Overhanging foliage appeared to

lessen sunburn in all treatments;

fruit from control and netted vines

had the greatest leaf cover and the

lowest degree of sunburn. On the

Granite Belt site ambient light

measurements at véraison showed

leaf-plucked treatments had highest

exposure, data for the vertical plane

showing low light penetration in

most treatments with healthy

canopy, except the sprawl which

had little overhead cover. Over the

season the overhanging foliage was

progressively lost. Measurement of

bunch zone UV radiation in the

Shiraz indicated highest UV

exposure in the high plucked

treatments as well as slight

increases in sunscreen treatments;

while protecting the berries,

overspray on leaves may reflect

more UV radiation onto the fruit.

Queensland wine industry development has relied upon adoption

of viticultural practices from established winegrowing regions.

Such procedures are not necessarily best practice under

Queensland conditions. The wine grape growing regions of

Queensland are climatically distinct from other Australian

regions with relatively wet growing seasons, at times with severe

peak heat loads. Queensland also hosts the most northerly and

some of the highest altitude vineyards in Australia, with higher

ultra violet radiation exposure than any other Australian grape

growing region. Furthermore, fruit exposure may be exacerbated

by regional management practices used to minimise risk of

fungal infection. The Queensland wine industry has identified

fruit exposure management as a critical issue to be addressed.

An extension project was undertaken to demonstrate effects on

fruit exposure of alternative canopy management practices for

Chardonnay and Shiraz in vineyards in Queensland‟s Granite

Belt, South Burnett and Scenic Rim. Growers inspected the sites

in their regions prior to harvest, and fruit from the Granite Belt

site was harvested, chemically analysed and processed into wine

for sensory assessment. The wines were evaluated by judges at

the 2010 RASQ Wine Show and sensory profiles determined.

Findings were discussed with the Queensland wine industry and

wines made available for sensory assessment by participants in

the Queensland Viticulture Seminar in June 2010.

Fruit exposure was modified by fruit zone leaf removal from the

most easterly (low - L) or both sides of the canopy (high - H); at

pea size (P) or at véraison (V); a 50% shoot removal (ST);

throwover bird net (Net); application of commercial „sunscreen‟

products (calcium carbonate or kaolin clay); a non manipulated

VSP „control‟ (C); and „sprawl‟ for Shiraz. The Granite Belt

vineyard used for the demonstration was, unfortunately, subject

to hail and frost events in late 2009, resulting in some damage to

vines. This combined with late season water stress and disease

pressures to impact on the results of this trial.

All treatments fell within recommendations for leaf area / fruit

weight. Fruit analyses showed similar harvest yields and

profiles of TSS, pH, TA. Marginal differences were seen in

Chardonnay phenolic profiles and Shiraz anthocyanins, tannins

and phenolics, and while slight differences were seen, the

wines had similar sensory profiles.

METHODS

Differences were noted in exposure and sunburn of the Chardonnay grapes prior to harvest, although only marginal differences were seen in

the measures of fruit and wine quality of either variety. We are wary of making inferences from this study over a difficult season where site and

seasonal factors overwhelmed differences due to imposed management practices. Inconsistent additional fruit exposure occurred via

defoliation relating to early season frost and hailstorms and late season water stress followed by fungal disease pressure. We plan to follow up

with demonstration trials in vineyard sites with lower risk of unfavourable events.

Influence of Bunch Exposure in a Commercial Queensland

Vineyard on Chardonnay and Shiraz Fruit and Wine Quality

U. J. Kennedy1, T. Hassall2, M. Deegenaars1, D. J. Rhymer3 and R. P. Learmonth1

1CSBi, University of Southern Queensland, 2Queensland Primary Industries &

Fisheries, 3Ballandean Estate Wines, Queensland, Australia.

INTRODUCTION RESULTS AND DISCUSSION

CONCLUSIONS

This work utilised the facilities of the Queensland College of Wine Tourism, and was supported by the Queensland wine industry and the

GWRDC RITA grant RT08/03-1 “Addressing fruit exposure and sunburn in Queensland wine grape vineyards”. We would also like to thank

Sirromet, Clovely and Ironbark Ridge for provision of vineyard demonstration sites, the RASQ Wine Show judging panel, and Kim Larsen

(USQ) and USQ Wine Technology students for assistance with picking and processing grapes and juice and monitoring ferments.

ACKNOWLEDGEMENTS

At pre-harvest vineyard walks, it was noted that the worst

sunburn was seen in fruit with little canopy or leaf cover (leaf

removal or shoot thinned). Little difference in severity of sunburn

was seen between pea size and véraison leaf removal. In the

South Burnett and Granite Belt sites, the severity of sunburn was

equal or greater on fruit situated on the more easterly side of the

canopy, anecdotal evidence suggesting this may be due to

afternoon cloud cover typical in the region. Tasting fruit

indicated better acid and flavour balance on unexposed fruit,

with more exposed and sunburnt fruit showing overripe and

„cooked‟ fruit flavours and lack of acidity.

TreatmentContr

olLV LP

HV

HP S

TNet

CaC

O3

Kao

lin c

lay

Spra

wl

% U

V l

igh

t in

bu

nch

zo

ne

0

5

10

15

20

25

30% UV irradiation Shiraz

TreatmentContr

olLV LP

HV

HP S

TNet

CaC

O3

Kao

lin c

lay

Spra

wl

% v

isib

le l

igh

tin

bu

nc

h z

on

e (

ve

rtic

al

pla

ne

)

0

1

2

3

4

5

6 Shiraz

Chardonnay

TreatmentContr

olLV LP

HV

HP S

TNet

CaC

O3

Kao

lin c

lay

Ab

so

rban

ce

0

1

2

3

4

5Total phenolics

Total hydroxycinnamates

Total flavonoids

Estimate of brown pigments

TreatmentContr

olLV LP

HV

HP S

TNet

CaC

O3

Kao

lin c

lay

Spra

wl

mg

/ g

or

a.u

. /

g0.0

0.5

1.0

1.5

6.0

7.0

8.0Tannins (mg / g)

Anthocyanins (mg / g)

Phenolics (a.u. / g)

0

1

2

3

4

5

6

7

Clarity

Hue

Intensity

Herbaceous aroma

Berry aroma

Dark fruit aroma

"Overripe" aroma

Palate lengthAcidity

Bitterness

Astringency

Alcohol heat

Herbaceous palate

Berry fruit palate

Dark fruit palate

Control

Heavy pluck pea size

Heavy pluck veraison

Light pluck pea size

Light pluck veraison

CaCO3

Kaolin clay

Shoot thinned

Net

Sprawl

Colour

Palate

Aroma

Shiraz

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Clarity

Colour

Herbaceous aroma

Tropical aroma

Citrus aroma

"Overripe" aroma

Palate length

Acidity

Bitterness

Astringency

Alcohol heat

Herbaceous palate

Tropical palate

Citrus palate

Control

Heavy pluck pea size

Heavy pluck veraison

Light pluck pea size

Light pluck veraison

CaCO3

Kaolin clay

Shoot thin

Net

Aroma

Palate

Colour

Chardonnay