Potential yields and wheat 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
Source
(1976)
Journal of the
Australian
Institute
of Agricultural
Science 42,
139–148.

Irrigated Wheat Yield changes in the Yaqui Valley
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 1982–2012
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
• 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)
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)
• 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
0.5%
Yield gap
45% of FY

Wheat Yield progress in the United Kingdom
(humid, winter wheat)
• 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%
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
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)

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

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.

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 managerial) , but it is also the path to more sustainable wheat
systems and more efficient use of inputs (water, nutrients, energy) per
kg grain produced
• Gap closing is generally considered to involve activities to promote
adoption of existing technologies, i.e. agricultural extension, but this
can be facilitated by breeding and agronomic research

• Breeding can help gap closing through:
‒ More robust varieties e.g. more suited to soil disorders and new conservation
agriculture systems and
‒ Especially better pest/disease resistance, and here genetic engineering will help.
• Agronomic research can also help gap closing, for example:
‒ More appropriate conservation agriculture techniques/machinery
‒ Easier ways to diagnose and avoid nutrient deficiencies and
‒ to reap the benefits of greater rotational diversity in wheat cropping
systems.
• No wish to underrate the importance and complexity of
extension, which has also been subject to extensive research,
debate and ongoing reinvention (e.g. innovation platforms).
• But time doesn’t permit further discussion of extension except to
say that, however it is structured, it remains vital and
unfortunately resource intensive, and much neglected in
developing countries.

• Also unfortunately, beyond R, D and E, other barriers to yield gap closing are especially evident in
developing countries:
‒ Farmer skill levels, farmer access to financial resources and strong land tenure, weak farmer empowerment
‒ Poor input supplies, infrastructure, markets, and the absence of the institutions
• Eliminating these barriers has a long way to go as we look at wheat across the world:
‒ Low level of R, D and E investment generally in developing countries (R & D intensity < 1%)
‒ Urban and elitist biases in national policies which continue the neglect of rural development
‒ Inefficient seed systems, and
‒ the on-going shrinkage of farm size in developing countries which only impedes modernization and perpetuates
rural poverty.
• Norman Borlaug understood well the big picture in agricultural development, and right from his
early days here in the Yaqui Valley, strove at all levels of government to eliminate these barriers by
promoting small farmer friendly policies
• Overall however at least for wheat the days of rapid yield gap closing have past, and keeping up the
average global rate of yield gap closing of say 0.4% will be difficult

Summary of wheat farm yield prospects globally
• Potential yield (new tools cancelled by diminishing
biological returns) +0.6% , no change
• less Yield gap change ( note diminishing
exploitable yield gap in W Europe, elsewhere) ‒(‒ 0.4%), at best
• plus Carbon dioxide rise (2ppm p.a. ) but cancelled by warming zero
• and likely gradual shift from irrigated to rainfed production yield negative?
---------------------
Net prospect for FY 1.0%, at best
Likely rate of change
(linear %p.a. relative to 2010 FY)

Summary (continued)
• Most estimates suggest 1% p.a. yield growth is not enough to meet
demand growth esp. in next 20 years
• Consequences: equilibrium modelling points to likely higher real wheat
price relative to 2010, greater stress for poor wheat consumers, larger
wheat area (more rainfed), greater trade in wheat.
• Result responsive to more R , D and E investment but elasticity
uncertain and maybe low (<0.2); also effectiveness of R D & E an issue,
and other rural investments (e.g. roads, education) often necessary
• With attention to all of these, the world might scrape by on wheat, but
prospect for more urban price-driven crises remains higher with wheat
than with other staples

CSIRO Plant Industry
Tony Fischer | Honorary Fellow
t +61 2 6246 5244
e tony.fischer@csiro.au
w www.csiro.au
Thank you
for your attention, and I acknowledge
all the researchers whose published
data has helped put together this
presentation.
Also if you want to know more,
there are 70 pages in the Wheat
chapter in our new book (Fischer,
Byerlee and Edmeades 2014) and
over 500 in the whole book! Come
and visit the poster.

