Do dormancy breakers have a role in fruit production?

Transcription

1 Do dormancy breakers have a role in fruit production? APAL Speed updating 25 June 2015 Sally Bound Perennial Horticulture Centre Tasmanian Institute of Agriculture

2 Background Gradual seasonal transitions Inadequate winter chill in some areas Future impact of climate change Resulting in: poor and/or non-synchronous bud-break extended flowering period TASMANIAN INSTITUTE OF AGRICULTURE 2

3 So what is the problem with non-synchronous bud-break and extended flowering? wide range of different growth stages on tree unpredictable responses to thinning chemicals lack of uniformity of fruit maturity (multiple picks) Impact on orchard profitability TASMANIAN INSTITUTE OF AGRICULTURE 3

4 Can we solve the problem? Chemical manipulation to terminate dormancy 1. reduce the chilling requirement 2. modulate the timing of budbreak, flowering and fruit maturity 3. increase the number of buds breaking dormancy of strong apically dominant species, subsequently increasing flowering and yield Chemicals used as rest breakers dinitro-ortho-cresol (DNOC) thidiazuron (TDZ) Armobreak (alkolated amine) thiourea [SC(NH 2 ) 2 ] gibberellic acid (GA 3 ) Dormex (hydrogen cyanamide) various oils & surfactants potassium nitrate (KNO 3 ) Waiken (fatty acid esters) Australian studies Chemicals: Sites: Cultivars: Dormex, Waiken, Armobreak Tasmania - Grove, Cradoc Victoria - Officer, Shepparton Fuji, Imperial Gala, Granny Smith, Pink Lady, Sundowner TASMANIAN INSTITUTE OF AGRICULTURE 4

5 Results - Dormex TASMANIAN INSTITUTE OF AGRICULTURE 5

6 Results - Dormex TASMANIAN INSTITUTE OF AGRICULTURE 6

7 Results - Waiken TASMANIAN INSTITUTE OF AGRICULTURE 7

8 Results - Waiken & Armobreak 4% Waiken Armobreak (2% Armothin + 4% KNO 3 ) Both applied 28 Aug Waiken & Armobreak compressed flowering period from 33 to 16 days TASMANIAN INSTITUTE OF AGRICULTURE 8

9 Results - impact with thinning program 4% Waiken at 6 wbfb 1.0% ATS at 20% & 80% bloom TASMANIAN INSTITUTE OF AGRICULTURE 9

10 Key findings Dormex effective but toxic chemical must be applied while trees dormant, otherwise phytotoxic effect Waiken can apply later in season, up to greentip recommended around 6 weeks before anticipated FB Questions arising comparison between Dormex and Waiken clarify impact on thinning program effect on fruit maturity Where to from here? TASMANIAN INSTITUTE OF AGRICULTURE 10

11 AP12029 (project variation) Understanding apple & pear production systems in a changing climate Project Leader: Dr Heidi Parkes (DAF, Qld) Team: Dr Heidi Parkes, Dr Osi Tabing (DAF, Qld) Susie Murphy-White, John Sutton (DAFWA) Dr Sally Bound, Steve Paterson (TIA, Tas) Trial details: 3 locations (Qld, WA, Tas) 1 cultivar (Gala) 2 chemicals: Dormex & Waiken TASMANIAN INSTITUTE OF AGRICULTURE 11

12 AP12029 (project variation) Objectives to determine: 1. The efficacy of Waiken and Dormex for inducing earlier flowering and concentrating the flowering period in Gala under Australian conditions? 2. If the use of these dormancy-breaking sprays is cost effective: - does a more concentrated flowering period result in the need for fewer sprays for Western Flower Thrips and dimpling bug? - is the efficiency of blossom thinning likely to be improved? 3. Whether Waiken and Dormex are equally effective? 4. The impact of these chemicals on fruit set, yield, variability of maturity at harvest, length of harvest? TASMANIAN INSTITUTE OF AGRICULTURE 12

13 Acknowledgements Paul Miller (Paul Miller & Associates, Victoria) & Les Mitchell (Agrisearch Services, Shepparton) for conduct of the Victorian trials SST Australia Pty Ltd for supply of Waiken and provision of funding for the initial Victorian trials HRDC (now HIA) for provision of funding for the Dormex studies under project AP94043, and the later Waiken studies under project AP98011 HIA for providing funds for the project variation for project AP12029 TASMANIAN INSTITUTE OF AGRICULTURE 13