Sultana Vines Research Articles

The Swing-Arm Trellis for Sultana Grapevine Management

The swing-arm trellis, designed to improve mechanical harvesting of Sultana grapevines used for raisin or wine production and to allow partial mechanization of pruning, is described. The trellis consists of seven wires, i.e. a cordon-wire and three wires each Sf>aced evenly in the horizontal and vertical plane and supported by triangular frames attached to the trellis posts. The vines are pruned to cordons that produce shoots that grow upward and attach to the vertical wires. For use as replacement canes, these shoots are placed horizontally by rotation of the frames. The yield of Sultana vines trained in this way was equal to or better than that of control vines trained in the standard manner with canes twisted around a single wire. Over fo'!r seasons, total yield was 1,31 times more for fresh fruit and 1,25 more for sugar. The yield differences occurred mainly in two seasons and were due to the combined effects of more nodes, better bud burst, more fruitful nodes and, consequently, more bunches. The advantages of managing vines trained on the swing-arm trellis are discussed.

Dormancy and bud burst in sultana vines

Dormancy and bud burst have been studied for sultana vines in the Murray Valley, Australia. The vines are in deep dormancy at the beginning of autumn and the intensity of dormancy decreases gradually during autumn and winter. Bud burst of cuttings taken during the dormant period occurs the more rapidly the higher the temperature at which they are held. There is evidence to suggest that sultanas have no chilling requirement and no clear distinction between organic and enforced dormancy. Treatment with 3 ml of ethylene chlorhydrin in a.201 container for 24 hours is effective in breaking dormancy. The most effective treatment veries slightly with the intensity of dormancy. Removing the outer bud scales or soaking buds in water decreases the intensity of dormancy. The pattern of bud burst found on canes in the field is established on pruned canes at least one month before the shoots appear. Both auxin and gibberellin will delay bud burst and reduce the proportion of buds which burst but auxin will not affect a bud above the point of application whereas gibberellin will do so.

Photosynthesis in vine leaves as a function of light intensity, temperature, and leaf age

Photosynthesis and respiration were measured in the laboratory with an infrared CO 2 analyser using attached leaves on Sultana vines growing either in the glasshouse or out of doors. At light saturation (2,500-3,000 f. c.) the photosynthetic rates approximated 8.5 and 10.5 mg CO/h/dm 2 with light compensation points of 50 and 125 f. c. respectively. The optimum temperature for photosynthesis was between 25 and 30° C. Age effects were examined using shoots from well established field vines. Small but rapidly expanding terminal leaves showed no net photosynthesis but had a high rate of dark respiration and a CO 2 compensation point above 300 ppm. With further expansion the leaves showed a steady increase in photosynthetic activity with a corresponding decline in dark respiration and CO 2 compensation point. The rate of photosynthesis again declined with the onset of senescence.