Wheat Yield changes in the Yaqui Valley
• Especially early in the
Green Revolution, one
important aspect of this
technological progress
was the positive variety x
fertility (N) interaction,
looking like this:
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
0 75 150 225 300
Grainyield(t/ha)
Nitrogen fertilizer rate (kgN/ha)
1980s varieties
1950s varieties
1950s N level
1980s N level
Effect of :
:
variety
X N
variety
N
Source
Ortiz-
Monasterio et
al (1997)

Wheat Yield changes in the Yaqui Valley
• Secondly, part of the early FY
progress by Borlaug in the Yaqui
valley came from new varieties with
better stem and leaf rust resistance
• This is not PY progress, which must
be measured without disease;
however maintaining disease
resistance is a major achievement
(and on-going role) of wheat
breeding
• Also in measuring PY progress in
vintage trials, must be careful to
avoid disease, which if present will
tend to bias upwards the estimated
rate of PY progress, as the following
research here at CENEB showed:
Source
Sayre et al
(1998)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
1965 1975 1985 1995
Grainyield(t/ha)
Year of Variety Release
With fungicide
No fungicide
(=leaf rust)
slope 27 kg/ha/yr*** or 0.5%
slope 92 kg/ha/yr*** or 1.7%

CSIRO.
Yaqui Valley: now > 90% of wheat on raised beds.

Wheat yield progress in Kansas
( dry, winter wheat)
• Acreage loss to
GM maize and
soybean
• Conservation
tillage has led to
less summer
fallows
• Tough
environment
including many
biotic stresses
Source
Nalley et al (2008),
NASS (2012)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
1980 1985 1990 1995 2000 2005 2010
Grainyield(t/ha)
Year
PYw
FY
slope 20 kg/ha/yr*
0.7%
0.4%
Yield
Gap
36% of FY

0.0
0.5
1.0
1.5
2.0
2.5
1850 1870 1890 1910 1930 1950 1970 1990 2010
GrainYield(t/ha)Change in average farm yield (FY) of rainfed wheat in Australia
over the period 1852−2012 showing major drivers of change (curves
hand fitted)
Source
Adapted from
Donald
(1964),
Fischer (2009)
and J.F.Angus
and
J.Kirkegaard
pers. comm.
2011
Exploitative
farming
Fallowing, P fertilizer,
adapted vars.
Mechanization, legume
pastures, herbicides
Semidwarf vars., break
crops, N fertilizer
Millennium
drought

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

Farm yield (FY) wheat in WANA
Country
Average 2010-2012
Increase 1993-2012
%p.a., rel. 2010-12
Comments
Prodn
Mt
Area
Mha
Yield
t/ha
Prodn Area Yield
Turkey 20.52 7.91 2.60 (0.3) -1.3 1.3 FY takeoff 2009?
Iran 13.21 6.80 1.94 1.5 (0.2) 1.3
Syria 3.52 1.57 2.24 (-0.1) (0.0) (-0.2)
Iraq 2.65 1.34 1.98 3.1 (-1.5) 3.8
S. Arabia 1.21 0.20 5.93 (-3.4) -7.5 1.7
Kazakhstan 14.07 13.10 1.06 2.8 1.1 2.0
Uzbekistan 6.59 1.40 4.71 4.6 1.4 4.2
Afghanistan 4.32 2.37 1.82 3.3 1.2 2.6
Morocco 4.92 3.03 1.63 2.3 0.8 (2.1) FY slope P=0.103
Algeria 2.86 1.79 2.69 3.1 (1.1) 2.7
Tunisia 1.32 0.65 2.00 (1.6) (-0.9) 2.2
Egypt 8.13 1.30 6.23 2.4 1.7 1.0 FY plateau >2003
Ethiopia 3.07 1.54 1.99 4.3 3.4 2.1
Sudan 0.34 0.20 1.71 (0.4) (-1.6) (1.6)
Source FAOSTAT Mar 2014

Wheat yield progress in India and
in Punjab State 1992-2012 (irrigated low latitude)
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
0.7%
FY Punjab State
FY India
1.0%
Yield gap
56%
of FY
• India yield not
stagnant
• Punjab progress
not unlike Yaqui
Valley but all
yields lower
• Yield gap larger
than Yaqui
Valley: many
constraints
Source
FAOSTAT, Singh et al 2011,
I. Sharma pers.comm.

