Search Results

You are looking at 1 - 10 of 11 items for

  • Author or Editor: Elden Stang x
  • Refine by Access: All x
Clear All Modify Search
Free access

Elden J. Stang and John Klueh

Spunbonded polypropylene fabric covers were applied over mature `Searles' cranberry (Vaccinium macrocarpon Ait. in the field during dormancy in 1989. Covers were selectively removed at 3 week intervals in April, May and early June after onset of growth. Plant canopy air temperatures under fabric were 5 to 6C higher than in exposed controls. Temperature differences up to 17C were measured in early June. Soil temperatures did not differ from the control until late May. Earlier greening of leaf tissue resulted in increased photosynthetic rates earlier in the growing season under fabric covers. Subsequent shoot dry weight was increased 5%; leaf size was not affected. A trend to increased fruit set (4 to 6%) with fabric cover treatments was observed when covers were applied for 6 or 9 weeks. Total fruit yield and anthocyanin content were not appreciably influenced by fabric covers.

Free access

Elden J. Stang and Gavin G. Weis

`Raritan' and `Guardian' strawberry were grown in the matted row system with controlled plant densities of 1, 2, 3, 4 or 5 plants/0.09m2 for comparison to a non-thinned matted row averaging 9 plants/0.09m2. Nitrogen treatments were superimposed on plant spacings at 3 week intervals in preharvest and postharvest applications. Total seasonal available N was 0, 36, 54 and 76 kg/ha. Fruit yield per plant decreased as plant population increased. Berry size declined with increased plant population but number of fruit per plant was not influenced. For both cultivars, plant populations of 4 to 5 plants/0.09m2 resulted in maximum fruit yield. Number of branch crowns for all treatments was 2.5-3.5/plant in the second growing season. Branch crown numbers were reduced with higher plant populations. N effects were independent of plant population effects and did not compensate for lower yields at low plant populations in more or larger berries. Optimum water management may be more important than N fertilizer in determing strawberry plant growth and yield.

Free access

Brian A. Birrenkott and Elden J. Stang

Selective flower removal was used in 1987 and 1988 to evaluate intraplant competition or inhibition within flowering uprights of `Searles' cranberry (Vaccinium macrocarpon Ait.). The lowest two flowers were removed from uprights at various stages of plant development in 1987. With one or both of the two earliest, i.e., lowest, flowers developing `into fruit, 25% of the remaining flowers matured into fruit. Removal of the earliest two flowers at preblossom or late blossom resulted in ≈ 46% fruit set for the remaining flowers. Slightly fewer upper flowers set (36%) when the earliest flowers and fruit were removed at early fruit development. In 1988, the lowest two flowers were removed at preblossom and natural insect pollination was supplemented by hand pollination. Hand-pollinated (upper) flowers set 58% when the lowest two flowers were removed, compared to 17% for the unthinned control. Yield and fruit numbers were lowered slightly as a result of flower thinning in both years. A significant amount of variation in fruit production was explained by the number of flowering uprights per unit of production area in both years.

Free access

Karim M. Farag, Jiwan P. Palta, and Elden J. Stang

The application of ethanol for enhancing effectiveness of ethephon under field conditions on cranberry (Vaccinium macrocarpon Ait.) fruit was tested during three seasons (1986 to 1988). The formulation containing ethephon plus the surfactant Tergitol (0.3% or 0.5%, v/v) and ethanol (2.5%, 5%, or 10%) consistently increased anthocyanin content in the fruit by 28% to 54% over the control. In general, fruit size was not affected by the ethephon treatment containing ethanol and Tergitol. The application of ethephon plus surfactant did not increase the anthocyanin content in the fruit. The presence of ethanol in the ethephon and surfactant mixture, however, consistently enhanced the fruit anthocyanin content by 21% to 40% as compared to ethephon plus surfactant. No adverse effect of various treatments on vine growth or appearance was noticed over the three seasons. Chemical name used: (2-chloroethyl) phosphonic acid (ethephon).

