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Fabian Robles-Contreras, Adan Fimbres-Fontes, and Arturo Lopez-Carvajal

Grapes are the most extensively grown crop in the agricultural area of Caborca, Sonora, Mexico (14,000 ha), and water availability is the main limitation of the crop production system. Commonly, grapevines are irrigated with 150–200 cm of water/year. Therefore, it is important to make efficient use of this resource. To demonstrate that the crop criterion (CC) to irrigate is adequate to decrease the water-use efficient, the growers criteria was compared with CC during 1990 and 1991 in a commercial plot of `Thompson Seedless' grapes for wine production grown in a drip-irrigated system. The CC used was: 7.5%, 15.0%, 52.0%, 80.0%, 30.0%, and 7.5% at budbreak state (0–20 days), shoot elongation (21–40 days), fruit set (41–60 days), first harvest (61 days to harvest), during harvest (until 130 days), and postharvest (130–240 days), respectively. Our results indicate that water consumption using CC is 90 cm/year vs. 147–187 cm/year with growers criteria, the use of which did not affect yield.

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Xia Xu*, Zhongbo Ren, and Jiang Lu

Pierce's Disease (PD) is a major factor limiting grape production in the southeast United State. This disease is caused by a bacterium, Xylella fastidiosa Wells et al., which is transmitted to the xylem system of the grapevines primarily by glassy-winged sharpshooters (Homalodisca coagulata Say). Once it is in the xylem, the X. fastidiosa will use the xylem sap as a nutrient source to multiply, colonize, and eventually plug the xylem vessels and cause the PD in susceptible cultivars. On the other hand, symptoms of PD in tolerant cultivars do not appear until fruit maturation, and symptoms are rarely observed in PD resistant cultivars. In order to understand the correlation between X. fastidiosa and PD symptom development, a study was initialed to monitor X. fastidiosa in xylem of resistant, tolerant, and susceptible vines on a monthly basis. Presence of X. fastidiosa was detected directly from xylem sap of field-grown vines by medium culture and confirmed by polymerase chain reaction (PCR). Xylella fastidiosa was detectable throughout the growing season in PD susceptible cultivar `Chardonnay', PD tolerant Florida hybrid grape `Blanc du Bois', and muscadine cultivar `Carlos'. The bacteria were also appeared in the dormant vines with high density in cultivars `Chardonnay' and `Blanc du Bios'. Although X. fastidiosa was also found in dormant canes of `Carlos', the density decreased throughout the late fall and winter months, and they were hardly found before June. The results indicated that X. fastidiosa were carried over from previous season in cultivars `Chardonnay' and `Blanc du Bois', while in PD tolerant cultivar `Carlos', they were newly acquired from the sharpshooter feedings during the growing season.

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Manjul Dutt, Zhijian T. Li, Sadanand Dhekney, and Dennis J. Gray

Genetic transformation of plants necessitates the use of promoters to control transgene expression. Numerous promoters have been isolated from a wide range of organisms for use in plants. However, many of these natural promoters exhibit relatively low activity and/or have limited use. To provide an alternative, we constructed a composite promoter (EP) using a genomic DNA sequence and a 35 bp TATA-containing fragment from the 2S albumin (VvAlb1) gene core promoter of grapevine. The 0.9-kb genomic sequence was identified after TAIL-PCR, based on the presence of several unique cis-acting elements. The sequence showed no homology to any known plant gene, enhancer, and promoter. Two binary vectors, pEP-EGFP/NPT and pEP-GUS, containing a bifunctional EGFP/NPTII fusion gene and a GUS gene, respectively, were constructed to test transcriptional activity of the composite promoter both qualitatively and quantitatively. Transient GFP expression was observed in somatic embryos (SE) of Vitis vinifera `Thompson Seedless' after Agrobacterium-mediated transformation using pEP-EGFP/NPT. Quantitative GUS assay of stably transformed SE containing pEP-GUS indicated that the EP composite promoter was capable of producing GUS activity as high as 12% of that from a doubly enhanced Cauliflower Mosaic Virus 35S promoter or eight times higher than that from a doubly enhanced Cassava Vein Mosaic Virus promoter. In addition, transformation of Arabidopsis with pEP-GUS yielded comparable GUS activity throughout the plant. These data indicate that the EP composite promoter can be used in transformation studies to provide sustained constitutive gene expression in plants.

