Carbohydrate supply has been hypothesized to limit fruit set in cranberry (Vaccinium macrocarpon Ait.), however the limitations to carbon gain throughout the season are currently unknown. These experiments investigated the effects of light, temperature, fruit presence, and defoliation on carbon production and partitioning in potted cranberry. Fruiting and vegetative uprights (short vertical stems which bear fruit biennially) reached similar asymptotes with respect to light response, but fruiting uprights reached saturation at a lower light intensity than vegetative uprights. Runners (diageotropic vegetative stems) had a lower asymptote, higher light compensation point, and greater rate of dark respiration than uprights. Temperature had little effect on net carbon exchange rate of uprights or runners. Before new growth, defoliation did not affect the concentration of total nonstructural carbohydrates in the vegetative uprights, or the partitioning of soluble carbohydrates to starch, even though uprights with lower leaf areas had higher net CO2 assimilation. At fruit set and again at fruit maturity, defoliation reduced total nonstructural carbohydrate concentration, while net CO2 assimilation was not affected. Carbohydrate production and partitioning within an upright was unaffected by the presence of a single fruit throughout the experiment.
Justine E. Vanden Heuvel and Joan R. Davenport
Eric Hanson and Annemiek Schilder
Twenty cranberry (Vaccinium macrocarpon) genotypes were evaluated for five seasons in an experimental upland planting in southwest Michigan. Beds were constructed on a silty clay loam soil by excavating to grade, and filled with 30 to 45 cm of sand. Four 2 × 2-m plots of each genotype were planted in 1996. Fruit were harvested with hand scoops from 2000 to 2005. Yield per plot, average berry weight, and percent berries exhibiting decay were determined. Sound fruit were also stored at 2 °C for 4 to 8 weeks and sorted to determine the percentage of fruit developing decay in storage. Fungi were isolated and identified by morphological characteristics. Genotypes producing the highest average yields were `Stevens', `Ben Lear', #35, `LeMunyon', and `Franklin'. Varieties with the highest average berry weight were `Pilgrim', `Stevens', `Baines', `Beckwith', `Searles', and #35. Genotypes with lower rot incidence at harvest were #35, `Early Black', and `Foxboro Howes', whereas `Howes' and #35 developed the least rot during storage. Fungi commonly isolated from decaying fruit were Colletotrichum sp., Coleophoma empetri, Phomopsis vaccinii, Phyllosticta vaccinii, Fusicoccum putrefaciens, Botrytis cinerea, Pestalotia sp., and Allantophomopsis sp. Prevalence of specific fungi differed among cranberry genotypes.
Justine E. Vanden Heuvel
Flooding is often used as a pest management tool in cranberry production. The “Late Water” flood is a 1-month flood held on some Massachusetts bogs from mid-April to mid-May, and has anecdotally been related to poor vine performance. The flood was simulated at 11 °C and 21 °C on potted cranberry uprights (cv. Stevens). Over the course of the 1-month flood, total nonstructural carbohydrate concentration (TNSC) of the upright tissue decreased by 23% and 50% in the 11 °C and 21 °C treatments, respectively. Decreases in upright TNSC in the 11 °C treatment were mostly due to a substantial decrease in sucrose, while in the 21 °C treatment, sucrose, glucose, fructose, and starch all decreased significantly over the course of the flood. The greatest decrease in upright TNSC in the 11 °C treatment occurred during the first week of the flood, while in the 21 °C treatment, the greatest decrease occurred during the fourth week. Root TNSC was not affected by flooding in the 11 °C treatment, but was reduced by 39% in the 21° C treatment. Two weeks following removal from the 1-month flood, uprights in the 11° C treatment contained 9% more TNSC than uprights in the 21 °C treatment, while root TNSC from the two treatments was similar. No temperature treatment differences were evident in the uprights or roots by harvest.
