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Julie M. Tarara, Paul E. Blom, Bahman Shafii, William J. Price, and Mercy A. Olmstead

Recently, an approach was described for continuous monitoring of growth and estimating yield in grapevines or other trellised crops [Trellis Tension Monitor (TTM); Tarara et al., 2004 , 2005 ]. Briefly, the technique involves continuous

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Imed E. Dami, Shouxin Li, Patricia A. Bowen, Carl P. Bogdanoff, Krista C. Shellie, and Jim Willwerth

threat of freezing stress on grapevines, with the purpose of either changing the meso-climate condition in the vineyard or improving the freeze tolerance of grapevines. Active protection methods include wind machines, heaters, and over-vine water

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Susana Boso Alonso, Virginia Alonso-Villaverde Pilar Gago, José L. Santiago, Mariá C. Martínez, and Emilio Rodriguez

The grapevine cultivar Albariño ( Vitis vinifera L.) has long been grown in northwestern Spain and the north of Portugal. The approval of the Appellation Contrôlée (A.C) “Rías Baixas” denomination in northwestern Spain in 1988 ( Ministerio de

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Thomas J. Zabadal, Gary R. VanEe, Thomas W. Dittmer, and Richard L. Ledebuhr

Functional leaf area is the basis for vineyard productivity. Therefore, the leaf area displayed on a trellis will determine the productive potential of a vineyard. A device that uses a series of infrared sensors was constructed to quantify vineyard trellis fill. A vertical row of sensors on a moving over-the-row vineyard trailer recorded the interception of infrared light beams through the trellis. These values were related to the total time of measurement to calculate a percentage of trellis fill. Our device was used to quantify differences among training systems applied to `Chardonnay' grapevines. This system is quick, easy, and at least as accurate as currently used visual methods. This technique should be useful for determining the influence of various cultural practices on the development of grapevine canopies.

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Gerhard C. Rossouw, Jason P. Smith, Celia Barril, Alain Deloire, and Bruno P. Holzapfel

Grapevine berries are sinks for the incorporation of both carbohydrates ( Davies and Robinson, 1996 ) and N ( Roubelakis-Angelakis and Kliewer, 1992 ) between veraison and fruit maturity. Restricted TNC availability, induced by limited leaf

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Brandon R. Smith and Lailiang Cheng

Chlorosis from lime-induced Fe deficiency limits grapevine ( Vitis L.) growth and productivity ( Bavaresco et al., 2003 ; Gruber and Kosegarten, 2002 ; Mengel et al., 1984a ). As soil pH increases, Fe solubility decreases, and an increase in

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S. Kaan Kurtural, Lydia F. Wessner, and Geoffrey Dervishian

precise regulator of the final crop level in vineyards ( Bernizzoni et al., 2011 ; Geller and Kurtural, 2013 ; Poni et al., 2004 ; Terry and Kurtural, 2011 ). There is agreement in recent literature that attempts to balance grapevine yield with

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R. Paul Schreiner and Carolyn F. Scagel

, 2005b ). Arbuscules in grapevines were also depressed to a greater extent and earlier than was total AMF colonization by ring nematode ( Mesocriconema xenoplax ) feeding, which was linked to reduced root starch levels ( Pinkerton et al., 2004

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W. Keith Patterson and Bruce W. Zoecklein

The relationship between canopy manipulation to improve solar penetration and ethephon application was studied on field-grown Vitis aestivalis L. `Norton' grapevines. Canopy manipulation involved removal of nonfruitful shoots, topping, and application of ethephon (750 mg·liter-1) at two intervals. Vines that were shoot-positioned and topped were not significantly different from control in soluble solids accumulation, but were superior to both ethephon treatments. Potassium levels in grape berries were lower in all treatments than in the control, but malate was significantly reduced only in the 2nd year of the 2-year study. Ethephon successfully controlled vine size and lateral development and thus increased solar penetration into the fruiting zone. Chemical name used: 2-chloroethyl phosphonic acid (ethephon).

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Manjul Dutt, Dennis J. Gray, Zhijian T. Li, Sadanand Dhekney, and Marilyn M. Van Aman

A major drawback to the use of embryogenic cultures for transformation of grapevine is that their ability to undergo genetic transformation is cultivar-dependent. Also, depending on cultivar, embryogenic cultures are difficult to impossible to maintain over time, reducing their utility for use in genetic transformation. An alternative to the use of embryogenic cultures for transformation of grapevine is the use of micropropagation cultures, which are easier to initiate from a wide range of grapevine cultivars and can be maintained over time without loss of function. Vitis vinifera `Thompson Seedless' was used as a model for genetic transformation using micropropagation cultures. In vitro cultures were initiated from apical meristems of actively growing vines and maintained in C2D medium containing 4 μM of 6-benzylaminopurine (C2D4B). Shoot tips and nodes were collected from proliferating in vitro cultures for transformation studies. A variety of wounding techniques, including nicking, sonication, and fragmenting of meristematic tissues was employed in order to enable Agrobacterium infection. We used a construct containing a bidirectional 35S promoter complex with a marker gene composed of a bifunctional fusion between an enhanced green fluorescent protein (EGFP) gene and a neomycin phosphotransferase (NPTII) gene in one direction and a hybrid lytic peptide gene in the other. Transgenic shoots growing in C2D4B medium containing 200 mg·L-1 each of carbenicillin and cefotaxime and 20 mg·L-1 of kanamycin were selected based on GFP fluorescence. Transgenic shoots were rooted and transferred to a greenhouse. To date, 18 transgenic lines have been generated. Details on the transformation procedure will be discussed.