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Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 1/8
Ref: C0354
Crimson Seedless table grape grown under plastic film:
ecophysiological parameters and grape characteristics as
affected by the irrigation volume.
Giuliano Vox, Evelia Schettini and Giacomo Scarascia Mugnozza, Department of Agricultural
and Environmental Science (DISAAT), University of Bari, via Amendola 165/A, 70126 Bari,
Italy
Luigi Tarricone and Giovanni Gentilesco, Consiglio per la Ricerca e la Sperimentazione in
Agricoltura, Unità di ricerca per l’uva da tavola e la vitivinicoltura in ambiente mediterraneo,
via Casamassima 148, 70010 Turi, Bari, Italy
Laura de Palma, Department of Science of Agriculture, Food and Environment (SAFE),
University of Foggia, via Napoli 25, 71122 Foggia, Italy
Abstract
Plastic films used to cover vineyard change microclimate conditions aiming to advance or
delay grape maturity according to the table grape marked demand. The capacity of the cov-
ering materials to modify the greenhouse microclimate strongly depends on their radiometric
properties. The aim of this paper is to study the effect of three watering regimes and of the
radiometric characteristics of plastic film used to delay harvest of Crimson seedless table
grape grown in the Apulia region (Southern Italy). Crimson Seedless vines trained to
“tendone” trellis system were irrigated with different water regimes, from berry set to one
week before harvesting, corresponding to about 50% (WR1), 100% (WR2) and 80% (WR3)
of water lost by evapotranspiration. After veraison, Crimson Seedless vines were covered
with plastic film until grape harvest. Laboratory tests were carried out on the new film in order
to evaluate the radiometric properties. Vine water status and leaf gas exchange were as-
sessed. At harvest, the yield components and the grape characteristics were analyzed. Vine
water status measured under midday conditions showed a moderate improvement for WR3
and WR2 treatments, but leaf temperature decreased and leaf gas exchange increased in
WR3 vines. Water availability significantly affected berry growth, inducing the lowest cluster
weight in the treatment WR1 that received the lowest watering volumes; also berry diameters
were significantly affected by the irrigation treatments. Crop water productivity (grape produc-
tion per unit of applied water) decreased from WR1 to WR2 and WR3. The greatest water
deficit reduced significantly the total pruning weight per vine, that is an indicator of the vege-
tative vigor.
Keywords: radiometric properties, water deficit, leaf gas exchange, crop water produc-
tivity, pruning weight
1 Introduction
Covering the vineyard with plastic film is a technique largely adopted in Southern Italy in or-
der to advance or delay the ripening of table grapes according to marked demand. Grape
yield, precocity or delay, and quality depend on the variety, the cover management and the
radiometric properties of the plastic film used to protect the vineyard (Novello et al., 2000).
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 2/8
The capacity of the covering materials to modify the greenhouse microclimate strongly de-
pends on their radiometric properties. For agronomical purposes a covering film must have a
high transmission of the photosynthetically active radiation (PAR) and a low transmission of
long wave infrared radiation (LWIR). Plastic covering films are also used to protect vineyard
against rain, hail, spring frost, and wind, in order to enhance berry growth and to obtain a
more uniform skin color.
Table grape growing needs irrigation water supply in order to get a satisfying grape yield and
bunch quality. Today there is a renewed interest about deficit-irrigating table grape vines
(Ezzahouani and Williams, 2007, Du et al., 2008, El-Ansary et al., 2005) stimulated in large
part by the attention to climate change and their impact on agriculture (Schultz, 2000).
Crimson Seedless is a late-season red seedless table grape variety developed by David
Ramming and Ron Tarailo of the USDA Fruit Genetics and Breeding Research Unit, Fresno,
(Dokoozlian et al., 2000). This grape has superior eating characteristics, firm and crisp berry
texture and excellent flavour. The cluster is conical with a shoulder, medium in size, with av-
erage length and weight of about 0.5 kg and 20 cm, respectively. The natural berry has cy-
lindrical to oval shape, medium size, and the following average carpometric traits: length 20.8
mm, width 16.6 mm, weight 4.0 g. The vine is vigorous and leafy, as it often occurs with
seedless grapevine varieties.
