Potential yields and yield gaps in wheat: the bases of wheat yield progress

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Presentation delivered by Dr. Tony Fischer (CSIRO, Australia) at Borlaug Summit on Wheat for Food Security. March 25 - 28, 2014, Ciudad Obregon, Mexico. http://www.borlaug100.org

Transcript of Potential yields and yield gaps in wheat: the bases of wheat yield progress

  • Potential yields and yield gaps in wheat: the bases of wheat yield progress CSIRO PLANT INDUSTRY Tony Fischer | Honorary Fellow, CSIRO Plant Industry, Canberra, Australia Presentation at Borlaug Summit on Wheat for Food Security 25-27 March 2014, Ciudad Obregon, Mexico Methodology for understanding past yield progress Some case studies Global summary by cases and megaenvironments Wheat yield prospects
  • World average wheat yield 1983-2012 known here as farm yield (FY) Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer2 | 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 1980 1990 2000 2010 2020 2030 Yield(t/ha) ? Source FAOSTAT 2014 Slope linear at 32 kg/ha/yr (not curvilinear nor exponential) Predicted yield in 2012 is 3.1 t/ha Slope relative to 2012 yield is 1.0% per annum Must disaggregate
  • Wheat Breeding in Mexico and Yield Increases Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer3 | Source (1976) Journal of the Australian Institute of Agricultural Science 42, 139148.
  • Irrigated Wheat Yield changes in the Yaqui Valley Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer4 | Source SARH, SAGARPA, Fischer and Wall (1976), Bell et al (1995), Ahrens et al (2012); D.Flores pers. comm. 0 100 200 300 400 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 1950 1960 1970 1980 1990 2000 2010 NFert.rate(kg/ha) GrainYield(t/ha) Potentialyield(PY), CIANO plots against year of release,1970s best agronomy N rate on farm Average Farm Yield (FY) slope 266 kg/ha/yr 6.0% of 1975 FY
  • Yield change in Yaqui Valley 19822012 Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer5 | Source SARH, SAGARPA; D.Flores, K.D. Sayre and I Ortiz- Monasterio pers. comm. 0 100 200 300 400 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 1975 1980 1985 1990 1995 2000 2005 2010 2015 Nfert.Rate(kgN/ha) Yield(t/ha) slope 60 9 kg/ha/yr 0.9% of2012 FY FY vs year N Rate FY 2012 6.4 t/ha slope 28 10 kg/ha/yr 0.3% of2012 PY PY vs year of release PY 2012 9 t/ha Yield Gap 41% of FY Surveys and satellite imagery suggest currently no lack of N, but small constraints: late planting late watering summer weeds
  • Summary of approach In essence the approach views FY as PY less Yield Gap : FY = PY Yield Gap with the yield gap unlikely to be < ~30% of FY (or FY unlikely to be > ~77% of PY); larger gaps have an exploitable component Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer6 | Also, FY progress is PY progress less Yield Gap change: rel. change in FY = rel. change in PY less rel. change in gap Note Gap and gap change determined by difference (gap = PY FY) Relative progress in PY is measured against year of release under latestagronomy, and this is assumed to translate into the same relative progress in FY upon full adoption of the technologiesmeasured in PY progress. As such PY progress contains any positive agronomy by variety interaction. PY progress measure must avoid bias from greater disease in older varieties and must have representative natural resource base.
  • Division of world wheat lands into wheat megaenvironments (WMEs) for balanced sampling WME Moisture Latitude Global wheat Area (%) Examples Spring wheat 1 Irrigated Low 17 Mexico, S Asia, Egypt 2 + 3 High rainfall Low 5 Wet N Africa, Brazil 4 Low-mod rain Low 15 Australia, wet N Africa 5 Irrigated Low, hot 2 Bangladesh, Sudan 6 Low-mod rain High 20 Canada, Siberia Winter (including facultative) wheat 10 Irrigated Middle 6 North China Plain 11 High rainfall Middle 23 Eurasia, E USA 12 Low mod rain Middle 11 Great Plains, Anatolia Total 100 Potential yields and yield gaps in wheat | Tony Fischer7 |
  • Wheat yield progress in India and in Punjab State 1992-2012 (irrigated low latitude) Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer8 | 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 1990 1995 2000 2005 2010 2015 Grainyield(t/ha) slope 24 kg/ha/yr* 0.4% PY Punjab State slope 30 kg/ha/yr*** 0.7% FY Punjab State Yield gap 56% of FY Punjab progress not unlike Yaqui Valley but all yields lower Yield gap larger than Yaqui Valley: many small constraints Source FAOSTAT, Singh et al 2011, I. Sharma pers.comm.
