red, orange, or yellow). Most of the cultivars tested (109 of 112) had rind thicker than 10 mm and could be used for pickle production.
Sandra M. Reed, Keri D. Jones, and Timothy A. Rinehart
collected for embryo rescue and 199 were allowed to mature on the plants. Table 1. Comparison of embryo rescue and seed germination for production and survival of hybrids between Dichroa febrifuga GUIZ 48 and three cultivars of Hydrangea
L. Brandenberger, M. Baker, D. Bender, F. Dainello, R. Earhart, J. Parsons, R. Roberts, N. Roe, L. Stein, M. Valdez, K. White, and R. Wiedenfeld
93 POSTER SESSION 12 (Abstr. 207-237) Crop Production Friday, 30 July, 1:00-2:00 p.m.
Dario J. Chavez and Paul M. Lyrene
screening for functional 2n gamete production, they provided repeatable results. Table 1. Number of flowers pollinated, and fruit, seed, and hybrid seedling production in interspecific crosses between Vaccinium darrowii and southern highbush
Hybrid seed of cucumber (Cucumis sativus) is expensive to produce. Production of `artificial seeds' through somatic embryogenesis may be a viable alternative. Somatic embryos were induced, multiplied on a semisolid medium for 8-10 weeks, and germinated on agar-gelled medium before transplanting to soil. It was then important to determine the extent of variation among plants derived from somatic embryos. The criteria for variation among regenerants of cultivar Clinton were; plant height, fruit shape, fruit weight and number (yield/plant), days to first female flower and variation in selected isozymes. All measurements were taken on greenhouse-grown plants. Some regenerants of Clinton were also planted in the field and they flowered and, qualitatively, bore fruit as well as the zygote-derived plants. When quantitative measurements were made, variation was greater than for plants from zygotic embryos, but the visual impact was that there was little variation amongst regenerants. Regenerants grew more slowly and tended to yield higher numbers of slightly smaller fruits than plants from zygotic embryos. Average yield per plant was higher for somatic embryo-derived plants. For cultivar Corona only morphology of plant and fruit was examined. One plant was especially visually mutant and unacceptable as a commercial plant. The defects were readily identifiable in the seedling stage. Preliminary evidence suggests that `artificial seeds' of cucumbers may be a viable proposition.