An extensive study (276 samples) was conducted in 1960 to correlate cranberry (Vaccinium macrocarpon, Ait.) bog soil pH and productivity (Chandler, F. B. and Demoranville, I. E. 1961. Cranberries 26(3):9-10). At that time, soil pH averaged 4.37 and excellent productivity was represented by a yield greater than 10 mT/ha. Thirty years later, when more than 28 mT/ha is considered good yield, soil samples will be collected from these same sites and evaluated for pH by the methods used previously. Production records for the pact three years will be obtained and the average value for each location used to construct a regression of bog yield vs soil pH. Information presented will include: 1. productivity vs soil pH in 1960 and 1990; 2. change in soil pH after 30 years?; 3. possible reasons for changes-if any (grower interviews); 4. implications for the future.
Paul J. Croft, Mark D. Shulman, and Roni Avissar
Cranberry (Vaccinium macrocarpon Ericaceae Ait.) stomatal conductivity (SC) was investigated in the field to examine plant response as a function of weather conditions. Measurements were made during fruit maturation on 14 days between 0540 and 1710 h r, as weather conditions permitted. SC ranged from 0.02 to 0.08 cm·s-1 and was much lower than for most other crops. Scatter plots of SC vs. leaf temperature by day indicated only a weak linear relationship. When the data were stratified by time of day and by clear and overcast skies, several significant Pearson correlation coefficients suggested a stomatal response. The findings, when combined with current knowledge of the physical structure of cranberry stomata, suggest that cranberries behave as xeromorphic plants.
Teryl R. Roper and Marianna Hagidimitriou
Carbohydrate concentration may be important for flower initiation and fruit set in cranberry (Vaccinium macrocarpon Ait.). Fruit set has been shown to be a major limiting factor in yield component analysis. The objective of this research was to identify carbohydrate concentrations in cranberry tissues at various stages of development under field conditions. Samples of two cranberry cultivars, `Stevens' and `Searles' were collected during the 1989 season using a 13 cm diameter probe. Samples were divided into fruit, uprights, woody stems and roots. Carbohydrates were quantified by HPLC. Nonstructural carbohydrates were primarily sucrose, glucose, fructose and starch. Soluble carbohydrate concentration was stable throughout the season in tissues analyzed, while starch content was high early in the season then decreased during blossom and fruit set. This work shows that starch reserves in leaves and stems apparently are remobilized to support fruit set in cranberry.
Bernadine C. Strik, Teryl R. Roper, Carolyn J. DeMoranville, Joan R. Davenport, and Arthur P. Poole
This research was undertaken to document the extent of biennial bearing in flowering uprights by American cranberry (Vaccinium macrocarpon Ait) cultivar and growing region. Seven cultivars were studied: three found in all states considered (Massachusetts, New Jersey, Wisconsin, Oregon), two common to Massachusetts and New Jersey, and two other commercially grown cultivars, one each from Wisconsin and Oregon. There were significant cultivar, region, and cultivar × region interaction effects for both percent return bloom (%RB) and percent return fruit (%RF). Percent RB ranged from 74% for `Ben Lear' in Wisconsin to 14% for `Howes' in New Jersey. `Ben Lear' differed the most in %RB among regions, from 74% in Wisconsin to 14% in Massachusetts. However, in some regions, especially in Wisconsin, many blossoms did not set viable fruit. There was no significant difference in %RB among cultivars grown in Massachusetts or Oregon; however, cultivars grown in these regions did differ in %RF.
Rod Serres, Brent McCown, Dennis McCabe, Elden Stang, Dave Russell, and Brian Martinell
Electric discharge particle acceleration was used to introduce three foreign genes into the American cranberry (Vaccinium macrocarpon Ait.). These genes were NPTII (conferring resistance to the antibiotic, kanamycin), GUS (allowing for visual verification), and B.t. (conferring resistance to lepidopteran insects). Adventitious buds were induced on stem sections prior to bombardment with DNA-coated gold pellets. Bombarded stem sections were then transferred to a selection medium containing kanamycin. The surface of the medium was overlaid with a thin layer of kanamycin solution. Approximately 35 days after blasting, proliferating cell masses and elongating shoots were observed amidst the mass of kanamycin-inhibited tissue. Seven weeks after blasting, a histochemical assay verified GUS expression in these tissues, and polymerase chain reaction was used to confirm the presence of the introduced genes.