In the Apulia region, Crimson Seedless vineyards are trained to “tendone system” and more-
over, starting from the stage of berry veraison, they are covered with plastic films in order to
delay the harvesting up to the Christmas period. Thanks to this technique Crimson Seedless
contributes to extend the availability of fresh table grapes from October up to the winter sea-
son (de Palma et al., 2005; Tarricone et al., 2005).
The aim of this paper is to study the radiometric characteristics of a plastic film used to delay
the grape harvesting, as well as the effects of three irrigation regimes on the vine
ecophysiological performance and on the grape yield and quality, in cv. Crimson Seedless
grown in Southern Italy.
2 Materials and methods
2.1 The field test
The field test was carried out at a commercial vineyard located in the Apulia region, Southern
Italy (Castellaneta Marina, Taranto, latitude 40° 37’ N, longitude 16° 56’ E, 45 m a.s.l.) during
the 2011 season. Vitis vinifera cv. Crimson Seedless was grafted onto 140 Ruggeri rootstock
and trained to “tendone overhead trellis”, with a plant density of 1379 vines ha
-1
(2.50 m x
2.90 m apart). The soil is sandy-clay and has a natural low fertility. The area is characterized
by Mediterranean sub-arid climate with average maximum temperature of 33°C in August
and average minimum temperature of 3°C in January. The average rainfall is 500 mm per
year, mostly concentrated from September to April.
The Crimson Seedless vineyard was covered at veraison (first week of August) with a poly-
ethylene film, coded as “Yellow”; the film was provided by Serroplast (Rutigliano, Bari, Italy)
with a thickness of 200 µm. Only the roof of each vine row was covered with the plastic film,
while the vineyard lateral perimeter was surrounded by a plastic net.
The microclimatic variables, such as air temperature, air relative humidity and
photosynthetically active radiation (PAR), were continuously measured under the plastic film,
at 15 min frequency, and recorded during grape ripening. Sensors and data loggers were
provided by Decagon Devices Inc (Pullman, Washington, USA). The PAR sensors were situ-
ated over the canopy (2.06 m height); the sensors of air temperature and relative humidity
were situated both over the canopy (2.00 m) and under the canopy (1.70 m).
Three watering volumes, corresponding respectively to 50% (WR1), 100% (WR2) and 80%
(WR3) of daily crop evapotranspiration (ETc), were compared. Treatments were arranged in
a randomized block design with 3 replications. Irrigation was scheduled using the water bal-
ance method (Allen et al., 1998) providing the restitution of the amount of water lost by evapo
transpiration, after effective rainfall, whenever the readily available water (RAW) in the wet-
ted soil volume was depleted.
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 3/8
Daily crop evapotranspiration (ETc) was calculated by means of the Penman-Monteith meth-
od (ETo) using weather data from an automatic agrometeorological station localized near the
experimental vineyard; FAO crop coefficients defined for table grape in Mediterranean region
were adopted (Allen et al.,1998). Irrigation took place after berry set (end of May) up to one
week before harvest (II week of October). The total volumes of water supplied during the
season were respectively 1094, 2190 and 1751 m
3
ha
-1
for WR1, WR2 and WR3 treatments.
Irrigation was provided trough drip system with a single irrigation line per row and pressure-
compensated emitters, with a discharge rate of 8, 16 and 12 L h
-1
respectively for WR1, WR2
and WR3 treatments. Each row drip line had its own valve which allowed switching off the
irrigation individually for each treatment, basing on the calculated water needs.
In order to assess the vine water status and monitor the effect of the irrigation schedule,
midday stem water potential (Ψmds) was measured on 12 leaves of similar maturity per
treatment, with a pressure chamber (Soilmoisture Equipment Corp., Santa Barbara CA,
USA).