Production and growth of minimal pruned Sultana vines

Experiments with Sultana vines left unpruned for 15 years or unpruned but skirted to facilitate management (minimal pruned) for 6 years have shown that traditional limits production, particularly in seasons when the district average is high. Minimal pruing increased the production of 50-year-old, non-clonal vines over 6 seasons by about 60 %. They had more bunches (106: 43) and more shoots (275 : 77) but fewer bunches per shoot (0.40 : 0.55) and smaller bunches (231 : 373 g) than pruned vines. At harvest, minimal pruned vines had a canopy similar in size to the pruned vines, and thus a smaller leaf to fruit ratio, (11.6: 17.0 cm 2 ·g -1 ) but still matured the crop. Minimal pruned vines developed into larger vines because only 15 % of the wood was removed at compared to 85 % from the controls but the weight of 1 year-old wood was lower {1.0: 2.3 kg). The shoots of minimal pruned vines were smaller (3.0 : 30.7 g), had fewer leaves (11.0 : 41.1), closer nodes with their mature length regulated by seif pruning (i.e. abscission of non-mature wood). Minimal pruned vines could be hand-harvested but were most suited to mechanical harvesting. Traubenertrag und vegetatives Wachstum von Sultana-Reben bei minimalem Rebschnitt Sultana-Reben blieben entweder 15 Jahre lang ohne jeden Rebschnitt, oder es wurden uber einen Zeitraum von 6 Jahren nur die frei herunterhangenden Triebe auf eine bestimmte Lange zuruckgestutzt, so das die anfallenden Weinbergsarbeiten durchgefuhrt werden konnten (Minimalschnitt). Die Versuche zeigten, das der Traubenertrag durch den herkommlichen Rebschnitt beeintrachtigt wird - besonders deutlich in Jahren mit einem hohen Gebietsdurchschnitt. Der Minimalschnitt steigerte den Ertrag 50jahriger nicht verklonter Reben in den 6 Versuchsjahren um durchschnittlich 60 %. Diese Reben besasen insgesamt mehr Trauben (106 : 43) und mehr Triebe (275 : 77), jedoch weniger Trauben je Trieb (0,40 : 0,55) und kleinere Trauben (231 : 373 g) als die herkommlich geschnittenen Reben. Bei der Traubenernte wies die Laubwand der minimal geschnittenen Reben ahnliche Werte (Blattgewicht, Blattflache, Anzahl der Blatter je Rebe) auf wie jene der normal geschnittenen Reben. Die Relation Blatt : Frucht war infolgedessen verringert (11,6 : 17,0 cm 2 ·g -1 ); trotzdem wurden die Trauben reif. Die minimal geschnittenen Reben entwickelten sich zu groseren Stocken, da beim Rebschnitt nur 15 % des Holzes gegenuber 85 % bei den Kontrollstocken entfernt wurden; das Gewicht des ljahrigen Holzes war jedoch verringert (1,0 : 2,3 kg). Die Triebe der minimal geschnittenen Reben waren kleiner (3,0: 30,7 g), hatten weniger Blatter (11,4: 41,1) und kurzere Internodien, wobei ihre endgultige Lange durch „Selbstschnitt, d. h. Abfallen der nicht ausgereiften Enden, reguliert wurde. Minima! geschnittene Reben konnten von Hand gelesen werden, waren jedoch auch fur die mechanische Ernte bestens geeignet.

Stomatal patchiness of field-grown sultana leaves: Diurnal changes and light effects

Unirrigated, field-grown Sultana vines were used to study diurnal changes of stomatal patchiness under the natural ambient conditions of South Australia. Non-homogenous aperture of stomata (patchiness) was determined by an infiltration technique and by counting infiltrated patches. Stomatal conductance was linearly related to the number of patches with open stomata (r 2 = 0.622). Both parameters increased in the early morning (maxima at 8 a.m.) and decreased thereafter. In the afternoon stomatal conductance and the number of patches with open stomata remained at a low level. When dark adapted leaves were exposed to sun light (900 -1000 mu mol quanta . m -2 . s -1 ) the number of patches with open stomata increased from 23 to 143 cm -2 within 15 min, indicating that besides several stress factors light induces non-homogenous stomatal opening. It is assumed that stomatal action of single patches is autonomous, i.e. stomata of single patches will regulate water loss and CO 2 uptake according to local changes of ambient and endogenous conditions.

Effects of irrigation management and watertable depth on growth and yield of field-grown Sultana grapevines in south eastern Australia

The influence of irrigation amount and frequency of application on growth and yield of Sultana grapevines was studied in a field trial carried out over four years in the Murray Valley irrigation area of Australia. Treatments included low (280mm of irrigation and rainfall), medium (780mm) and high (1300mm) application amounts, each with frequencies of 1, 2 and 4-weekly. Despite artificial drainage, there was a watertable of variable depth: its effect was evaluated by grouping plots into those with shallow (<2.2m depth) or deep (>2.2m depth) watertables. Treatments were applied to grapevines with Sultana scions grafted to Ramsey rootstocks and own-rooted Sultana vines. Yields from vines grafted to Ramsey were largely unchanged by irrigation treatments even where shallow watertables resulted in high soil salinities (ECe>3.0dSm−1), probably because of the capacity of Ramsey rootstock to exclude chloride ions. For vines on their own roots, there were interactions between irrigation frequency and watertable depth for soil salinity and yield, with the fortnightly frequency offering the best compromise where there was a shallow watertable. The response to irrigation amount also depended on watertable depth; the low amount reduced yield relative to that in the medium and high amounts in areas where the watertable was deep but not in areas where it was shallow. Yield in the medium and high amounts tended to be lower in areas where the water table was shallow compared with areas where it was deep. The results suggest that where shallow watertables are present irrigation management should be modified for both own-rooted and Ramsey grafted Sultanas to apply no more than moderate amounts of irrigation and preferably at not less than fortnightly intervals.