Rod Serres, David Russell, Dan Mahr, and Brent McCown
Genetically transformed Vaccinium macrocarpon `Stevens' and `Pilgrim' plants have been obtained using electric discharge particle acceleration. Three foreign genes, kan encoding a selectable marker, gus a reporter gene, and B.t.k. conferring lepidopteran resistance, were incorporated into the genome. Expression of kan was assayed by culturing shoots in vitro on media with several concentrations of kanamycin. Expression among transformed clones (transclones) varied from high resistance (normal growth at 300 mg/L kan) to no resistance. Histochemical analyses for gus expression revealed variability among transclones. Some transclones exhibited no gus expression, others had consistent area-specific expression while others displayed random expression. In preliminary feeding trials with blackheaded fireworm larvae, B.t.k. expression was found to be ineffective at controlling insect development. We have recovered plants transformed with a different promoter driving the B.t.k. gene in an effort to enhance expression.
Hilary A. Sandler
The benefit of applying an antitranspirant for protection of cranberry (Vaccinium macrocarpon Ait.) vines exposed to desiccating conditions was evaluated at four different sites, two sites per year, for a period of 1 year each. Overall, plots receiving one fall application of an antitranspirant produced more berries and greater total fruit mass the following year than did nontreated plots. Overall dry leaf mass was not significantly affected. At one site, treated plots had more flowering uprights and more flowers per upright per unit of ground area than the nontreated plots. For cranberry growers who cannot maintain a winter flood, one fall application of pinolene (Vapor Gard) may offer some protection against winter injury. Further research is needed to document long-term yield effects as well as to clarify the role of the antitranspirant in protecting exposed vines and floral buds against adverse winter conditions. Chemical name used: di-1-p-menthene (pinolene).
Charles F. Forney
High-quality cranberry (Vaccinium macrocarpon) fruit are required to fulfil the growing markets for fresh fruit. Storage losses of fresh cranberries are primarily the result of decay and physiological breakdown. Maximizing quality and storage life of fresh cranberries starts in the field with good cultural practices. Proper fertility, pest management, pruning, and sanitation all contribute to the quality and longevity of the fruit. Mechanical damage in the form of bruising must be minimized during harvesting and postharvest handling, including storage, grading, and packaging. In addition, water-harvested fruit should be removed promptly from the bog water. Following harvest, fruit should be cooled quickly to an optimum storage temperature of between 2 and 5 °C (35.6 and 41.0 °F). The development of improved handling, refined storage conditions, and new postharvest treatments hold promise to extend the storage life of fresh cranberries.
Hilary A. Sandler, Carolyn J. DeMoranville, and Wesley R. Autio
A 2-year field trial examined the interaction of nitrogen rate, vine density, and weed management options for establishing new cranberry (Vaccinium macrocarpon) plantings. Utilizing the vigorous hybrid, `Stevens', the cost-efficiency of the treatment combinations was evaluated by combining cranberry and weed biomass data with various economic estimates. The most cost-effective production scheme for establishing new cranberry beds is to plant vines at a low density, use moderate rates of nitrogen, and apply an annual application of a preemergence herbicide. This combination produced substantial vine coverage at very low cost, reduced weed biomass by 85% compared to untreated plots, and gave the best weed control per dollar spent. Growers may opt for other reasonably successful combinations that involve higher labor costs if they can produce their own cuttings (reducing initial costs) or if they are farming with the intent to reduce overall synthetic inputs.
Shiow Y. Wana, John L. Maas, and Gene J. Galletta
Ellagic acid, a putative anticarcinogenic compound, was detected in plants of mayhaw (Crataegus spp.), false strawberry (Duchesnea indica), strawberry (Fragaria spp.), black currant (Ribes nigrum), thornless blackberry (Rubus subgenus Eubatus), red raspberry (Rubus subgenus Idaeobatus), and cranberry (Vaccinium macrocarpon). Large differences in ellagic acid contents have been found among species and cultivars and also among tissues. Ellagic acid content in plant tissues is also affected by environmental factors and shows a seasonal variation in strawberry leaves. A decrease in ellagic acid content of leaves was associated with seasonal decreases in photoperiod and temperature from September to December. Ellagic acid content in the leaves of red raspberry infected with orange rust showed more than a 3-fold increase compared to healthy leaves.