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Optimal flowering periods (Manangatang MRU) - Bonnie Flohr (CSIRO)

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Why optimal flowering periods?
• Autumn rainfall decline (Cai et al. 2012)
• At least partly attributable to anthropogenic climate change (Cai et al. 2013) and results in the systems which bring the ‘autumn break’ to SE Australia being less frequent (Pook et al. 2006, 2009)
• Sowing dates required for current cultivars to achieve optimal flowering periods coincide with marked rainfall decline which has regionally reduced yield
• In addition, > farm size and > extreme spring weather
• Farmers need new cultivar x management strategies to stabilise flowering time

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Optimal flowering periods (Manangatang MRU) - Bonnie Flohr (CSIRO)

  1. 1. Optimal flowering periods Bonnie Flohr| Mallee Sustainable Farming updates, Manangatang 17 February 2016 AGRICULTURE
  2. 2. Acknowledgements  CSIRO Agriculture • James Hunt, John Kirkegaard, Brad Rheinheimer, Tony Swan ANU • John Evans Funding • GRDC and ANU 2 | Optimal flowering periods|  Bonnie Flohr
  3. 3. Why optimal flowering periods? • Autumn rainfall decline (Cai et al. 2012) • At least partly attributable to anthropogenic climate change (Cai et al.  2013) and results in the systems which bring the ‘autumn break’ to SE  Australia being less frequent (Pook et al. 2006, 2009) • Sowing dates required for current cultivars to achieve optimal flowering  periods coincide with marked rainfall decline which has regionally  reduced yield • In addition, > farm size and > extreme spring weather • Farmers need new cultivar x management strategies to stabilise  flowering time 3 | Optimal flowering periods|  Bonnie Flohr
  4. 4. Wheat’s optimal flowering period (OFP) 4 | • Water stress • Heat stress • Frost • Disease • Inadequate  growth OFP • Critical for yield • A compromise of all  factors • Highest yields come  with ~5‐10% frost  damage Optimal flowering periods|  Bonnie Flohr
  5. 5. • Previously optimal flowering periods have been defined by last  spring frost and first heat event  • Impact of seasonal water supply on optimal flowering period has  been overlooked • Using APSIM to model yield combines historic weather records  (including water availability), biomass accumulation and  temperature to identify optimal flowering period = novel  approach Things to consider in optimal flowering periods 5 | Optimal flowering periods|  Bonnie Flohr
  6. 6. Method • Key inputs for model – Year duration (1963‐2013) – MET file for site (SILO) – Soil file for site  – Management: TOS (April 1‐ July 15) – Fertiliser – Irrigation – Variety (mid‐fast) 6 | Optimal flowering periods|  Bonnie Flohr
  7. 7. 7 | APSIM sites‐ SE Australian wheat belt Optimal flowering periods|  Bonnie Flohr
  8. 8. 8 | Optimal flowering  period =19 August  to 13 September Optimal flowering periods: Manangatang Optimal flowering periods|  Bonnie Flohr Optimal flowering  period (95% of  achievable yield) +ve standard deviation  (variation) ‐ve standard deviation  (variation) 15 day rolling mean
  9. 9. Optimal flowering period 9 | 9 ‐29 September Lameroo Optimal flowering periods|  Bonnie Flohr Waikerie 23‐ 29 August
  10. 10. 10 | OFP is independent of cultivar maturity type Mid‐ fast spring Winter very slow spring Optimal flowering periods|  Bonnie Flohr