Salinity Responses of Grafted Grapevines: Effects of Scion and Rootstock Genotypes

Two-year-old Sultana and Mke vines (Vitis vinifera L.) grafted onto Rupestris du Lot (Vitis rupestris Scheele) and 110 R (Vitis berlandieri Vitis rupestris) were grown in soil, sand, sphagnum peat and farmyard manure mixture (2:1:1:1 v/v) irrigated with 0.3, 2.7 and 5.45 dS m-1 NaCl solutions for a period of 60 days. Biomass accumulation, relative chlorophyll content, leaf water potential, stomatal conductance and transpiration were significantly reduced by salinity in all graft combinations. The inhibiting effect of salinity on growth varied according to the characteristics of the scion genotype and the level of salinity. The results imply the predominance of the scion genotype in determining variation in the leaf-level physiological characteristics of grafted vines because stomatal conductance and transpiration were higher in Sultana than in Mke at the same leaf water potential and the level of salinity, regardless of the rootstock genotype. NaCl treatments did not affect leaf Cu concentration while inducing significant Na, K, Ca, N, P, Mg, Fe, Mn and Zn elevations in the leaves of all scion/rootstock combinations. While salinity caused an increase in N content and a decrease in K content in the roots of all graft combinations, it had no influence on Ca, P, Cu and Zn concentrations. In contrast to the Sultana grafted vines, NaCl salinity led to a decrease in Mg, Fe and Mn concentrations in the roots of Mke grafted vines. Nevertheless, ion accumulation in leaves and roots of grafted vines under saline or non-saline conditions was controlled predominantly by the genotype of the scion. In response to salinity, Sultana grafts accumulated higher amounts of ions in their leaves than in their roots. However, in Mke, higher ion concentrations were seen in the roots. Therefore, the increase in the transport of inorganic ions up to the leaves seems to be the major component of osmotic adjustment in salt-stressed Sultana vines.

Response of grapevines to irrigation-induced saline–sodic soil conditions

The responses of grapevines (Vitis vinifera L.), ungrafted and grafted to Ramsey rootstock, to saline irrigation have been investigated in drip-irrigated trials at Loxton, Dareton and Merbein in the Riverland–Sunraysia region of the southern Murray–Darling Basin. Soil type and climate were similar across the sites and the characteristics of the soils were monitored in relation to salinity treatment. The treatments involved application of defined irrigation water salinities throughout the season at Merbein and Dareton, while at Loxton, a high salinity treatment was applied between flowering and veraison with low salinity being applied in the remainder of the season. Between-site comparisons of the same rootstock or same cultivar in the fifth season of irrigation show that for water of similar salinity (volume weighted electrical conductivity of 1.4–1.6 dS/m), the ion accumulation patterns were not equivalent. Leaf petiole sodium ion (Na+) and chloride ion (Cl–) concentrations in ungrafted Sultana vines at Dareton were 2-fold those at Merbein, which aligned with differences in electrical conductivity of the soil saturation paste extract. Differences between salinity of soil and ion content of leaves at the 2 sites were attributed to different irrigation management with the estimated leaching fraction at Merbein nearly double that at Dareton. The average ECe at Loxton was equivalent to that at Merbein. However, the leaf lamina Cl– in vines grafted to Ramsey rootstock at Loxton was 2-fold that at Merbein and leaf lamina Na+ was 10-fold. Cultivar differences between the 2 sites — Sultana at Merbein and Colombard at Loxton — may explain a small part of the increase in leaf Na+ and most of that in leaf Cl–. However, a far more plausible explanation is that vines at Loxton experienced transient waterlogging which increased their uptake of both Na+ and Cl–, and increased the rate of Na+ uptake relative to that of Cl–. Transient waterlogging was probably caused by a combination of soil sodicity, small excesses in irrigation, and the combination for part of the season of low electrolyte concentration and high sodium adsorption ratio in the soil solution. Under waterlogged conditions, the uptake of Na+ relative to Cl– at Loxton would have been further enhanced by the inherent differences between Loxton and Merbein in the properties of the soil solution. The soil solution at Loxton had a higher Na:Cl ratio.