  • Wheat Yield Progress in Western Australia (water limited hence PYw) Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer9 | Notable gap closing due to better agronomy: - conservation tillage and herbicides = earlier sowing , more moisture - more crop diversity - more nitrogen Gap partly driven by risk aversion of farmers in dry rainfed areas Source NVT, ABARES 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 1980 1985 1990 1995 2000 2005 2010 2015 GrainYield(t/ha) FY slope 18 kg/ha/yr** 1.0% PYw slope 14 kg/ha/yr*** 0.5% Yield gap 45% of FY
  • Wheat Yield progress in the United Kingdom (humid, winter wheat) Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer10 | Excellent PY data from HGCA Results confirmed McKay et al (2010) applying linear mixed model analysis to the data, showing that agronomic progress in PY appears exhausted. Also yield gap small and increasing More so in France where FY not increasing significantly despite PY breeding progress Source HGCA, FAOSTAT slope 34 kg/ha/yr** 0.4% slope 64 kg/ha/yr*** 0.6% 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 1990 1995 2000 2005 2010 GrainYield(t/ha) FY PY Yield Gap 34% of FY Note yield axis offset.
  • Summary of case studies on Wheat Yield Progress Potential yields and yield gaps in wheat: the bases of wheat yield progress | Tony Fischer11 | Region (Wheat MegaEnvironment) Estimated farm or potential yield (t/ha) and yield gap (%) in 2010 Rate of change (% p.a.)d FY PY Yield gap FYe PYe Yield gapf Spring wheat regions (some examples) Yaqui Valley, Mexico (WME1) 6.4 9.0 41 g0.9 0.3 0.6 Punjab, India (WME1) 4.5 7.0 56 g0.7 0.4 0.3 Western Australiab (WME4) 1.8 2.6 44 g1.0 0.5 0.5 North Dakota, b USA (WME6) 2.5 4.0 60 1.0 0.7 0.3 bRainfed cropping regions commonly experiencing water shortage so PYw was estimated eAll FY and PY slopes are statistically significant at P < 0.10 or better, except for the FY slope for northern France (P = 0.13) fCalculated as FY rate of change less PY rate of change Source: Fischer et al (2014) Winter wheat regions (some examples) Shandong and Henan (WME10) 5.8 8.8 52 1.7 0.7 1.0 United Kingdom (WME11) 8.0 10.7 34 0.4 0.6 +0.2 Kansas,b USA (WME12) 2.8 3.8 36 0.7 0.4 0.3 Average all cases (n = 12) 4.43 hna 48 4 0.83 0.61 0.06 0.23 After weighting for WME production (WME 1 =23%, WME 6 = 13%, WME 11 = 38%) World 3.0 4.5 50 1.0 0.6 0.4
  • Wheat yield prospects (next 20 - 40 years): continued PY progress? 1 Currently at about 0.6% p.a. comparatively low (cf. rice 0.8%, maize 1.1%, soybean 0.7%) but no sign of a PY limit being approached although progress becoming more difficult and more expensive New agronomy is part of PY progress but options for greater yield are limited, possibilities: Soil physical status (e.g. Controlled Traffic) Soil microbiology in general Water limited situations: plastic mulching better seasonal climate forecasts and weather insurance for intermediate latitudes, earlier sowing, possibly with head frost resistance (new agronomy for greater resource use efficiency is however vital) Potential yields and yield gaps in wheat | Tony Fischer12 |
  • Wheat yield prospects: continued PY progress? 2 But conventional breeding still makes steady yield progress , and new tools are continuing to be developed to help efficiency which is undoubtedly falling: Computing, biometry, mechanization, robotics = more yield trials Managed environments, remote sensing, targeting physiological traits Molecular markers, culminating in genomic selection (GS) And untapped wheat genetic resources remain a likely source of yield genes but difficult and hence expensive to access by prebreeders Potential yields and yield gaps in wheat | Tony Fischer13 |
  • Wheat yield prospects: continued PY progress? 3 What about non-conventional breeding? Heterosis, becoming so important now in tropical rice, will likely be harnessed for a 10-15% yield jump, possibly helped by GM The private sector can and will likely play a greater role in wheat breeding Can genetic engineering (GM) help on potential yield? Direct impact on PY/PYw unlikely in 20 years at least, indirect via freeing breeding resources more likely. And can we improve on 0.6% PY progress? Even with the private sector becoming involved? Overall looks quite difficult to me. Potential yields and yield gaps in wheat | Tony Fischer14 |
  • Wheat yield prospects: closing the yield gaps? 1. Gaps are smaller in wheat (avg 50%) than in rice (e.g. avg 76%, often >100%) and especially maize (36% in USA, but 100% in China, Argentina and >200% in SSAfrica) Gap closing inevitably means intensification on all fronts (physical inputs and man