In a hot summer day of early August (after vineyard covering), the main parameters of physi-
ological leaf functioning were measured, between 09:00 and 12:00 solar time, on sun-
exposed mature main leaves of the middle shoot portion: blade temperature (Lafayette TRI-
88 infrared thermometer), stomatal conductance (CD), net photopynthesis (Pn) and leaf tran-
spiration (TR) at ~1000 µmol m
-2
s
-1
of PPF (Infrared Gas Analyzer LC pro plus, ADC,
Hoddeston, UK). Leaf water use efficiency was calculated as Pn:TR ratio. Moreover, Ψmds
was also measured the same day . All parameters were taken on 4 leaves per replicate.
At harvest, on 15 bunches per replicate, the following parameters were assessed: bunch and
berry weight, berries per cluster, berry diameters. On the berry juice, total soluble solids
(T.S.S.) by digital refractometer (Atago Co. LTD, Japan), pH, and titratable acidity expressed
as tartaric acid (T.A., neutralization with NaOH 0,1 N) were assessed and T.S.S./T.A. ratio
was calculated.
Leaf area per vine was estimated by applying the weight-to-area method; moreover, the leaf
area/grape yield ratio was calculated as an index of vegetative-reproductive efficiency. Vine
vegetative growth was also estimated by measuring cane mass at winter pruning. Crop water
productivity (CWP, fresh fruit per unit of water applied) were also computed.
Collected data were statistically processed applying ANOVA and Duncan test (p <0.05).
2.2 Radiometric laboratory tests
The radiometric tests on the plastic film were carried out at the “Laboratory for the Measure-
ment of the Radiometric Properties of Materials” of the University of Bari. Spectral direct
transmissivity of the film in the solar range was measured by a double beam UV-VIS-NIR
spectrophotometer (Lambda 950, Perkin Elmer Instruments, Norwalk, CT, USA). Measure-
ments were carried out in the wavelength band from 200 to 2500 nm in steps of 10 nm using
radiation with a direct perpendicular incidence. Spectral total transmissivity was measured by
means of an integrating sphere (diameter 60 mm) used as receiver of the Lambda 950 spec-
trophotometer, with a double beam comparative method (Wendlandt and Hecht, 1966).
Spectral diffuse transmissivity was calculated by subtracting the direct transmissivity from the
total transmissivity. The radiometric coefficients in the solar range were calculated as the
weighted average value of the spectral transmissivity using the spectral distribution of the
solar radiation at ground level as weighting function.
The spectral transmissivity in the long wave infrared radiation (LWIR) range, between 2500
and 25000 nm, were measured by a FT-IR spectrophotometer (1760 X, Perkin Elmer Instru-
ments, Norwalk, CT, USA) in steps of 4 cm
-1
. Spectral transmissivity was measured using
radiation with a direct perpendicular incidence. The transmissivity coefficients in the LWIR
range were calculated as average values of the spectral transmissivity in the wavelength
range from 7500 to 12500 nm (Vox and Schettini, 2007).
The transmissivity were performed on five rectangular samples (50x70 mm) both in the solar
and in the LWIR measurements.
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 4/8
3 Results and discussion
Figure 1 shows the spectral total and direct transmissivity of the Yellow film measured in the
solar wavelength range, between 200 and 2500 nm. The spectral transmissivity of the Yellow
film measured in the LWIR wavelength range, between 2500 and 25000 nm, is shown in Fig-
ure 2. The transmissivity coefficients of the Yellow plastic film were equal to 86.3 % in the
Solar wavelength range (300-2500 nm), equal to 86.0 % in the PAR wavelength range (400-
700 nm), equal to 90.0% in the Solar IR wavelength range (700-2500 nm), equal to 17.2% in
the UVA wavelength range (320-380 nm) and equal to 33.9% in the LWIR wavelength range
(7500-12500 nm). The Yellow film was characterised by a high total transmissivity in the PAR
wavelength range, a high solar IR transmissivity coefficient and a low LWIR transmissivity
coefficient. The Yellow film allowed to pass through the film a low fraction of UVA radiation.
The effect of the irrigation regime on the vine water status was well evident after the pea-size
stage, although at a moderate extent, as it is shown by midday stem water potential (Ψmds).