Response of Sultana vines ( V. vinifera L.) on six rootstocks to NaCl salinity exposure and recovery

One-year-old Sultana ( Vitis vinifera L.) vines, own-rooted and grafted on 41B, 110R, 140Ru, 1103P and SO 4 were grown in sand–perlite mixture (1:1) irrigated with half-strength nutrient solution containing 5, 25, 50 and 100 mM of NaCl. Growth, tissue mineral content and leaf gas exchange response to salt treatment and subsequent recovery were examined over a 70-day period. Shoot growth, leaf area and total dry weight were significantly reduced ( P<0.05) at all salinity levels. Tissue salt content increased significantly with increasing salinity, Cl − being always higher than Na +. Photosynthetic rate ( P n) and stomatal conductance ( g s) were greatly reduced by salinity and highly correlated with leaf Cl − content. Own-rooted vines exhibited higher dry matter production and photosynthetic rates than grafted vines, despite the higher Cl − and Na + content. During recovery, vines previously treated with 50 and 100 mM NaCl exhibited photosynthetic rates and stomatal conductances similar to the control, although laminae Na + and Cl − content continued to increase. Our results showed that own-rooted ‘Sultana’ vines ( V. vinifera) can cope better with high salinity followed by those grafted on 1103P, 140Ru, 110R, SO 4 and 41B rootstocks.

A basic peroxidase isoenzyme from the grape pedicel is induced by gibberellic acid

Soluble peroxidase activity from pedicels of seedless table grape cv. Sultana was highly stimulated by post-bloom applications of gibberellic acid (GA3) to vines. The increase in peroxidase activity was mainly due to the induction of a basic peroxidase isoenzyme (pI &gt; 9; BPrx-HpI). The activity of two other peroxidase isoenzymes of pI 6.5 and 3.2 was not altered by the hormone treatment. BPrx-HpI was induced by GA3 in pedicels and rachis but not in berries, although in berries peroxidase activity was also stimulated by post-bloom GA3 applications. BPrx-HpI oxidised guaiacol and ortho-phenylenediamine (o-PDA), while the others peroxidases found in the pedicel and in the berry oxidised only o-PDA. Hence, BPrx-HpI was characterised as a guaiacol-peroxidase showing no activity towards ascorbic acid (ASC). The possible role of BPrx-HpI in pedicel lignification and berry-drop caused by GA3 applications to cv. Sultana vines is discussed.

Biosynthesis of flavour compounds in Muscat Gordo Blanco grape berries

Inflorescences of the floral grapevine cv Muscat Gordo Blanco (syn. Muscat of Alexandria) were grown on their own shoots until maturity or, after approach-grafting before flowering, on the shoots of the non-floral cv Shiraz (in the glasshouse) or Sultana (in the field). The flavour compounds of their berries were compared with those in the berries of the non-floral cultivars, grown either on their own shoots or, by grafting, on the shoots of the Muscat cultivar. For this, monoterpene glycosides were isolated from the fruits, enzymatically hydrolysed and the released monoterpene aglycons were liquid-liquid extracted and analysed by GC-MS. The Muscat Gordo Blanco berries of ungrafted bunches and of bunches grafted onto Shiraz or Sultana vines yielded fruit with monoterpenes at levels and types typical of this floral grape variety. The berries of Shiraz and Sultana bunches contained only low levels of monoterpene glycosides both on their own shoots or grafted onto Muscat shoots. The lack of difference between flavour compounds in grafted and non-grafted fruit indicate that aroma compounds are synthesised in the berries and that their presence is determined by the genotype of the grape bunch rather than by the genotype of the vine.

Comparative study of vine morphology, growth, and canopy development in cane-pruned and minimal-pruned Sultana

The seasonal development of vine canopy size and vine morphology of minimal- and cane-pruned Sultana was examined by destructive harvests during the 1982-83 growth period. Leaf canopies of minimal-pruned vines developed more quickly, grew larger, and filled sooner than those of cane-pruned vines. Minimal-pruned vines had 4 times the number of shoots and 3 times the number of nodes on current seasons's shoots at 34 days after budburst. This largely explains the more rapid canopy development and fill of minimal-pruned vines. Minimal pruning had a stunting effect on growth, resulting in shorter shoots, shorter internodes, and smaller leaves compared with cane pruning. Indirect optical measurements of the seasonal leaf canopy development of Sultana vines in the same experimental vineyard during the 1991-92 growth period confirmed the results obtained in 1982-83.

