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James Polashock and Nicholi Vorsa

We have used RAPDs (Randomly Amplified Polymorphic DNAs) to successfully fingerprint cranberry. Although this method is simple and inexpensive, disadvantages include limited reproducibility in other labs and it is not easily computer-analyzed. RAPDs can also be labor-intensive because multiple primers are required to adequately fingerprint a single sample. As an alternative, we have utilized a method called SCARs (Sequence Characterized Amplified Regions). Clear polymorphic RAPD markers were cloned and sequenced. Primers were designed to amplify each polymorphic band and contained the original 10-mer RAPD primer sequence and 10 to 12 additional “clone-specific” bases. Primer sets were tested on eight common cranberry cultivars to determine if the desired polymorphic marker was amplified. The success rate of developing ëgoodí primer sets was ≈25%. The most common problem was loss of polymorphism, suggesting that selectivity was contained within the original 10-mer RAPD primer. The amplification of many similarly sized markers, suggesting the primer set amplified a repeat region, was another problem. Useful primer sets were multiplexed in PCR reactions to establish a “fingerprint.” The SCARs system we developed to fingerprint cranberry is powerful enough to distinguish individual clones in both crosses and selfed progeny. To further simply the system, computer automation for detection and analysis using fluorescently labeled primers is underway. One problem we are addressing is reduced product in the labeled multiplex reactions. Reduced product yield is presumably because the dye molecule (Cy5) is very large and may reduce primer binding and/or polymerization efficiency. This problem has been somewhat alleviated using a patented form of Taq DNA polymerase.

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Beth Ann A. Workmaster, Jiwan P. Palta, and Jonathan D. Smith

In Wisconsin, the cranberry plant (Vaccinium macrocarpon Ait.) is protected from freezing temperatures by flooding and sprinkle irrigation. Due to the high value of the crop, growers typically overprotect by taking action at relatively warm temperatures. Our goal is to provide recommendations for improved frost protection strategies by studying seasonal hardiness changes in different parts of the cranberry plant (leaves, stems, buds, flowers, fruit). Stages of bud growth were defined and utilized in the hardiness determinations. Samples were collected from mid-April to mid-Oct. 1996 and cuttings were subjected to a series of freezing temperatures in a circulating glycol bath. Damage to plant parts was assessed by visual scoring and observation, ion leakage, and evaluation of the capability to regrow. The following results were obtained: 1) Overwintering structures, such as leaves, stems, and buds, can survive temperatures <–18°C in early spring, and then deacclimate to hardinesses between 0 and –2°C by late spring. 2) In the terminal bud floral meristems are much more sensitive to freeze–thaw stress than are the vegetative meristems. 3) Deacclimation of various plant parts occurred within 1 week, when minimum canopy temperatures were above 0°C, and when the most numerous bud stage collected stayed the same (bud swell). 4) Fruits >75% blush can survive temperatures of –5°C for short durations. By collecting environmental data from the same location we are attempting to relate plant development, frost hardiness, and canopy temperatures (heat units).

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Teryl R. Roper and John S. Klueh

The source of photosynthate for developing cranberry (Vaccinium macrocarpon Ait.) fruit can be partitioned spatially among new growth acropetal to fruit, 1-year-old leaves basipetal to fruit, and adjacent uprights along the same runner. Cranberry uprights were labeled with 14CO2 in an open system with constant activity during flowering or fruit development. When new growth acropetal to fruit was labeled, substantial activity was found in flowers or fruit. Little activity was found in basipetal tissues. When 1-year-old basipetal leaves were labeled, most of the activity remained in the labeled leaves, with some activity in flowers or fruit. Almost no labeled C moved into acropetal tissues. When new growth of adjacent nonfruiting uprights on the same runner were labeled, almost no activity moved into the fruiting upright. These data confirm that new growth acropetal to developing flowers and fruit is the primary source of photosynthate for fruit development. Furthermore, they show that during the short time studied in our experiment, almost no C moved from one upright to another.

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Bruce D. Lampinen

Although capillary rise plays an important role in providing water to cranberry plants, the relation between water level and plant establishment and growth has not been adequately studied. The aim of this study was to maintain constant water levels and to monitor the effects on establishment, root growth, and aboveground growth in greenhouse-grown cranberries. Cuttings from cranberry (Vaccinium macrocarpon Ait.) cultivar Stevens were rooted in sand-filled pots in the greenhouse for ≈2 weeks and then transplanted to sand-filled PVC tubes. The water level in the tubes was set 7.5, 15, 22.5, 30, or 37.5 cm below the top of the sand surface. Pan evaporation was estimated using PVC tubes filled with water to the same level as the sand in the planted tubes. Extension growth of uprights and runners was measured every 3 days. After growing in the PVC tubes for 90 days, all plants were harvested and upright length, runner length, leaf dry weight, stem dry weight, root length, and root dry weight were measured. There was a similar mortality rate among plants in all of the treatments. Water use varied among the treatments, with the 7.5-cm water level treatment using the least water. The 15-cm water level used the most water, with water use then decreasing in a linear fashion for the 22.5-, 30-, and 37.5-cm treatments. At the conclusion of the study, aboveground dry weight was significantly less for plants in the 7.5-cm treatment compared to any of the other treatments, while it was highest in the 15-cm water level treatment and decreased with lower water levels in a linear fashion as did the average daily water use. The patterns of root dry-weight accumulation were different among the treatments with the highest accumulation in the 22.5-cm water level treatment and decreasing root dry weight with both higher and lower water level treatments. This study points out the detrimental effects of a too high water table, but it also shows that there are costs associated with establishing a deeper rooting system. The benefit of the deeper root system probably outweighs the cost of production however, since shallow root systems lead to increased susceptibility to drought stress and decreased access to nutrients.

