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Eric L. Zeldin, Thomas P. Jury, Rodney A. Serres, and Brent H. McCown

The American cranberry (Vaccinium macrocarpon Ait.) was genetically transformed with the bar gene, conferring tolerance to the phosphinothricin-based herbicide glufosinate. Plants of one `Pilgrim' transclone grown under greenhouse conditions were significantly injured by foliar treatments of 100 mg·L-1 glufosinate, although the injury was less severe when compared to untransformed plants. However, the same transclone grown outdoors in coldframes survived foliar sprays of 500 mg·L-1 glufosinate and higher, while untransformed plants were killed at 300 mg·L-1. Actively growing shoot tips were the most sensitive part of the plants and at higher dosages of glufosinate, shoot-tip injury was evident on the transclone. Injured transgenic plants quickly regrew new shoots. Shoots of goldenrod (Solidago sp.) and creeping sedge (Carex chordorrhizia), two weeds common to cranberry production areas, were seriously injured or killed at 400 mg·L-1 glufosinate when grown in either the greenhouse or coldframe environment. Stable transmission and expression of herbicide tolerance was observed in both inbred and outcrossed progeny of the above cranberry transclone. Expected segregation ratios were observed in the outcrossed progeny and some outcrossed individuals demonstrated significantly enhanced tolerance over the original transclone, with no tip death at levels up to 8000 mg·L-1. Southern analysis of the original transclone and two progeny selections with enhanced tolerance showed an identical banding pattern, indicating that the difference in tolerance levels was not due to rearrangement of the transgene. The enhanced tolerance of these first generation progeny was retained when second generation selfed progeny were tested.

Open access

Robert M. Devlin, Bert M. Zuckerman, and I. E. Demoranville

Abstract

The purpose of this study was to test the effect of malathion and IAA on color development in the cultivated cranberry, Vaccinium macrocarpon var. ‘Early Black’. Dosage and time of application were evaluated. Quantitative analyses for antho-cyanins of berries fresh-frozen at harvest showed that applications of 800, 1600, 2400 ppm malathion all caused a highly significant increase in color. Applications of IAA at 30 and 50 ppm did not affect color development. Treated and untreated berries were also analyzed for anthocyanin development after 7 and 14 days in common storage. No significant differences in size or yield were observed between treated and untreated berries. It was concluded that malathion applied 2 weeks before harvest at 1600 ppm would give good color enhancement and still be within the label restrictions for the use of this material on cranberries.

Free access

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.

Free access

Ricardo Cesped-Ruiz* and Bingru Huang

The American cranberry often undergoes drought stress during the summer. However, the physiological response of this species to drought is not well understood. This study was designed to determine the effects of drought on two commercial cranberry cultivars of high potential yield, `Ben Lear' and `Stevens', during a vegetative stage. The plants were subjected to drought for 15 days in a greenhouse. Soil water content, leaf water content, leaf photosynthetic rate, stomatal conductance, transpiration, differential leaf-air temperature, photochemical efficiency (Fv'/Fm') and the actual PSII efficiency (deltaF/Fm') decreased in those plants subjected to drought. Drought reduced differential leaf-air temperature at day 6 of treatment and stomatal conductance and transpiration starting at day 9 and photosynthetic rate at day 13. Drought decreased leaf water content at day 14 and Fv'/Fm' and PSII efficiency at day 15. Our results indicated that cranberry plants in vegetative stage were sensitive to drought for both cultivars and stomatal conductance was the most sensitive parameter among those examined for both cultivars.

Open access

David H. Lees and F. J. Francis

Abstract

The effectiveness of gamma radiation as an enhancer of anthocyanin and flavonol pigment synthesis in cranberries was determined. Three different maturities of cranberries, based on their degree of coloration, and radiation levels of 150 and 300 krad were employed. The changes in the anthocyanin and flavonol pigments were measured quantitatively at regular intervals during storage. Radiation had a beneficial effect on the pigmentation of full-red cranberries and resulted in a significant increase in the anthocyanin and flavonol pigment contents. Effects on the less colored berries were not as great and in some cases flavonoid synthesis was reduced. The radiation induced changes were strictly quantitative in nature and there were no qualitative changes in the anthocyanins and flavonols. The visual effects of radiation on cranberries were minor softening and a stimulation of pigment production in the endocarp area of the fruit, resulting in internal coloration of the fruit. It was concluded that gamma radiation has an effect on the biosynthesis of the pigments involved and that the maturity stage of the cranberries was the controlling factor in determining the degree of response to radiation treatment. A possible mode of action of radiation on flavonoid synthesis was postulated.