Effects of waterlogging, rootstock and salinity on Na, Cl and K concentrations of the leaf and root, and shoot growth of sultana grapevines

Potted Sultana vines ( Vitis vinifera L. cv. Sultana) on own-roots or grafted onto Ramsey, Harmony, Schwarzmann or 1613 rootstocks were irrigated with solutions containing 1, 10, 20, 40 or 60 mM NaCl. Half the vines had free-draining rootzones and the other half were waterlogged for the first week in a 2-week cycle. The vines were harvested after seven cycles. Raising the irrigation salinity from 1 to 60 mM caused growth to decline by 47% in vines with free-draining rootzones and by 61% in vines with waterlogged rootzones. Under saline conditions, the use of chloride excluding rootstock reduced leaf chloride concentration by 60% in vines with free-draining rootzones but by only 18% in vines with waterlogged rootzones. Waterlogging decreased the root chloride concentration in all rootstocks. The leaf potassium concentration was reduced by waterlogging at irrigation salinities less than 20 mM NaCl and increased by waterlogging at higher salinities. Waterlogging altered the relative effects of rootstock on leaf potassium.

Evaluation of an Improved “Wetting Machine” for Applying Emulsion to Dry Sultanas on Trellises

An experimental wetting machine was designed and developed to investigate the effect of nozzle settings, nozzle pressures, machine ground speed, and volume of drying emulsion applied on the volume of spray retained on the vines and the quality of fruit produced. Trials were conducted in 1991 and 1992 on Sultana vines trained on a Marshall Trellis. The trials concluded that the quality of fruit produced varies with the volume of drying emulsion applied to the vines, and the volume of drying emulsion retained by the vines is independent of nozzle settings, nozzle pressures, ground speed, and the volume of drying emulsion applied within the range of the trials.

The Effect of Transient Waterlogging on the Growth, Leaf Gas Exchange, and Mineral Composition of Potted Sultana Grapevines

Potted Sultana vines were waterlogged for the first 0, 1, 3, 5, or 7 days of a two-week cycle designated W0, WI, W3, W5, and W7, respectively. The vines were harvested at the end of the fourth cycle. Shoot elongation rates over the first two cycles for W0 to W7 were 56, 51, 34, 38, and 35 mm/day, respectively. Vine leaf and stem dry weights at harvest were 37, 32, 22, 21, and 19 g/vine for W0 to W7, respectively. Photosynthesis and stomatal conductance were reduced both during and following waterlogging, but leaf water potential was unaffected. Waterlogging reduced leaf blade N. P, and Ca, increased Na and Mg, and did not affect K, Cl, Mn, Zn, and N-N0₃.

Influence of rootstock and trellis systems on the productivity of Sultana grapevines

Sultana vines, either own-rooted or grafted to Dog Ridge or Ramsey rootstocks, were trained to 4 trellis systems: 0.3-m narrow T, 0.9-m wide T, arch cane, swing-arm. The swing-arm trellis generally gave the highest yields over the 9 years of the trial. Average annual yields were 19.5, 22.0, 15.6, and 26.2 kg/vine (1442 vines/ha), respectively, for the 4 trellis systems. Vines grafted to Ramsey rootstock had higher overall yields than own-rooted vines and vines grafted to Dog Ridge rootstock (24.0 v. 20.8 v. 17.8 kg/vine). The yield advantage conferred by Ramsey rootstock was greatest in years 1-3 of the trial. There was no significant trellis x rootstock interaction. Trellis effects on yield were primarily due to effects on bunch number, while rootstock had a greater effect on berry and bunch weight. Grafted vines were less fruitful than own-rooted vines. There was no significant difference in quality of fruit dried in a dehydrator, but when fruit was trellis-dried, quality was higher for the swing-arm than for the wide T-trellis, with the other trellises intermediate. Own-rooted vines produced better quality trellis-dried fruit than did vines grafted to Ramsey rootstock. The swing-arm trellis was not well suited to commercial production, but it produced good yields and had other desirable characteristics that are incorporated in some new trellis systems being developed in major dried vine fruit production areas in Australia.