During berry growth, up to veraison, average Ψmds values were statistically different and the
lowest value was shown by WR1 treatment (-1.42 MPa), as expected. In WR2, Ψmds ranged
from -0.79 to -0.88 MPa; in WR3, it reached -1.0 MPa at veraison (Table 1). The ability of
midday stem water potential in highlighting differences in water status of table grape vines
agrees with other studies on grapevine (Choné et al., 2001; Naor and Wample, 1994;
Novello and de Palma 1997).
The effect of the irrigation regime on the leaf functioning of cv. Crimson Seedless covered to
delay grape harvest was assessed under extreme environmental conditions: the maximum
air temperature and the minimum air relative humidity of the area were 34 °C and 10%, re-
spectively, but, under the plastic film, the air temperature reached 49 °C and air humidity was
22% generating a very high air VPD, that is, 9 kPa. The Ψmds resulted -1,27 MPa either in
WR2 or WR3, and -1.363 MPa in WR1 (-8%), without any significant difference. It is known
that, with high VPD, the root uptake of available soil water is not able to match the
evapotranspirative demand and, in our experience, the differences of water status in soils
with different water supplies may be flattened.
In the present experimental conditions, stomatal conductance, net photosynthesis and leaf
transpiration had low rates (Figure 3), as expected; however, WR3 showed significant higher
values. It seemed that WR3 vines were able to maintain a higher stomatal aperture, photo-
synthetic activity and transpiration per unit of leaf area, inducing the best leaf water use effi-
ciency. The trend of leaf temperature, that, generally speaking, is negatively correlated with
transpiration, agreed with the best ecophysiologically functioning of WR3 leaves. In order to
explain why the leaf functioning was better in WR3 than in WR2 it is hypnotizable that vines
irrigated at the maximum regime had developed a larger ‘total size’ and that this habit in-
creased the total
root-to-leaf water flow hydraulic resistance which, in turn,
under extreme
environmental conditions, exerted a considerable limitation on stomatal conductance and
related parameters
.
Water availability significantly affected berry growth, inducing the lowest bunch and berry
weight in the treatment WR1 that received the lowest watering volume. Bunch weight de-
creased respectively by 24% in WR1 (severe stressed vines) and 10% in WR3 treatment
(moderately stressed vines) respect to WR1 (well-irrigated vines). Also, berry weight and
berry diameters were significantly affected by the irrigation treatments (Table 2).
As a consequence of the water deficit occurred during the crop cycle, fruit yield was signifi-
cantly affected by the different water regimes. Compared to WR2 treatment, a yield decline
of 18% and 26% was observed for WR3 and WR1 respectively, due to both a reduction in
bunch size and berry weight considering that the same clusters number per vine retained.
In this trial, the total soluble solid concentration and titratable acidity of juice were influenced
by the watering volumes (Table 3). Indeed, the lowest value of TSS was observed for the
well irrigated vines.
The application of different irrigation volumes induced significant differences in total leaf area
per vine. Leaf area of WR2 and WR3 treatments were quantitatively higher than that of the
other treatment (Table 4) and were able to support the growth and maturation of bunches, if
we accept that optimum grape evolution needs about 10 cm
2
of leaves per gram of fruit. Max-
imum berry weight was obtained in WR2 and WR3 treatments which showed a leaf area (m
2
)
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 5/8
per fresh yield (kg) ratio ranging between 1.21 to 1.39; similar results were shown also by
others authors (Kliewer and Dokoozlian, 2005).
Crop water productivity (production per unit of water applied) increased moderately from
WR2 (17.4 kg m
-3
) to WR1 (23.5 kg m
-3
) and to WR3 (17.7 kg m
-3
). Intense water stress (50%
of ETc) reduced significantly the vegetative growth as shown by the pruning weight, in com-
parison to WR1 (100% of ETc) and WR3 (80% of Etc) (Table 4).
