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Dong-Yong Choi and Seon-Kyu Kim

Two training systems(open lyre and Kniffin) with two planting densities(3.3 m × 1.5-1.1 m and 1.8 m × 1.5-1.1 m, R × V, respectively) were evaluated for their effects on growth, yield, and fruit quality of fourteen grapes grafted to SO4. Cane pruning weights of vines grafted to SO4 rootstocks averaged 268.1 kg/10a. Chenin Blanc, Cabernet Sauvignon, and Clairette grapes had greater cane pruning weights. Pruning weights of vines trained to the Kniffin system with 1.8 m × 1.1 m spacing were greater. Fruit yields of young vines averaged 438.6 kg/10a, and SV 5276, Carignane, and Ugni Blanc grapes were more productive while Riesling, Grenache, Chenin Blanc, Muscat de Frontignan grapes were less productive. Yields of grapevines trained to the Kniffin system with 1.8 m × 1.1 m spacing were more productive. Fruit quality was less affected by training system and planting density, but significant varietal differences were recognized.

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M. Dolores Loureiro, M. Carmen Martínez, Jean-Michel Boursiquot, and Patrice This

`Albariño' (Vitis vinifera L.) is an important grape cultivar in Spain, morphologically diverse but subject to much misnaming. The objectives of the present work were to correct some of the more common misnamings concerning `Albariño' and to evaluate the genetic variability within this cultivar by analyzing DNA polymorphisms using randomly amplified polymorphic DNA (RAPD) markers and microsatellite techniques. Several accessions of `Albariño' (16 accessions from Misión Biológica de Galicia, one accession from El Encin, one accession from Rancho de la Merced), related cultivars (`Alvarinho', `Caíño blanco', `Cainho branco', `Loureiro'), and cultivars presumably identical to misnomers (`Savagnin blanc' and `Gewürztraminer') were analyzed using 20 RAPD markers and six microsatellite loci. Both techniques revealed polymorphism among `Albariño', `Caíño blanco', `Albariño' from Rancho de la Merced and `Loureiro'. No polymorphism was detected among the 16 `Albariño' accessions from Galicia, the `Albariño' accession from El Encin and `Alvarinho', nor among the `Albariño' accession from Rancho de la Merced, `Savagnin blanc' and `Gewürztraminer', nor between `Caíño blanco' and `Cainho branco'. These results enabled us to clarify the main misnomers concerning these cultivars. The absence of polymorphism among the true `Albariño' accessions did not allow the detection of any clonal variation. The suitability of both techniques for defining the cultivar level for grapevine is discussed.

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Justine E. Vanden Heuvel, John T.A. Proctor, K. Helen Fisher, and J. Alan Sullivan

In order to gain an understanding of the capacity of severely shaded leaves to be productive in dense canopies, the effects of increased shading on morphology, dry-matter partitioning, and whole-plant net carbon exchange rate (NCER) were investigated on greenhouse-grown Vitis vinifera L. `Chardonnay' grapevines. Vines were subjected to whole-plant shading levels of 0%, 54%, 90%, and 99% of direct sun 3 weeks after potting. Data were collected 8 to 10 weeks after potting. Nonlinear regression was used to investigate the relationship of leaf morphological traits and organ dry weights to increased shading. Leaf size was maintained with increased shading to approximately the 90% shading level, while leaf fresh weight, volume, density, and thickness were immediately reduced with increased shading. Root dry weight was most affected by increased shading, and root to shoot ratio was reduced. When nonlinear regressions were produced for light response curves, light compensation point was reduced by approximately 49% by moderate shading, and 61% by severe shading. Shaded leaves approached the asymptote of the light response curve more quickly, and had reduced dark respiration rates, indicating that the morphological compensation responses by the vine allow shaded leaves to use available light more efficiently. However, the long-term ramifications of reduced root growth in the current year on vines with shaded leaves may be significant.

