1,721,167 research outputs found
Crop load effects on leaf area evolution and light interception in 'Montepulciano' grapevines (Vitis vinifera L.) trained to 'Tendone' system
No full textThe aim of the study was to evaluate the effect of crop load on leaf area evolution and on the amount of intercepted light. The research was carried out in Southern Italy (N 40° 20’, E 16° 48’) in an irrigated vineyard of ‘Montepulciano’ grafted on 1103 P. Vines, with four canes and about 10-12 buds per cane, were spaced 2.50 x 2.50 m and trained to a ‘Tendone’ system. The vineyard was managed according to the ordinary techniques of the area.
Three levels of crop load were imposed at fruit set: treatment 1 (UT) or unthinned control, with about 70 clusters per vine; treatment 2 (T50), in which
50% of the clusters were thinned and 1 cluster per shoot was retained; treatment 3 (T75) - in which 75% of the clusters were thinned and 1 cluster every two
shoots was retained. Leaf area evolution was evaluated by collecting shoots from mature vines.
Six or eight shoots, randomly chosen from 5 vines, were sampled monthly from 15 days after bud break to the end of September. The following measurements were performed on each shoot: number of stem leaves and lateral leaves, leaf area of stem and lateral leaves, stem and lateral length. Leaf area was measured using a photometric area-integrating meter (LI-COR Model LI-3100, manufactured by Lambda Instruments Corporation).
Transmitted photosynthetic photon flux density (PPFDt) at the base of the canopy (0.2 - 0.3 m above the ground surface) was determined using a linear
PAR Ceptometer (Accupar - Decagon Device, Inc., Pullman, Wash.).
Measurements were taken on three different vines per treatment over the single vine spacing area on a grid of 0.2 x 0.1 m. Incident PPFD (PPFDi) was measured outside of the trees every five minutes. Measurements were taken around noon of sunny days from May to September.
Intercepted PPFD (PPFDin) was calculated for each point of the grid as the difference between PPFDi and PPFDt; diffused and reflected components of
PPFD were not considered.
The preliminary results have shown that vines trained to 'Tendone' system have a high capacity to produce fruits and vegetative organs. Intercepted light reaches a maximum value upon maximum LAI. Significant differences in shoot leaf area and LAI between the three crop load levels were observed
Gestione dell’irrigazione nella fase di post-raccolta in una cultivar di uva da tavola a maturazione precoce.
No full textRisposte preliminari dell'Aglianico del Vulture alla disponibilità idrica del suolo
No full textScopo del lavoro è stato quello di valutare la risposta vegetativa e produttiva delle viti e le modifiche delle caratteristiche tecnologiche di uve “Aglianico del Vulture” a limitate dosi di acqua irrigua ed a diverse modalità di distribuzione. I risultati preliminari, riguardanti le vendemmie 2003 e 2004, hanno messo in evidenza che le caratteristiche vegeto-produttive dell’“Aglianico del Vulture” sono state in parte modificate dalla disponibilità idrica sia in senso produttivo sia in termini di attività vegetativa. Rispetto alle caratteristiche tecnologiche dell’acino, la risposta alla disponibilità idrica ha prodotto differenze significative in termini di peso dell’acino,
contenuto in zuccheri, pH ed antociani estraibili
Response of fruit growth and ripening to crop level in dry-farmed Cabernet Sauvignon on four rootstocks
No full textAn estimate of the amount of clusters that a vine can reasonably bring to maturity is essential for optimizing
crop level. This work was conducted to determine whether the timing of maturity in a high-yielding, dryfarmed
Vitis vinifera L. Cabernet Sauvignon vineyard could be manipulated through rootstocks and crop level. Cabernet
Sauvignon, grafted on 5C Teleki (V. berlandieri Planch. x V. riparia Michx), 1103 Paulsen, 140 Ruggeri, and 110
Richter (V. berlandieri Planch. x V. rupestris Scheele), was used in a trial carried out in 1997 and 1998 in an 8-
year-old vineyard near Oakville, California. Four levels of crop were imposed by winter pruning all vines to fourbud
spurs and cluster thinning at veraison: treatment 1 (100%), or double crop, no thinned vines with ~26 shoots
and 40 clusters per vine; treatment 2 (75%), in which 25% of clusters were thinned; treatment 3 (50%), the standard
crop level in the study area or control, in which 50% of clusters were thinned and one cluster per shoot was
retained; and treatment 4 (25%), in which 75% of clusters were thinned and one cluster every two shoots was
retained. The time required to reach 23.5, 24.0, and 25.0 Brix was linearly dependent on crop level with a rate of
about one day per each ton of grapes. Rootstocks and crop levels had no or little impact on fruitfulness, cluster
and berry size, and final Brix. The reduction in sugar accumulation seems to be a sensitive measure for crop level
and does not appear to be influenced by rootstock or environmental conditions
Berry Size and Yield Paradigms on Grapes and Wines Quality
No full textA key objective of this review is to open a discussion on what we really know
about the effect of berry size and yield on grape and wine quality. Even if berry size
and crop yield are widely recognized as important factors in the quality of resultant
wines, most prior research has shown no effect of yield on wine quality, and the direct
effect of berry size has not been evaluated. Recently, some pruning, thinning and irrigation
experiments were done to test independently for relationships due to size and
yield compared with those due to the normal cultural practices used to control yield
(thinning, pruning and irrigation). Data from these experiments have clearly shown
that these considerated practices affected in an independent way berry size and yield
producing grape and wine of different quality. This renders the generalizations
asserted in both of the paradigms unfounded.
We draw these conclusions about the dependence of composition on yield and
berry size: the viticultural practices used to control yield in a vineyard may be more
important than the yield or berry size values per se in determining the quality of the
resulting grapes and wines
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