4 CONCLUSIONS
According to the preliminary results of this study, the application of a higher irrigation volume
(WR2) on Crimson Seedless improved, at a moderate extent, the average vine water status,
and, moreover, it favored the canopy development and induced an increase in the vegetative
and productive growth. These ‘well irrigated’ vines took more advantage from the highest
water supply, in such a way that their higher metabolic activity determined a higher vegeta-
tive and productive development. Irrigation at 50% ETc (WR1) appeared to be insufficient to
achieve a complete table grape vineyard development under the environmental condition of
the Apulia region. By comparing WR1 (severe stressed vines), WR2 (well irrigated vines) and
WR3 (moderately stressed vines), the best balance among vegetative growth, grape yield,
berry quality and water use in table grape production, was obtained in WR3 vines. These
latter, moreover, in the year of trial, proved to maintain the best ecophysiological leaf func-
tioning and give the best leaf water use efficiency when extreme environmental conditions
occurred, in a hot summer period, under the plastic film used to delay the grape harvest.
In addition, from this study it is confirmed the utility of midday stem water potential as inter-
esting and simple tool for evaluation of deficit irrigation and normal irrigation on table grape
vines.
5 Acknowledgements
The work was supported by the Italian Ministry of Agriculture and Forestry Policy (Bando
OIGA D.M 2065 del 13/02/2008), Project “Razionalizzazione dell'apporto irriguo e studio eco-
fisiologico nella produzione di uve apirene in semiforzatura precoce e tardiva”; publication n°
6.
The authors shared programming and editorial work equivalently within the areas of their
expertise.
6 References
Allen, R.G., Pereira, L.S., Raes, D. & Smith, M. (1998). Crop evapotranspiration. Guidelines
for computing crop water requirements. FAO Irrigation and Drainage paper No 56.Rome,
Italy, pp 15–27.
Chonè, X., Van Leeuwen, C., Dubordieu, D. & Gaudillere, J.P. (2001). Stem water
potential is a sensitive indicator of grapevine water status. Annals of Botany, 87, 477-483.
de Palma, L., Novello, V., Tarricone, L., Lopriore, G. & Tarantino, A. (2005). Semiforzatura
precoce e tardiva del vigneto a uva da tavola. Phytomagazine, IV (13), 9-16.
Dokoozlian, N., Peacok, B., Luvisi, D. & Vasuez, S. (2000) UCE Grape Notes, May-June.
Du, T. S., Kang, S. Z., Zhang, J. H., Li, F. S. & Yan, B. Y. (2008). Water use efficiency and
fruit quality of table grape under alternate partial root-zone drip irrigation. Agricultural Water
Management, 95(6), 659-668.
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 6/8
El-Ansary, D.O., Nakayama, S., Hirano, K. & Okamoto, G. (2005). Response of Muscat of
Alexandria table grapes to post-veraison regulated deficit irrigation in Japan. Vitis, 44(1), 5–
9.
Kliewer W. M. & Dokoozlian N. K. (2005) Leaf Area/Crop Weight Ratios of Grapevines: In-
fluence on Fruit Composition and Wine Quality. American Journal of Enology and Viticulture,
56(2), 170-181.
Ezzahouani, A. & Williams, L. E. (2007). Effect of irrigation amount and preharvest irrigation
cutoff date on vine water status and productivity of Danlas grapevines. American Journal of
Enology and Viticulture, 58 (3), 330-340.
Naor, A. & Wample, R.L. (1994). Gas exchange and water relations of field-grown Concord
(Vitis labruscana Bailey) grapevines. American Journal of Enology and Viticulture. 45, 333-
337.
Novello, V & de Palma, L (1997) Genotype, rootstock and irrigation influence on water relati-
ons, photosynthesis and water use efficiency in grapevine. Acta Horticulturae, 449 (2), 467-
473.
Novello, V., de Palma, L., Tarricone, L. & Vox, G. (2000). Effect of different plastic sheet co-
verings on microclimate and berry ripening in table grape cv Matilde. Journal International
des Sciences de la Vigne et du Vin, 34(2), 49-55.
Schultz, H. R. (2000). Climate change and viticulture: a European perspective on climatolo-
gy, carbon dioxide and UV-B effects. Australian Journal of Grape and Wine Research, 6,1-
12.