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Andrew G. Reynolds, Douglas A. Wardle, Brian Drought, and Robert Cantwell

Own-rooted, glasshouse-grown `Chardonnay' vines (Vitis vinifera L.) were planted in a sand medium to which was added one of five levels of granular Gro-Mate (GM), a commercial humate (0, 8, 16, 32, 64 g/pot; 0 to 35 g a.i./pot). Two other treatments consisted of weekly (1× W) or twice-weekly (2× W) applications of liquid GM, whose cumulative addition over the 28 weeks of the experiment totaled 6.7 and 13.4 g a.i., respectively. Shoot length responded to increasing level of GM in a predominantly cubic fashion, with 32 g/pot resulting in the longest shoots. Fresh and dry weights of leaves, shoots, and roots, as well as leaf count and area, exhibited increasing linear or quadratic trends in response to increased level of granular GM. GM increased soil organic matter, K, Ca, Mg, Fe, Mn, Cu, Na, and S and also increased petiole Fe and lamina P, K, and Fe. Liquid treatment resulted in lower soil pH, organic matter, bulk density, and Fe and higher soil conductivity, NO3, P, K, Mg, Cu, Zn, Na, and S than the granular treatments, as well as higher petiole and lamina N and K, lower petiole and lamina P, and lower petiole Zn. Compared to the 1× W treatment, the 2× W produced lower soil bulk density and higher P, lower lamina K, Mn, and Fe; lower petiole Mn; and higher petiole Cu. Plant tissues contained extremely high levels of Mn irrespective of treatment, whereas liquid treatments resulted in high soil NO3 levels. Although liquid GM cannot be recommended for young grapevines under an application regime such as described here, preplant applications of granular GM may have potential for improving growth of young vines in coarse-textured soils. High granular or excessive liquid applications may result in leaf necrosis and retarded growth.

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Lailiang Cheng, Guohai Xia, and Terry Bates

One-year-old `Concord' grapevines (Vitis labruscana Bailey) were fertigated with 0, 5, 10, 15, or 20 mm nitrogen by using a modified Hoagland's solution for 8 weeks during active vine growth in summer. Half of the vines at each N concentration were sprayed with 3% foliar urea twice in late September while the rest served as controls. After natural leaf fall, all the vines were overwintered in a cold room (2 to 4 °C). Four vines from each treatment were destructively sampled before budbreak for reserve N and carbohydrate analysis. The remaining vines were supplied with either no N or sufficient N (10 mm N) from 2 weeks before bloom to 1 month after bloom. All the vines were destructively harvested at 1 month after bloom. Total amount of N in dormant vines increased with increasing N fertigation concentration. Total nonstructural carbohydrates (TNC) increased with increasing N fertigation concentration from 0 to 10 mm, and then leveled off with further rises in N supply. Foliar urea application increased total N but decreased TNC of dormant vines at each given N fertigation level. When no N was provided during the regrowth period, vine total leaf area, fruit yield, and total dry weight increased with increasing N supply from fertigation the previous year. Vines sprayed with foliar urea the previous fall produced a larger total leaf area, a higher yield, and a higher total vine dry weight at each given N fertigation concentration. Providing vines with sufficient N during the regrowth period significantly increased total leaf area, fruit yield, and vine total dry weight across the previous N fertigation concentrations, but vines sprayed with foliar urea still had a larger leaf area, a higher yield, and a higher total vine dry weight at each given N fertigation concentration. Therefore, we conclude that both vegetative growth and fruiting of young `Concord' vines are largely determined by reserve nitrogen, not by reserve carbohydrates, and that current-season N supply plays a very important role in sustaining vine growth and development, especially fruit growth.

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John E. Stenger and Harlene Hatterman-Valenti

A grapevine is generally characterized as a woody vine. However, within the North Dakota State University Grape Germplasm Enhancement Project, a novel determinate natural mutant, with natural self-limited growth and reproductive habit, was

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Andrew L. Thomas, Jackie L. Harris, Elijah A. Bergmeier, and R. Keith Striegler

fan training system described by Zabadal (2002) employed to retain multiple trunks and fruiting canes to increase the likelihood of winter survival of grapevines in cold climates. During the establishment of ‘Steuben’ hybrid grape in Indiana

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Nathan Phillips, Andrew Reynolds, and Frederick Di Profio

Grapevine grafting success has been optimized by enhanced hygiene and storage conditions, HWT, and soaking grafting material in antifungal solutions ( Becker and Hillier, 1977 ). Despite these precautions, poor callus development, inadequate growth

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Matthew Clark, Peter Hemstad, and James Luby

cold-hardy, white wine cultivars Frontenac gris and La Crescent. ‘Itasca’ has more sugar at harvest than ‘Brianna’, another cold-hardy variety with low total acidity levels. Origin The grapevine ‘Itasca’ ( Fig. 1 ) was identified at the Horticultural

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Paolo Sabbatini and G. Stanley Howell

chemistry in cv. Vignoles. Fig 1. Effect of multiple foliar applications of JMS stylet oil (2%, 75 L·ha −1 ) to basal nodes 1 to 6 on non-defoliated ‘Vignoles grapevines’, at trace bloom ( A , Day 1) and at trace bloom and after 3 ( B , Days 1 and 3) and at