Causes and Prevention of Thompson Seedless Berry Collapse

Transcription

1 Causes and Prevention of Thompson Seedless Berry Collapse Davinder Singh, Michael Treeby, Kristen, Pitt and Peter Clingeleffer 7 th International Table Grape Symposium, November 2014 CSIRO AGRICULTURE

2 Berry collapse: other varieties Sultana Crimson Seedless

3 Fluorescein diacetate (FDA) staining & microscopic symptoms of berry collapse (2009) Thompson seedless Healthy berry Crimson seedless Berries can have loss of tissue without collapse, but collapsed berries always have loss of tissue. Black America Berry collapse starts with loss of tissue, but the primary trigger is unknown.

4 Thompson Seedless berry collapse Devastating problem in 3 of the last 15 seasons 1997/ / /08 (losses in the order of $100m) This presentation: symptoms contributing factors minimisation treatments? grower best practice (2008)

5 Thompson Seedless berry collapse: symptoms Apparent around veraison Smaller soft berries with high sugar content (increased water loss) Markings/discolouration Brown striations Distal end collapse

6 Thompson Seedless berry collapse: symptoms Healthy Striated Striated with collapse started Collapsed

7 Thompson Seedless surface features Normal Collapsed Top Cracks in wax and cutin Bottom

8 Berry collapse: microscopic symptoms Healthy berry Collapsed berry Berries can have loss of tissue without collapse, but collapsed berries always have loss of tissue. Berry collapse starts with loss of tissue.

9 Brown striations as an indicator Healthy berry Berry with berry collapse symptoms Berry with brown striations Cell death Two out of three berries with brown striations showed cell death/loss of cells in the berries A large proportion of berries with brown striations will collapse

10 Berry moisture loss under controlled conditions (40 o C) Treatment Berry wt. (g) Sugar ( 0 Brix) 12 hour moist. loss (g) 12 hour % moist. loss 1. Healthy Striated Striated with collapse started Collapsed Moisture loss from berries in oven at 40 0 C 1. Healthy 2. Striated 3.Striated with collapse started 4. Collapsed

11 Maximum daily temperatures: Nov. Feb Av.1997/98 and 2000/01 Av. 1998/99, 1999/2000 and 2001/ o C Days from November 1

12 Early field studies low incidence years Plot # Nutrient Carbon- cincturing increases incidences of berry collapse Mineral- no significant relationship between low mineral levels and berry collapse Spatial variability Soil fertility- C, N and ph vs berry collapse (no relationship) Soil water availability? % bunches Treatment with collapse Cincturing Control 13 Cincture 24* Calcium Control 20 Early 21 Late 13 Early & late Row # % bunches with berry collapse

13 GA & high temperatures interaction Use of GA critical factor Promotes cell division and mitochondrial activity Increased demand for energy, nutrients and water Trials established in glasshouses to study interaction between GA and heat Berry size Heat/water GA Days after flowering

14 Glasshouse studies Thompson seedless - GA & heat interactions Bunches dipped in GA set ~1 week apart (Inflorescences chosen for the trial were flowering roughly at the same time) Heat treatment: 19 November until 09 December, daily average temperature of 24.7 C (with min. and max. temperatures of 14.4 C and 42.7 C) 11 daily average temperature of 33.1 C (with min. and max. temperatures of 14.4 C and 56.0 C)

15 Glasshouse: Heat & GA induce berry collapse No GA GA No GA GA Moderate heat Severe heat GA treated + Severe heat GA treated berries prone to heat related damage - sun damage, berry collapse, brown striations, soft berries Water stress further exacerbates the berry collapse incidences in GA treated bunches Trigger point between 35 o C and 40 o C

16 Glasshouse vs Field- Microscopic symptoms Field Glasshouse Berry collapse in glasshouse and field has same microscopic symptoms

17 Field studies: Rootstock and irrigation interactions (2009) Berries per bunch Rootstock Irrigation Sun damage Whole soft berries Brown striations Berry diameter (mm) Berry wt. (g) Sugar ( Brix) Control Ramsey Double Stressed Control Schwarzmann Double Stressed Schwarzmann more susceptible than Ramsey Water stress increased the number of soft and striated berries Extra water had little impact (low incidence)

18 Field studies: Rootstock, irrigation and cincture interactions (2009) Rootstock Irrigation Cincture Sun damage % Whole soft berries % Soft tips % Brown striations % Total Control Ramsey Control Stressed Stressed Control Schwarzmann Control Stressed Stressed Cincturing significantly increased berry damage

19 Management issues: Best practice based on 2008 experiences Large differences in incidence of symptoms between properties Adjacent properties Best practice to minimise incidence Rootstock selection Cover crops reduce temperature? Big trellises to reduce temperature and increase humidity Early irrigation to fill soil profile (buffering capacity) Management of drip irrigation (35-55 L per day water transpired, December) Covers positioned away from the canopy Evaporative (cooling misters)

20 Treatments to minimise berry collapse in Thompson Seedless Diverse range of products have been trialled, largely without success:- Nutrients (Calcium) Plant health hormones known to be involved in plant defence mechanisms (jasmonic acid and salicylic acid) Plant health enhancers (Brotomax) Anti-transpirants GA alternative (putrescine) Particle Film Technology which reduces canopy and fruit temperature shows considerable promise (eg. Surround )

21 Surround lowered the leaf surface temperature Surround is used as a protectant to reduce sunburn, heat and stress in wine grapes, apples, nashi, citrus etc 50kg/1000 litres at the time of flowering and two subsequent sprays pre veraison at 5kg/1000litres Wine grapes Apple Surround lowered the leaf temperature by 2-3 C in Ramsey and Schwarzmann

22 Field studies: Rootstock, irrigation and Surround interactions Berries per bunch Rootstock Irrigation Surround Sun damage Whole soft berries Brown striations Berry diameter (mm) Berry wt. (g) Sugar ( Brix) Control Control Ramsey Stressed Stressed Control Schwarzmann Control Stressed Stressed Surround reduces stress damage, promotes early maturation and increases berry size

23 Summary:Thompson Seedless berry collapse symptoms described contributing factors prime factors GA Temperature (>35 o C) exacerbating factors water stress cincturing rootstock minimisation treatment (PFT) grower best practice water management temperature reduction avoid use of GA and cincturing if hot Long term future for Thompson Seedless? Risk of more hot seasons Limited water supply

24 Thank you Acknowledgements: Tori Nguyen: Technical Officer, CSIRO Joel Beloy: Technical Assistant, CSIRO Participating growers CSIRO AGRICULTURE