Summer pruning in table grape

This paper reviews cultural practices to improve fruit quality in table grape during vegetative and reproductive seasons. Summer pruning in table grape (Vitis vinifera L.) has more effects than winter pruning, above all with regard to plant productivity and final number of bunches for harvesting. Thinning is one of the most cultural technique and it consists in the elimination of vegetative or reproductive organs in excess. Other summer canopy management techniques include leaf removal, fruit shoots positioning, shoot trimming and girdling

Effetti delle modificazioni artificiali del microclima sulla qualità dell’uva della cv ‘Pinot nero’

Sono stati studiati gli effetti, sulla qualità dell’uva della cv Pinot nero, di defogliazione della zona dei grappoli, effettuata all’allegagione e all’invaiatura, e della copertura della zona dei grappoli con reti di diversi strati e mantenuta sulla fascia produttiva dall’allegagione all’invaiatura, dall’allegagione alla raccolta e dall’invaiatura alla raccolta. I risultati hanno mostrato che gli zuccheri sono diminuiti in relazione alla riduzione precoce di superficie fogliare. Una defogliazione effettuata ad allegagione completata ha determinato un aumento di antociani e flavonoidi. Tuttavia la ricerca ha messo in evidenza il ruolo significativo della temperatura sulla sintesi degli antociani più che di quello della luce ricevuta dai grappoli. L’abbattimento della radiazione solare con la copertura con rete dall’allegagione in poi ha determinato una riduzione della sintesi delle proantocianidine e dei polifenoli totali piuttosto che di antociani. I fenomeni di degradazione di tutti i polifenoli sono stati più intensi nelle tesi defogliate e quando la rete veniva rimossa all’invaiatura

Vegetative and reproductive parameters evaluation of alternative plant material

Dead vines are often a problem in many vineyards and are due to physiological or pathological causes whereby the vines need to be replaced. The replacement operation is a real cost for the direct costs of the plant material, for its planting and for their different management during the current year or in the two years after the replacement, determining also vineyard variability. When replacement is performed in the first years after vineyard establishment it is quite easy, whereas many issues occur when replacement is later, particularly issues considering roots competition. To reduce replacement problems, the use of “alternative plant material” has been evaluated. The “alternative vines” were one year old with a shoot length 80-100 cm and a shoot diameter no less than 7.50 mm. Such plant material has higher producing costs than normal vines, but it has a shorter and easier training period. The use of “alternative vines” also can be a useful tool in varietal changing (in addition to or in replacement of the graft techniques) to obtain a moderate yield since the plantation year. In this case the cost-effectiveness should be evaluated carefully. The research conducted during the 2011 and 2012 growing seasons studied the cultivation techniques adopted in the nursery to obtaining suitable “alternative plant” with different graft combinations. Vegetative and productive parameters of “alternative vines” during the first year of planting were also evaluated. Results suggest different vineyard management compare to the traditional management. Particularly, in the nursery, vines seemed to be more vigorous when there is a greater distance in the row and foliar fertilization is applied. During the first year of planting good vegetative and reproductive performances were shown. When bunches were left on high vigor vines, they ripened properly without negative effects on the vegetation development

MANUAL AND MECHANICAL LEAF REMOVAL IN THE BUNCH ZONE (VITIS VINIFERA L. 'NERO D'AVOLA'): EFFECTS ON PLANT PHYSIOLOGY, VEGETATIVE PARAMETERS, YIELD AND GRAPE QUALITY IN A WARM AREA

Mechanical and manual leaf removal of Nero d Avola vines were carried out in a commercial vineyard in Sclafani Bagni area, Sicily (South Italy), in the 2007 growing season. Rows were North East-South West oriented and vines were spur pruned and non-irrigated. The aim was to investigate the effects of two different ways of defoliation on plant physiology, vegetative parameters, yield and grape quality in a warm temperature area. Fruit zone defoliation consisted of mechanical (MLR) and hand leaf removal (HLR), applied either to both sides of the canopy (Northweast and Southeast). These treatments were applied when the berries had reached pea size and compared to a non-defoliated treatment (control). Hand and mechanical leaf removal caused different and significant reduction in leaf area per shoot modifying leaf-to-fruit ratio. Different vegetative activity was showed among the treatments during the vegetative season (from pea size to harvest). Consequently, differences in canopy architecture were measured at pea size and harvest. Photosynthetic activity of primary leaves was higher in leaf removal treatments than in non-defoliated. In HLR must sugar (°Brix) tended to increase during ripeness process, but at harvest no significant differences among treatments were found. Skin total anthocyanins was lower in HLR and the control vines showed the highest values. Leaf removal had effect on variability between the two canopy sides (Northeast/Southwest) for total anthocyanins and flavonoids. In this study leaf removal at pea size did not modify significantly grape quality of Nero d Avola

EFFECTS OF LIGHT REDUCTION AT BLOOM ON FRUITS SET IN BLACK MAGIC TABLE GRAPES CV IN EARLY AND LATE PRODUCTION CICLES

A shading experiment in ‘Black Magic’ cv was conducted in Sicily to test a new thinning method, aiming to reduce the no. berries/cluster, maximising quality and value of the production. A reduction of intercepted light was imposed at the 65 stage of the BBCH scale (50% cap fall) for 12 days. The soilless greenhouse conditions allowed two growing cycles occurring under different climate conditions, an early (end of March flowering) and a late production cycle (beginning of August flowering). During the shade treatment, net photosynthetic rate was significantly reduced by 82% and 96% in the late and early production cycles, respectively. The sum of flowers and berries dropped in the untreated vines was about 80% in the late and 17% in the early cycle, increasing to 96% and 49% in the shaded vines. This supports the hypothesis that C-starvation during bloom induces berries abscission. As a consequence of the berry number reduction (46.2 and 93.4 berries/bunch obtained in the treatment versus 96.8 and 173.0 berries/bunch in the control, in late and early cycles), the yield dropped to 47.4% and 64.0% of control vines in the late and early cycle. Bunch compactness was also reduced, 5.1 and 10.5 berries/cm of rachis in shaded vines while 8.0 and 15.1 berries/cm of rachis in the control, in late and early production cycle. The no. shot berries was reduced 62.5% in shaded vines in the early cycle. TSS in shaded vines was higher than control in both cycles. Under the viticulture viewpoint, control vines in the late production cycle had already an adequate fruit set, so thinning practice is not economical advantageous. In contrast, in the early cycle control vines produced an excessive no. berries/bunch and a high incidence of shot berries, so, in this case, shading stands for a clear agronomic benefit. The fruit set in ‘Black Magic’ cv can be considered sensitive to incident light reduction at bloom, making shading an effective and successful non-chemical method