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Terence R. Bates, Richard M. Dunst, and Paula Joy

Three-year-old field-grown 'Concord' (Vitis labruscana Bailey) grapevines were destructively harvested at eight growth stages during 1998 to quantify growth, carbohydrate distribution, and nutrient concentrations of different organs. The roots were the major storage organ for carbohydrates and nutrients, accounting for 84% of the starch and 75% of nitrogen stored in the vines at the beginning of the season. About 78% of the reserve starch in the vine was used for prebloom root and shoot growth. Early-season fine-root growth was a sink for stored vine nitrogen; however, the fine roots quickly became a nitrogen uptake source, providing at least 84% of the spring growth nitrogen. Total root biomass increased from bloom to leaf fall, but reserve carbohydrates and nutrients lost in the prebloom period did not begin to recover in roots until the end of rapid shoot development in late July. Crop removal at harvest, and a late-season root flush, further increased vegetative carbohydrate and nutrient reserves in the short postharvest period.

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Martin C. Goffinet, Mary Jean Welser, Alan N. Lakso, and Robert M. Pool

Northeastern U.S. grape growers have become more knowledgeable about many aspects of grape production, including pruning and training, canopy management, nutritional recommendations, pest and disease management strategies, vineyard floor management, etc. Important to all these aspects is a firm understanding of vine structure and development. Yet, there is no current publication on vine growth and development that growers and researchers can consult to gain an understanding of the organs, tissues, and developmental processes that contribute to growth and production of quality vines in the northeastern U.S. climate. A concerted effort is underway to secure enough information on how vines are constructed, grow, and develop in the northeast so that a publication useful to a wide audience can be produced. Our objective is to consolidate information already on hand that can help explain the internal and external structures of grapevines that are pertinent to the needs of northeast growers, to add information that is lacking by collecting and examining vine parts, and to work toward integrating vine structure with vine physiology and viticultural practices. Over the past decade, organs of various native American, French hybrid, and vinifera varieties have been collected from vineyards at Cornell's experiment stations and from growers' vineyards in the Finger Lakes and Lake Erie regions. Much quantitative data on vine development have been collected and interpreted. Lab work has included dissections of organs, histological and microscopic examination, microphotography, and the production of interpretive diagrams and charts. A list of the subject matter and examples of visual materials will be presented.

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N.K. Dokoozlian

A factorial experiment examined the interaction between chilling temperature (0, 2.5, 5.0, 7.5 and 10 °C) and duration (50, 100, 200, 400, and 800 h) on the budbreak of `Perlette' (Vitis vinifera L.) grapevine cuttings. Cuttings stored at 0 °C exhibited the most rapid budbreak during the first 30 days after being placed under forcing conditions. After this period, chilling temperature had relatively little influence on cumulative budbreak, with cuttings stored between 0 and 10 °C generally exhibiting similar rates of budbreak. In contrast, the slope of the budbreak curves increased, indicating more rapid and uniform budbreak, with increased chilling duration. Significant interactions (P ≤ 0.0001) between chilling temperature and duration were found for both the number of days required for 50% budbreak and total observed budbreak. The number of days required for 50% budbreak declined, while total observed budbreak increased, with increased chilling duration. Within the temperature range evaluated, a minimum exposure of 200 hours was required to achieve commercially acceptable levels of budbreak.

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D.C. Ferree, D.M. Scurlock, and J.C. Schmid