  11. 11. A trade off… drought, frost and heat 11 | Flowering date Yield (kg/ha) Mean peak APSIM 9-Aug 2456 Mean peak frost and heat reduced 25-Aug 1819 Frost and heat index interception 8-Sep N/A Waikerie Optimal flowering periods|  Bonnie Flohr
  12. 12. OFP and declining rainfall: Lameroo 12 | 1998‐2013 vs. 1963‐1997 Optimal flowering periods|  Bonnie Flohr 25 Aug‐ 8 Sept 4 Sept ‐ 19 Sept
  13. 13. • 1. Sowing date Ways to hit the optimal flowering period 13 | Reference: NVT, Victorian Winter Crop Summary 2015 Optimal flowering periods|  Bonnie Flohr APSIM sowing date range for peak average yield (OFP)‐ mid‐fast maturity wheat Location April May Waikerie > x < Lameroo > x x < Manangatang > x < = problematic is large sowing programs
  14. 14. Ways to hit the flowering window • 2. Genetics x Management  14 | Early sowing with slow developing cultivars will  not be adopted in the majority of the Australian  wheat belt (WA, SA, Vic) until there is a winter  wheat that is as high yielding as current elite fast  developing spring wheat cultivars e.g. Mace,  Corack  Optimal flowering periods|  Bonnie Flohr
  15. 15. SA, WA & NW Vic need a fast maturing winter  wheat 15 | Mace Vrn‐A1 Vrn‐B1 Vrn‐D1 v a v Krichauff Vrn‐A1 Vrn‐B1 Vrn‐D1 b v v Peake Vrn‐A1 Vrn‐B1 Vrn‐D1 a v v X Or Fast winter wheat Vrn‐A1 Vrn‐B1 Vrn‐D1 v v v 25% of F2 progeny Optimal flowering periods|  Bonnie Flohr
  16. 16. Fast winter wheat: RAC2341 • RAC2341‐ AGT Roseworthy breeding program – vav x avv • 70% Mace  • Responds to vernalisation  – Requires cold temperature accumulation to initiate flowering, fast‐spring  wheats have a low requirement   • Fast to develop once vernalised  • 4 x experimental sites in GRDC early sowing project‐ James Hunt 16 | Optimal flowering periods|  Bonnie Flohr
  17. 17. Flowering time vs. yield ‐ Minnipa 22‐August – 8 September Optimal flowering periods|  Bonnie Flohr
  18. 18. Minnipa SA results 2015‐ James Hunt 18 | Yield (t/ha) Time of sowing Cultivar 13‐Apr‐15 29‐Apr‐15 13‐May‐15 Wedgetail 2.8 2.5 1.9 Eaglehawk 2.9 2.3 1.8 RAC2341 3.4 3.6 2.7 Cutlass 3.5 3.6 2.9 Trojan 3.3 3.9 3.0 Mace 2.9 3.8 3.2 Very slow spring 2.2 1.7 0.9 Mid winter 2.4 2.0 1.7 Fast winter 2.7 2.6 2.0 Fast spring 2.0 3.0 2.5 P‐value <0.001 LSD (p=0.05) 0.3 Optimal flowering periods|  Bonnie Flohr
  19. 19. 19 | RAC2341 sown 13 April @ Minnipa SA (photo taken 1 Sep 2015‐ James Hunt) Flowered 26 July 2.9 t/ha Flowered 3 September 3.4 t/ha Optimal flowering periods|  Bonnie Flohr
  20. 20. Temora results 2015 20 | Grain yield (t/ha) Time of sowing Cultivar 17‐Apr 27‐Apr 7‐May 15‐May Wedgetail 4.3 4.1 3.7 3.2 RAC2341 5.5 4.9 4.4 4.3 Gregory 4.7 4.8 3.9 3.8 Condo 4.7 5.8 4.9 4.4 P‐value <0.001 LSD (p=0.05) 0.4 Optimal flowering periods|  Bonnie Flohr
  21. 21. Temora 2015 21 | RAC2341 (fast winter), a broad sowing window (17 April‐ 15 May) same flowering date Optimal flowering periods|  Bonnie Flohr Optimal flowering  period
  22. 22. Key points • Consider spring drought (seasonal water supply) as an important  determinate of the optimal flowering period, along side frost and  heat • There is less flexibility in time of sowing with fast maturing wheats  to achieve the optimal flowering period than thought, timely  sowing cultivars to your environment is key to achieving optimal  flowering periods and yield • Varieties that can respond to the environment (e.g. RAC2341) can  hit the optimal flowering period across multiple sowing dates  (=flowering date stability), increasing yield and system flexibility in  a variable climate 22 | Optimal flowering periods|  Bonnie Flohr

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