Open access

Robert M. Devlin and I. E. Demoranville

Abstract

2-Chloro-2, ‘6’-diethyl-N-(methoxymethyl)acetanilide (alachlor), 4-chloro-5-(dimethylamino)-2-(α,α,α-trifluro-m-tolyl)-3 (2H) pyridazinone (SAN-6706), and 4-chloro-5-(methylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone (SAN-9789) were applied to ‘Early Black’ cranberry vines in the spring at rates of 8, 12, and 16 lb. active ingredient/acre. No phytotoxicity on vine growth or appearance was detected in the alachlor plots or in plots receiving lower rates (8 and 12 lb./acre) of SAN-6706 and SAN-9789 but the higher rate caused a temporary chlorosis at the base of the cranberry leaf blade. No significant differences were detected between untreated and treated berries in respect to yield and berry size, dry wt, pectin content, and anthocyanin development.

Free access

T.R. Roper, A.R. Krueger, C.J. DeMoranville, N. Vorsa, J. Hart, and A.P. Poole

Nitrogen fertilizer application is a universal practice among cranberry growers. Cranberries only use ammonium nitrogen sources. This study was undertaken to discover how quickly cranberries in the field would take up fertilizer-derived ammonium nitrogen. Ammonium sulfate labeled with 15N was applied in field locations in Oregon, Massachusetts, New Jersey, and Wisconsin. Samples of current season growth were collected daily for 7 days beginning 24 hours after fertilizer application. In all cases 15N was detectable in the plants from treated plots by 24 hours following application. Additional nitrogen was taken up for the next 3 to 5 days depending on the location. With the exception of Oregon, the maximum concentration of 15N was found by day 7. Oregon was the coolest of the sites in this research. To determine a temperature response curve for N uptake in cranberry, cranberry roots were exposed to various temperatures in aeroponics chambers while vines were at ambient greenhouse temperatures. The optimum temperature for N uptake by cranberry vines was 18 to 24 °C. This research suggests that ammonium fertilizers applied by growers and irrigated into the soil (solubilized) are taken up by the plant within 1 day following application. Soil and root temperature is involved in the rate of N uptake.

Free access

Carolyn DeMoranville and Joan Davenport

The relationship between yield and applied N in cranberry has been investigated. Cultivar was important in determining optimum seasonal N rate. Sustained production for the hybrid `Stevens' required an annual seasonal total of N at up to 67 kg·ha–1, higher than was optimal for native selections `Early Black' and `Howes'. High N rates were associated with increased fruit rot and vine overgrowth. Optimum N rate varied within cultivar, likely due to variation in soil conditions, but soil N test results have not correlated well with subsequent yield in cranberry. Soil organic matter content can predict potential N release, but plant response must also be taken into account. To refine N rate recommendations, plant characteristics that might predict N requirements/status of cranberry were investigated. A standard of 0.9% to 1.1% N in August tissue has been established for cranberry. To find characteristics that could be used earlier, we surveyed 30 sites for percentage of N in tissue, length of new growth, SPAD chlorophyll meter ratings, fertilizer N use, and yield. Length of new growth could be used as an indicator of cranberry N status from June until bloom, being positively correlated with subsequent yield. The SPAD meter proved to be a viable alternative to in-season monitoring of tissue N during June and July. Readings below proposed standard values indicated the need for N fertilizer if vegetative growth was in the standard range. Thus, the easily determined factors of upright length and SPAD rating could be used to refine fertilizer rates during the active growing season, while tissue testing for percentage of N could be used as a “report card” on the fertilizer program at the end of the season.

Open access

Paul Eck

Abstract

Ethrel at 600 ppm applied as a 200 gal/A preharvest spray to ‘Early Black’ cranberry increased anthocyanin development. Gardner Color Difference Meter readings of fresh fruit indicated that Alar-treated fruit had higher reflectance than control fruits suggesting a delay in surface coloring. Ethrel, Alar, and malathion preharvest sprays did not influence yield or size of the fruit.