`Seyval blanc' and `Vidal blanc' grapevines (Vitis sp.) grown in large containers were root-pruned at different severities and/or stages of development and the effects on growth of both cultivars and fruiting of `Seyval blanc' were determined. As the severity of root pruning increased, stomatal conductance (g s) and transpiration (E) decreased and the number of wilted leaves increased in both cultivars. In both cultivars, root pruning reduced net photosynthesis (Pn) and E for as long as 18 to 20 days, as well as total leaf area and dry weight of leaves and petioles plus tendrils. The reductions were proportional to the degree of root pruning. A similar pattern existed for cane and root tissue of `Vidal blanc'. As the severity of root pruning increased, berry and cluster weight, and titratable acidity (TA) of `Seyval blanc' decreased. There was no effect of root pruning on berries per cluster, soluble solids content (SSC), or pH of the juice. No interaction was significant for any factor between time of root pruning and fruiting measured on `Seyval blanc' vines. Root pruning at bloom reduced leaf area, number of leaves, and dry weight of petioles, trunks, and canes. Root pruning at veraison had no effect on any vegetative or fruit parameters. Fruiting `Seyval blanc' vines had less leaf area and smaller petiole and cane dry weights than did nonfruiting vines.

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S.J. McArtney and D.C. Ferree

Dormant, 2-year-old, own-rooted `Chambourcin' grapevines (Vitis sp.) were subjected to two levels of root pruning (none, two-thirds roots removed) and were subsequently trained with either one or two canes. Vines were destructively harvested at bloom and after harvest when dormant to determine the effect of stored reserves in the root and competition between shoots for these reserves on vine growth and berry development. Removing 78% of the root system reduced shoot elongation and leaf area more effectively than did increasing the number of shoots per vine from one to two. Root pruning reduced the elongation rate of shoots for 45 days after budbreak, whereas increasing the shoot number reduced the shoot elongation rate for only 20 days after budbreak. A positive linear relationship was observed between leaf area per shoot at bloom and the number of berries per single cluster. These results demonstrate the importance of 1) the roots as a source of reserves for the initial development of vegetative tissues in spring, and 2) the rapid development of leaf area on an individual shoot for high set of grape berries on that shoot.

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A.G. Reynolds, C.G. Edwards, D.A. Wardle, D. Webster, and M. Dever

`Riesling' grapevines (Vitis vinifera L.) were subjected for 4 seasons (1987-90) to three shoot densities (16, 26, and 36 shoots/m of row) combined with three crop-thinning levels (1, 1.5, and 2 clusters per shoot) in a factorial design. Wines were made from all treatment combinations in 1989. Aroma compounds such as trans-3-hexen-1-ol, linalool, and linalool oxides 1 and 2 in many cases decreased in nonaged and aged wines by increasing shoot density and clusters per shoot, while cis-3-hexen-1-ol increased. Aging wines increased concentrations of cis-3-hexen-1-ol, citronellol, α-terpineol, and the linalool oxides, while linalool decreased. Tasters identified aged wines from the lowest shoot densities and clusters per shoot as having the most ripe-fruit flavor and the least green-fruit flavor and perceived acidity. Flavor descriptors were correlated with linalool, cis-3-hexen-1-ol, and linalool oxide 1. Shoot densities of 20 to 25 shoots/m of row are recommended for low to moderately vigorous `Riesling' vines to achieve economically acceptable yields and high wine quality simultaneously.

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R.K. Striegler and G.T. Berg

Grape growers in the southern San Joaquin Valley of California are increasingly concerned about production costs. Reduced demand for wine grapes from this district has resulted in low prices and a decline in grower profitability in recent years. Minimal pruning is a low-cost production system that was developed in Australia more than 20 years ago. This system offers complete mechanization of pruning and harvesting. In general, there is little information available on the use of minimal pruning in California vineyards. The propose of the experiment was to compare the effects of hand and minimal pruning on growth, yield, and fruit composition of `Ruby Cabernet' grapevines. This experiment was conducted in a commercial vineyard near Huron, Calif., during the 1993 and 1994 seasons. Minimally pruned vines had more shoots and fewer mature nodes than hand-pruned vines. Yield and components of yield were also significantly altered by pruning method. Minimal pruning produced the highest yield and number of clusters, while hand-pruning resulted in larger berry weight, cluster weight, and number of berries per cluster. Pruning method did not significantly affect fruit composition.