Free access

J. Angel Saavedra, Elden J. Stang, and Jiwan P. Palta

Uniconazole (UCZ) can control tree size by suppressing tree growth. Growth control of one year-old `Haralred' on MAC 9 `MARK' (dwarf) and EMLA 7 (semidwarf) rootstock was evaluated in the greenhouse. Uniconazole (65 or 130 mg/L) was sprayed 0, 1, 2 or 3 times at 3 week intervals. Total shoot growth was inhibited 31% and 24% on `MARK' and EMLA 7 rootstock, respectively, with 130 mg/L. Rootstock and scion diameter and number of leaves per tree were not affected by UCZ. Total leaf area on `MARK' rootstock increased when UCZ was applied once at 65 or 130 mg/L. On EMLA 7 two 130 mg/L sprays resulted in 22% less total leaf area compared to the control. UCZ applied three times reduced specific leaf weight on EMLA 7 trees 12% compared to the control. Branch angle was increased proportional to UCZ applications on semidwarf rootstock from 40° to 47°, and decreased on dwarf rootstock from 47° to 39°. Stomatal conductance increased 43% on `MARK' with 130 mg/L UCZ applied two times. Net photosynthesis of attached leaves did not differ. All UCZ treatments produced 18 to 56% fewer total flower clusters per tree than the control. UCZ appeared to delay bloom significantly.

Free access

Brian A. Birrenkott, Cynthia A. Henson, and Elden J. Stang

Cranberry (Vaccinium macrocarpon Ait. cv. Searles) vegetative tissue was analyzed at various stages of development to determine carbohydrate levels under field and greenhouse conditions and to identify the carbohydrates. Except during dormancy, cranberry uprights in the field had the highest concentration of carbohydrates (soluble and starch) at early blossom, when the lower flowers were at anthesis. As early flowers developed into fruit and upper flowers were at or just beyond anthesis, uprights had lower carbohydrate concentrations. As fruit growth slowed, soluble carbohydrate levels increased and were highest at dormancy. Upright shoot tissue produced the previous year and trailing woody stems followed the same trend as the current season's growth but had consistently lower soluble carbohydrate levels at each growth stage. Starch levels were low in current growth and did not change appreciably with fruit development. Starch was primarily stored and subsequently depleted in the previous season's upright growth and trailing woody stems. Tissue from the greenhouse was generally higher in carbohydrates than was field-grown tissue. Fruit developed from 53% of the flowers under greenhouse conditions, compared to 38% in the field. Insufficient carbohydrate levels may be responsible for the low fruit set observed in the field. Sucrose, glucose, fructose, raffinose, and stachyose were present in cranberry vegetative tissue.

Free access

Eric L. Zeldin, Brent H. McCown, Elden Stang, and John Klueh

A project to determine the comparative growth response of micropropagated (MP) and field propagated (FP) cranberry plants was conducted in field plots at a commercial cranberry marsh. Microcuttings were derived from shoot culture and rooted in either plugs or peat pots filled with peat. Replicated 1 m2 plots of MP plants and 15 cm FP cuttings were planted in June. Survival of MP plants after one month was significantly greater than that of the FP plants. Significant growth differences were observed later in the season. The MP plants produced more branches and greater runner elongation, resulting in a much greater ground cover. Many of the FP plants flowered and produced fruit, while the MP plants produced neither. Far fewer new flower buds were set in the fall on the MP plants. Potential advantages of MP cranberries include the fast, uniform establishment of new marshes and consequently earlier achievement of full productivity, and the rapid introduction of new genotypes from breeding or genetic engineering.

Free access

Rodney Serres, Elden Stang, Dennis McCabe, David Russell, Daniel Mahr, and Brent McCown

Genetic transformation of the American cranberry, Vaccinium macrocarpon Ait., was accomplished using electric discharge particle acceleration. Plasmid DNA containing the genes GUS (β-glucuronidase), NPTII (neomycin phosphotransferase II), and BT (Bacillus thuringiensis subsp. kurstaki crystal protein) was introduced into stem sections, derived from in vitro cultures, that had been induced to form adventitious buds. The stage of development of these adventitious buds was critical for efficient initial expression. After exposure to electric discharge particle acceleration, stem sections were cultured on a solid-phase bud-inducing medium containing 300 mg kanamycin/liter. In addition, a thin overlay of 300 mg kanamycin/liter in water was added to inhibit growth of nontransformed cells. Within 7 weeks, green shoots emerged amidst kanamycin-inhibited tissue. No escape (nontransformed) shoots were recovered, and 90% of the transformed shoots were shown through PCR and Southern blot analysis to contain all three introduced genes. GUS expression varied markedly among various transformed plants. Preliminary bioassays for efficacy of the BT gene against the feeding of an economically important lepidopteran cranberry pest have shown no consistently effective control. Potential problems with the expression of the BT and GUS genes are discussed

Free access

Elden J. Stang, Malcolm N. Dana, Gavin G. Weis, and Brent H. McCown