Tarricone, L. &Masi, G. (2005). Influenza del portinnesto sul comportamento in vivaio della
varietà Crimson Seedless. Phytomagazine, IV (13), 41-45.
Vox, G. & Schettini, E. (2007). Evaluation of the radiometric properties of starch-based bio-
degradable films for crop protection. Polymer Testing, 26(5), 639-651.
Wendlandt, W. W. & Hecht, H. G. (1966). Reflectance spectroscopy. John Wiley and Sons,
New York, pp. 253-274.
Figure 1: Total and direct transmissivity as a function of the wavelength of the Yellow film in the solar
wavelength range (200–2500 nm).
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 7/8
Figure 2: Long wave infrared (LWIR) spectral transmissivity of the Yellow film in the wavelength range
2500-25000 nm.
Figure 3: Effect of the irrigation regime on ecophysiological leaf functioning of Crimson Seedless in a
hot summer day; from veraison, the vineyard was covered with plastic film to delay grape harvest.
Measurements were taken under plastic cover (the bar represents the standard error; different letters
indicate significant differences at P < 0,05 using Duncan test)
Table 1: Effects of the irrigation regime on midday stem water potential (Ψmds, MPa), of Crimson
Seedless at different phenological stage; from veraison, the vineyard was covered with plastic film to
delay grape harvest.
Treatment Fruit set Pea-size Berry growth Veraison Harvest
(MPa) (MPa) (MPa) (MPa) (MPa)
WR1
-1.36
a
-1.10
a
-1.42
a
-1.12
a
-1.36
a
WR2
-1.27
a
-0.99
a
-0.88
b
-0.79
b
-1.27
a
WR3
-1.26
a
-1.02
a
-1.19
b
-1.00
ab
-1.26
a
In column, means followed by different letters were significantly different at P<0.05 using
SNK test.
CD Pn TR WUE
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
(umol m
-2
s
-1
)
(mmol m
-2
s
-1
)
rate of leaf gas echange
(mol m
-2
s
-1
x 10) (umol:mmol)
b
b
a
c
a
b
a
b
ab
n.s.
WR1
WR3
WR2
0
10
20
30
40
50
°C
Leaf temperature
ab
b
a
Proceedings International Conference of Agricultural Engineering, Zurich, 06-10.07.2014 – www.eurageng.eu 8/8
Table 2: Effects of the irrigation regime on yield components of Crimson Seedless; from veraison, the
vineyard was covered with plastic film to delay grape harvest.
Treatment
Yield per vine
Bunch weight
Berry weight
Berry size (mm)
(kg) (g) (g)
lenght width
WR1 18.65
c
549
b
5.19
b
24.86
b
17.12
b
WR2 25.09
a
723
a
5.35
a
27.26
a
19.29
a
WR3 20.38
b
647
a
5.21
a
25.21
b
17.43
b
In column, means followed by different letters were significantly different at P=0.05 using SNK test.
Table 3: Effects of the irrigation regime on berry juice composition of Crimson Seedless; from
veraison, the vineyard was covered with plastic film to delay grape harvest.
Treatment T.S.S.
(°Brix)
T.A.
(g L
-1
)
pH
WR1 19.53
a
4.53
ab
3.66
a
WR2 18.23
c
4.42
b
3.62
a
WR3 19.10
b
4.65
a
3.68
a
In column, means followed by different letters were significantly different at P=0.05 using SNK test.
Table 4: Influence of the water regime on vegetative parameters and on indices of crop efficiency of
Crimson Seedless; from veraison, the vineyard was covered with plastic film to delay grape harvest.
Treatment Pruning weight
per vine
(g)
Total
leaf area per
vine (m
2
)
Crop water
productivity
(kg m
-3
)
Leaf area/
grape yield
(m
2
kg
-1
)
WR1 2750
b
20.80
b
23.50
a
1.11
b
WR2 4170
a
30.39
a
17.39
b
1.21
a
WR3 3880
a
28.45
a
17.66
b
1.39
a
In column, means followed by different letters were significantly different at P=0.05 using SNK test.