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.
Charles F. Forney
Paul J. Croft
The Northeast Regional Climate Center, Ocean Spray Cranberries, and the American Cranberry Growers Association provided support for this study. Thanks to Dave Fittante, Rich Hartman, Paul Eck, and Mark Shulman, and the anonymous reviewers for
T.R. Roper, D.L. Mahr, and P. Kaarakka
Cranberry Crop Manager is a predictive software package for commercial cranberry growers. The package consists of linked modules. Predictive models for insect, disease, and weed development are the most important features. With appropriate weather and scouting information the models will make control or no control recommendations. To support the predictive models the program will maintain weather records of air temperatures, evapotranspiration, irrigation, and rainfall. Data can be imported or entered by hand. The program will maintain bed records including pesticide applicators, pesticide and fertilizer applications, and scouting reports. Output options include screen or printed reports or data export. An electronic encyclopedia of cranberry disease, insect and weed pests on CD will accompany the package. Minimum computer requirements are 486 CPU, 6 MB RAM, 6 MB hard drive space.
Luping Qu, James Polashock, and Nicholi Vorsa
Putative transgenic cranberry plants have been achieved via Agrobacterium-mediated transformation. Leaf explants were transformed with a supervirulent Agrobacterium tumefaciens strain EHA 105, harboring the binary vector P35SGUSint and nptII selectable marker genes. Inoculation of precultured explants (≈10 days on regeneration medium) coupled with sonicasion improved transformation efficiency significantly. Adventitious shoots were directly regenerated from explants. Putative transformed shoots were identified by being kanamycin-resistant and GUS-positive. Stable GUS gene expression (turning blue) could be detected within 1 h of incubation at 37 °C. Confirmation of transformation by molecular analysis is in progress. Eight putative transgenic cranberry plants were obtained. All appeared morphologically normal. This appears to be the first success in achieving cranberry transformed plants by Agrobacterium-mediated method. Optimizing the transformation system is ongoing.
Beth Ann A. Workmaster and Jiwan P. Palta
study was supported by a grant from Wisconsin Cranberry Board and by the College of Agriculture and Life Sciences, Univ. of Wisconsin-Madison.
Carolyn DeMoranville and Anne Averill
Cranberry tipworm (Dasyneura vaccinii Smith) lays its eggs in the upright tips of cranberry (Vaccinium macrocarpon Ait.) plants. Feeding damage by newly hatched maggots leads to characteristic cupping of leaves in the upright tip. This damage is readily apparent to growers and has led to concern that damaged tips would not form terminal flower buds for the following season. Insecticide sprays and cultural practices intended to control this insect are generally ineffective. While studying the incidence of return bloom in cranberry uprights (Strik, B. C., et al. 1991. HortScience 26:1366-1367) heavy cranberry tipworm injury with little apparent effect on yield was noted. We initiated a three year study to examine the potential for cranberry plants to recover from tipworm injury and found that cranberry plants recover completely (no effect on flower bud production) from tipworm injury as long as the injury occurs before mid-August. Only 25% recovery from late-season infestations was found. However, such infestations seldom affected more than 5% of the upright tips. Based on our data, we calculated a maximum 6% loss of flower buds to cranberry tipworm in a year of high late-season infestations.
Marianna Hagidimitriou and Teryl R. Roper
Fruit set has been shown to be a major limiting factor in cranberry (Vaccinium macrocarpon Ait.) productivity. Total nonstructural carbohydrate (TNC) content is lowest during the flowering and fruit set period. This research was undertaken to determine the potential sources of carbohydrates which are important to support fruit set and fruit growth in cranberry. Fruiting uprights had lower TNC content than vegetative uprights beginning at early bloom and continuing through harvest, largely due to lower starch content. Starch from fruiting uprights is apparently remobilized to support flowering and fruit set. This also suggests that uprights on which the fruit are borne are the primary source for carbohydrates for fruit set and fruit growth throughout the season. Net CO2 assimilation rates (NAR) were measured in the field on current season and one year old leaves on cranberry uprights. New leaves had higher NAR than one year old leaves throughout the season. Thus, newly formed leaves on uprights, appear to be an important source for carbohydrates for fruit set and fruit growth. On a diurnal basis NAR peaked at approximately 9:00 a.m. and gradually declined through the day.
Justine E. Vanden Heuvel and Martin C. Goffinet
Native to bogs of eastern North America, the American cranberry ( Vaccinium macrocarpon Ait.) is a low-growing, vine-like woody perennial that forms a dense mat on the soil surface ( Eck, 1990 ). Short vertical stems, known as uprights, arise
Bernadine C. Strik and Arthur Poole
1 Associate Professor. 2 Horticultural Extension Agent. Oregon State Univ. Agricultural Experiment Station Technical Paper no. 9884. We gratefully acknowledge the technical assistance of Dawna Jackson and the support of the Oregon Cranberry
Charles F. Forney, Stephanie Bishop, Michele Elliot, and Vivian Agar
Extending the storage life of fresh cranberries (Vaccinium macrocarpon Ait.) requires an optimum storage environment to minimize decay and physiological breakdown (PB). To assess the effects of relative humidity (RH) and temperature on storage life, cranberry fruit from four bogs were stored over calcium nitrate, sodium chloride, or potassium nitrate salts, which maintained RH at 75%, 88%, and 98%, respectively. Containers at each RH were held at 0, 3, 5, 7, or 10 °C and fruit quality was evaluated monthly for 6 months. Both decay and PB increased with increasing RH in storage. After 6 months, 32%, 38%, and 54% of fruit were decayed and 28%, 31%, and 36% developed PB when stored in 75%, 88%, and 98% RH, respectively. The effects of RH continued to be apparent after fruit were removed from storage, graded, and held for 7 days at 20 °C. The decay of graded fruit after 4 months of storage in 75%, 88%, or 98% RH was 10%, 13%, and 31%, respectively, while PB was 12%, 12%, and 17%, respectively. Fresh weight loss decreased as RH increased averaging 1.9%, 1.4%, and 0.7% per month for storage in 75%, 88%, and 98% RH, respectively. Fruit firmness was not affected by RH. Storage temperature had little effect on decay. However, PB was greatest in fruit stored at 10 °C, encompassing 55% of fruit after 5 months of storage. When graded fruit were held an additional 7 days at 20 °C, decay and PB were greater in fruit previously stored at 0 or 3 °C than at 5, 7, or 10 °C. Fresh weight loss increased as storage temperature increased, averaging 0.8%, 1.0%, 1.3%, 1.7%, and 1.9% per month at 0, 3, 5, 7, and 10 °C, respectively. Fruit firmness decreased during storage, but was not affected by storage temperature. To maximize storage and shelf life, cranberry fruit should be stored in a RH of about 75% at 5 °C.