Effect of potassium and nitrogen supply on the distribution of minerals and organic acids and the composition of grape juice of Sultana vines

Fruiting Sultana vines grown under glasshouse conditions were supplied with 2 K+ levels (0.05 or 0.15 g K+/week) and fertilised with either NH4+ [as (NH4)2SO4] or NO3- [as Ca(NO3)2] as a nitrogen source. Enhanced K+ supply (0.15 g/week) increased K+ concentration in laminae by 1896, in petioles by 59% and in stems by 23%, and reduced Mg2+ of laminae and petioles by 18 and 24% respectively, while Ca2+ was not effected. K+ supply had no effect on tartrate or malate concentration in laminae, stem or roots. Use of NO3- instead of NH4+ as a nitrogen source led to 220% higher citrate and 168% higher malate concentrations in laminae. In roots NO3- supply caused 61% higher citrate, 41% higher tartrate and 26% higher malate concentrations. Higher K+ fertilisation (0.15 g/week) had no effect on fruit yield or sugar content, but increased grape juice pH from 3.95 to 4.08, malate concentration from 0.94 to 1.20 g/ L and K+ concentration from 46.8 to 56.8 mmol/L, thereby causing lower grape juice quality.

Comparison of trellises and pruning levels for Sultana vines in the Murray Valley

Five trellising systems for irrigated sultana vines under conventional district spacing have been compared in a field trial at Mildura, Victoria. They were 'narrow T', 'narrow T, one foliage wire', 'narrow T, two foliage wires', 'narrow double T' and 'wide T'. For the first two years of the trial, pruning was to six 14-node canes for each vine, then for the next four years three levels of pruning were imposed on the trial as split-plot treatments-'severe'' (as before), 'medium' (averaging about eight 14-node canes) and 'light' (averaging about ten 14-node canes). There were no differences in yield due to the trellising treatments until differential pruning was introduced. Then there were significant differences in dried fruit yield due to trellising, regardless of pruning, in the two good harvests, and due to pruning in all four seasons. Overall the two best treatments were 'light' pruning with 'narrow T, two foliage wires' or with 'wide T', both yielding a quarter more than the conventional 'severe' pruning with 'narrow T'. The differences are seen as due to more bunches per vine with 'light' pruning, and to the ability of 'narrow T, two foliage wires' and of 'wide T' to support without crowding the greater number of bunches put down.

Carbon Balance of the Sultana Vine (Vitis vinifera L.) And the Effects of Autumn Defoliation by Harvest-Pruning

Components of the carbon balance in the Sultana vine (Vitis vinifera L.) were examined with emphasis on the autumn, post-harvest, period. The net photosynthetic rate (PN) of leaves decreased from 0.30 to 0.03 mg CO2 m-2 s-1 from January to May (late summer to autumn). Two-thirds of this decline cocurred in the month before leaf fall. This decline in PN as senescence progressed was mainly due to increases in the 'residual', non-gas-phase, resistance to CO2 transfer. 14C-labelled assimilates were shown to move from the leaves to the perennial portions of the vine in both early and late autumn, and this 14C label reappeared in the shoot growth of the following spring. However, the level of carbohydrate reserves in shoots, roots or trunk in the autumn to spring period was not significantly affected by a severe (c. 60%) defoliation in early autumn. This level of defoliation, which the vine is able to tolerate without cumulative effects, occurs where Sultana vines are 'harvest-pruned' as part of the harvesting method of trellis drying.

Pruning Sultana vines by the arched cane system

Pruning Sultana vines in the Murray Valley by the system of 'arched canes' is described. In two experiments there were trends towards slight increases in crop despite smaller bunch weight when the canes were arched downwards instead of wrapped tightly around thetrellis wire. Downward arching did not greatly affect overall vine performance, but it modified the distribution of growth and yield along the canes, leading to more bunches on the middle part of the cane and shorter shoots on the distal part of the cane. Arching the canes upwards gave similar results to wrapping and showed no commercial promise. Harvest pruning was somewhat faster when the canes were arched downwards, but there was no quality difference in the trellis dried fruit. Winter pruning was speeded up by up to one-half of normal pruning time when the canes were arched, particularly when clips were used to attach them to the trellis wire. Vines pruned by arching had sufficient replacement canes although they produced fewer mature shoots near their crowns than vines pruned by wrapping. It is concluded that pruning Sultana vines by arching canes downwards leads to several beneficial changes, i.e. reduced bunch weight without loss of crop, less fruit clumping where the canes of two adjacent vines meet, shorter terminal shoots, and reduced pruning time. This can be achieved without major changes of the trellis.