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Brent H. McCown and Eric L. Zeldin

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Eric L. Zeldin, Brent H. McCown, Elden Stang, and John Klueh

A project to determine the comparative growth response of micropropagated (MP) and field propagated (FP) cranberry plants was conducted in field plots at a commercial cranberry marsh. Microcuttings were derived from shoot culture and rooted in either plugs or peat pots filled with peat. Replicated 1 m2 plots of MP plants and 15 cm FP cuttings were planted in June. Survival of MP plants after one month was significantly greater than that of the FP plants. Significant growth differences were observed later in the season. The MP plants produced more branches and greater runner elongation, resulting in a much greater ground cover. Many of the FP plants flowered and produced fruit, while the MP plants produced neither. Far fewer new flower buds were set in the fall on the MP plants. Potential advantages of MP cranberries include the fast, uniform establishment of new marshes and consequently earlier achievement of full productivity, and the rapid introduction of new genotypes from breeding or genetic engineering.

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Eric L. Zeldin, David D. Ellis, and Brent H. McCown

Taxol, a promising anticancer drug, is limited by inadequate supply. The production of taxol and related compounds (taxanes) by Taxus tissue cultures has been reported, yet sustained production has not been demonstrated. One theory is that cell differentiation and/or tissue organization is required to sequester taxol and avoid autotoxicity. To investigate this, T. cuspidata shoot cultures were established and the taxane content of various culture stages compared to that of field needles. HPLC analysis identified two peaks which comigrated and had UV spectra identical to taxol and 10-deacetyl taxol. The levels of 10-deacetyl taxol were similar in all samples. Cultured shoots contained much less taxol than field needles, and the level of a third peak which migrates closely to taxol was inversely related to that of taxol. Taxol content was restored in the first flush out of culture. Shoot cultures of T. brevifolia, T. x media, and T. canadensis have also been analyzed. In addition to shoot cultures, nodule cultures, a biological unit that may be suitable for production of taxanes in plant bioreactors, have been initiated and characterized.

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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.