Pome fruit heat damage to increase with climate change unless actively managed

Malcolm McCaskill, Graeme Thomson, Gavin Kearney, Ian Goodwin

Sheep : pastures OK but a welfare issue

Pastures survived heatwaves well

6oC hotter at sheep height

Unadapted stock

Ryegrass staggers

29 Jan 2009

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Hourly average, 2.3m height

Hourly maximum, 40cm height

Hourly average, 40cm height

Apples turned to mush in Goulburn Valley

Internal temperatures up to 60oC

Unsaleable fruit Harvestable fruit had shorter storage life “No future for Gala apples in Goulburn Valley” – marketing manager Montague Fresh

Which industries ?

Pre-irrig before heat3783Brassica veges

Pre-irrig before heat61149Grapes – fresh & dried

Pre-irrig before heat22155Potatoes

Heat tolerant27241Stonefruit

DPI project19283Grapes - wine

Heat-sensitive50300Pome fruit

Cold warning40869Lamb/mutton

Agonomy/breeding151498Grains

“Cool Cows” done673052Dairy

CommentsVic % of Aus

Value ($m)07/08

Industry

Cause of sunburn

High fruit temp + sunlight + UV• “Photo-oxidative sunburn” 31oC• “Sunburn browning” 41-44oC• “Sunburn necrosis” 52oCPrior heat exposure changes thresholds 1-4oCHeat shock proteins

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Temperature (C)

Tatura temperatures 2009 heatwaves

Tatura – hotter heatwaves

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1960 1970 1980 1990 2000 2010

Year

Annual maximum

(oC)

0.06oC/year

Tatura – temperature trends

ns0.003Annual minimum

ns0.006Daily minimum

***0.02Daily maximum

**0.06Annual maximum

SignificanceIncrease (oC/year)

Heatwaves are a higher priority than insufficient cold for vernalisation

Warm period during winter may disrupt vernalisation

Tatura DPI weather station, Goulburn Valley

BoM CSIRO

Data source: ARPANSA

Ultraviolet index Melbourne 2008-09

No trend in clear-sky UV since mid 1990’s

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Daily maximum

UVI

Flowering Fruit development Harvest

Gala

Pink Lady

Extreme

Evaporative cooling

Protection from high temperature but not UV20-40% more waterTemperature thresholds & design need local R&D

Clay sprays

Reflects sunlight → heat & UV protection

Removed in normal washing

Multiple applications needed

+ clay no clay

Waxes

Wax sunscreen from a Brazilian tree (canouba)EdibleMultiple applications neededProtects against UV, not high temperature

Netting

50% of new orchards now nettedReduces solar radiation, especially direct solar beamHail and bird protectionApple colour not as red

Warning systems

Conclusions

Pome fruit industry vulnerable to severe heatwaves

Scope to adapt using methods proven overseas

Trade-offs not yet researched under Aust conditions

Apples should be adaptable under climate change

Grow in tropics – no vernalisation, high UV