Justine E. Vanden Heuvel*
Fruiting and vegetative greenhouse-grown cranberry uprights (Vaccinium macrocarpon Ait.) were subjected to four defoliation levels (0%, 25%, 50%, 75%) on one of three dates during the growing season. Seven days following defoliation, vines were destructively harvested and carbohydrate concentration was quantified using HPLC. Prior to new growth, defoliation did not affect the concentration of total non-structural carbohydrates (TNSC) in the uprights, or the partitioning of water-soluble (i.e., sucrose, glucose, fructose) to ethanol-insoluble (i.e., starch) carbohydrates, even though uprights with lower leaf areas had higher net CO2 assimilation rates (A). At 2 weeks post-bloom, TNSC concentration was reduced in defoliated vines, although A was not affected by defoliation. Prior to harvest, TNSC concentration was reduced in vines subjected to defoliation while A was unaffected, although the positive relationship between soluble carbohydrate concentration and leaf area per upright reached an asymptote, while the direct relationship between starch concentration and leaf area remained linear. Carbohydrate production and partitioning of an upright was unaffected by the presence of a single fruit throughout the experiment. These results suggest that carbohydrate production in cranberry uprights may be sink-limited prior to fruiting, and then becomes source-limited as the growing season progresses.
Joan R. Davenport
To examine the impact of N fertilizer rates and timing on cranberry (Vaccinium macrocarpon Ait.) yield and the fruit quality factors total anthocyanin, average berry weight, and field and storage rot, plots were established for 3 to 4 years. The cranberries received a total of 0, 22, or 44 kg N/ha over the growing season applied in three, four, or five applications, which varied by growth stage. There were eleven possible treatment combinations in Massachusetts on `Early Black' and `Howes' and in Wisconsin on `Stevens' and `Searles', and seven possible treatments in New Jersey on `Early Black' and in Washington on `McFarlin'. The results showed a nationwide response to N that suggests the experimental middle rate of 22 kg·ha-1 would result in high yields with moderate rot. However, the best timing for applying the fertilizer varied by both state and cultivar, where three late season applications were best on `Early Black' in New Jersey versus four early season applications on the same cultivar in Massachusetts, and applying N fertilizers across five applications was optimal for `Stevens' in Wisconsin.
R.G. Novy, N. Vorsa, and K. Patten
Ocean Spray Cranberries, Inc. We thank P. Smouse for assistance in statistical analyses and F. Caruso and I. Demoranville for providing `McFarlin' samples from Mass. The cost of publishing this paper was defrayed in part by the payment of page charges
With dwindling funding for horticultural research, the need to conduct experiments which are the most efficient in terms of resource (including personnel) utilization becomes apparent. Research on minor crops such as cranberry (Vaccinium macrocarpon, Ait.) has been particularly hard-hit by the funding crunch. A study to generate a large database as the basis for future experimental design was initiated in 1986 for the variety `Early Black' (60% of MA commercial acreage). Seasonal nutrient levels for all tissues, patterns of biomass development, components of yield, and fruit development were included. In 1989, the study was expanded to include a comparison of 6 MA varieties grown under the same cultural and environmental condition. A portion of the database will be presented and its implementation to increase field experiment efficiency will be discussed.
S. Y. Wang, J. L. Maas, E. M. Daniel, and G. J. Galletta
Ellagic acid (EA) a naturally occurring polyphenol in many fruit and nut crops, is a putative inhibitor of certain chemically-induced cancers. Improved methods of extraction, detection and quantification are essential for accurate determination of EA for plant physiological and genetic studies and animal nutrition and chemopreventative studies. Column (C18) preconditioning significantly reduced column retention of EA. An ammonium phosphate/methanol solvent system was used in preference to sodium phosphate/methanol. Fruit sample determinations were 10-100 times higher than previously reported, due to the improvements in efficiency of these methods. EA levels (mg/g dry wt) were: strawberry pulp (1.55), achene (8.46), root (1.55), crown (3.32) and leaf (14.27); blackberry pulp (,2.43) and seed (3.37); and cranberry skin (1.06), pulp (0.31), seed (0.69), leaf (4.10).
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.
K.D. Patten and J. Wang
Percentage of fruiting uprights, fruit set, number of fruit per upright, and flower bud formation of `McFarlin' and `Stevens' cranberries (Vaccinium macrocarpon Ait.) were reduced by removal of old leaves, new leaves, or both on the upright. Results varied slightly, based on which leaves were removed, time of removal, cultivar, year, and bog site. Percentage of fruiting uprights, flowers and fruit per upright, and fruit set were higher on uprights with a terminal bud size >1 mm in diameter in September than for those <1 mm in diameter. Effects were cultivar and site dependent. Terminal bud size of `McFarlin' was negatively related to the subtending number of fruit and positively related to leaf fresh weight of the upright.