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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.

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Kim D. Patten and John Wang

The relationships between canopy density of three perennial weed species (Potentilla pacifica Howell, Aster subspicatus Nees, and Lotus corniculatus L.) and `Mcfarlin' and `Stevens' cranberry (Vaccinium macrocarpon Ait.) yield and fruit quality were evaluated. Yield was more severely affected by weed interferences than fruit size or color. Best-fit regression equations for the effects of weed density on yield, fruit size, and color were linear or quadratic polynomials with a strong linear component. For each bog, the slope of the linear relationship between yield and weed density was more negative as the mean yield of weed-free controls increased. `Stevens' fruit size and yield were more sensitive and fruit color was less sensitive to changes in P. pacifica population density than those of `McFarlin'.

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Carolyn J. DeMoranville

Levels of major elements (N, P, K, Mg, Ca) in `Early Black' cranberry (Vaccinium macrocarpon Ait.) tissues changed during the season (April to October). A distinct pattern was associated with each tissue type (old leaves, woody stems, new shoots, roots, fruit) and each element. However, the pattern for a given element in a given tissue was similar from year to year. For example, nitrogen levels in old leaves rose early in the season and then declined in old leaves as new shoot tissue was produced. The early-season rise in nitrogen levels in old leaves coincided with a decline in nitrogen in woody stem tissue. Changes in the amount of applied nitrogen led to changes in nitrogen levels in new shoots after a 2 year Iag. While N, K, Ca, and Mg content (% dry weight) in roots is lower than that in other tissues, there is great biomass of root tissue, so that root tissue represents a large pool of these elements. Roots, along with woody stems and old leaves may represent a reservoir of major elements for new shoot development early in the season, prior to fertilizer application. Levels of the major elements in new shoot tissue achieved a steady state in August, an indication that this is a good time to collect tissue for routine testing.

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Justine E. Vanden Heuvel and Carolyn J. DeMoranville

Competition between fruit and upright growth in cranberry has not been previously studied, but negative correlations reported between upright length/dry weight and yield indicate that sink demand from vegetative tissues may reduce fruit production. `Stevens', `Howes', and `Early Black' uprights and fruit were collected on either a weekly or bi-weekly basis through the growing seasons of 2002–04. The data indicated a shifting of resource allocation from leaf area and dry weight accumulation to fruit growth when about 1500 growing degree days (GDD, base 4.5 °C) had accumulated. Following the initial surge in fruit growth, leaf area and dry weight accumulation resumed at roughly 2300 GDD, resulting in a competition for resources with the developing fruit until after 3000 GDD. A lag phase in fruit diameter and dry weight accumulation was noted in some cultivars in some years, and may be partially due to the resumption of leaf growth. Roots, uprights, and fruit may all compete for resources during the hottest portion of the growing season.

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Carolyn J. DeMoranville

In Massachusetts, cranberry (Vaccinium macrocarpon) bogs were historically developed in existing wetlands and new plantings are now established in mineral soils that are converted into constructed wetlands. To streamline the interaction between cranberry farming and wetlands protection, the state has defined “normal agricultural practices” that are exempt from wetlands regulations under certain circumstances. As part of that process and to qualify for the exemption, farmers are required to have a conservation farm plan and demonstrate the use of best management practices (BMPs) on their farms. The University of Massachusetts Amherst Cranberry Experiment Station (UMass Cranberry Station) was engaged to bring together the U.S. Department of Agriculture, Natural Resource Conservation Service (NRCS) and cranberry industry representatives to define BMPs specific to cranberry farming practices. Initially, the documents were reviewed by scientists and regulators for soundness of science and rigor of environmental protection. A grower committee reviewed the proposed BMPs to determine if the BMPs could be implemented on real farms. The next stage of the project consisted of defining areas where more research was needed to formulate good BMPs. In particular, research projects were initiated to study nitrogen and phosphorus nutrition. This research has become the basis for nutrition BMPs, national cranberry nutrition guidelines, and standards used by NRCS for cranberry nutrient management plans. The cranberry BMP project has continued with a regular cycle of revision and additions based on grower-identified needs for horticultural and environmental guidance. This connection to the growers, along with the regulatory link, accounts for the widespread adoption of BMPs in the cranberry industry. Local NRCS estimates that 75% to 80% of Massachusetts cranberry growers have current conservation farm plans that include BMP implementation.

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Kim Patten, Rod Macfarlane, and Dan Mayer

The pollination of cranberries and pears by honey bees is often inadequate. The pollination efficacy of feral (Bombus spp.) and/or commercial bumble bees was evaluated for these crops. Preliminary evaluation of commercial B. vosnesenskii and B. occidentalis hives indicated poor forage activity on pears, but good activity on cranberries. Hive stocking densities of B. occidentalis on cranberries required to match feral Bombus populations was 8-10 hive/ha. Hives required 1-2 weeks in the field prior to full bloom to achieve suitable forage density during bloom. Parasitism of commercial hives by wax moth and bumble bee brood fly was common. Commercial colonies did not appear to be cost effective at this time. Only short-tongued feral Bombus species foraged on cranberries. Acceptance of artificial domiciles by these species was poor. Enhancing feral populations required provision of supplemental food sources and improved nesting habitat. Management of alternative food resources for feral bumble bees will be discussed.