Summary of case studies on Wheat Yield Progress
Wheat
mega-
environment
Region
Estimated farm or potential yield (t/ha)
and yield gap (%)
Rate of change
(% p.a.)d
FY PY Yield gap FYe PYe Yield gapf
Spring wheat regions
1 Yaqui Valley, Mexico 6.4 9.0 41 g0.9 0.3 −0.6
1 Punjab, India 4.5 7.0 56 g0.7 0.4 −0.3
1 Jiangsu, China 4.6 7.5 63 0.8 0.7 −0.1
4 Western Australiab 1.8 2.6 44 g1.0 0.5 −0.5
6 Saskatchewan,b Canada 2.3 3.8 69 0.8 0.6 −0.2
6 Saskatchewan,b,c Canada 2.2 3.6 64 0.7 0.5 −0.2
6 North Dakota,b USA 2.5 4.0 60 1.0 0.7 −0.3
6 Finland 3.7 4.8 30 1.0 0.8 −0.2
Winter wheat regions
10 Shandong and Henan, CN 5.8 8.8 52 1.7 0.7 −1.0
11 United Kingdom 8.0 10.7 34 0.4 0.6 +0.2
11 Northern France 8.6 10.8 26 0.3 1.1 +0.8
12 Kansas,b USA 2.8 3.8 36 0.7 0.4 −0.3
Overall average
Average (n = 12) 4.43 hna 48 0.83 0.61 −0.23
bRainfed cropping regions commonly experiencing water shortage so PYw was estimated
cDurum wheat dAll rates of FY progress and gap closing contains the direct effect of CO2 rise (~0.2% p.a.)
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
gFY rates of change include small but significant weather trends (see text) forwhich no correction is applied here; two were unfavourableand one favourablefor FY
Source: Fischer et al (2014)

Wheat
Mega-environment
Weighting factor
(fraction of total)
Estimated values for
2008–10
Estimated rate of change relative
to 2008–10 values
(% p.a.)
Area
Producti
on
PY
(t/ha)
Gap
(%)
FY
(t/ha)
PY Gap FY
Spring wheat regions
1,2,3 = irrig., humid, low lat. 0.23 0.23 5.5 83 3.0 0.6 −0.4 1.0
4,5 = dry and hot, low lat 0.17 0.08 2.5 67 1.5 0.3 −0.9 1.2
6 = High lat. 0.20 0.13 3.0 50 2.0 1.0 −0.2 1.2
Winter (and facultative) wheat regions
10 = irrigated, middle lat 0.06 0.09 6.5 44 4.5 0.5 −1.1 1.6
11 = humid middle lat. 0.23 0.38 6.5 30 5.0 0.7 0.0 0.7
12 = dry, middle lat. 0.11 0.09 3.0 30 2.3 0.5 −0.3 0.8
After weightedaverage
World average 1.00 1.00 a4.5 b50 a3.0 b0.6 b−0.4 b1.0
Key wheat yield statistics by world wheat megaenvironments.
aWeighted by area of WME bWeighted by production of WME
Source:.
Source: Fischer et al (2014). Estimates apply
to 2008–10 when average world wheat area
was 222 Mha and production was 674 Mt

Presentation title | Presenter name32 |

Potential yields and wheat progress

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Andere mochten auch

Andere mochten auch (20)

Ähnlich wie Potential yields and wheat progress

Ähnlich wie Potential yields and wheat progress (20)

Mehr von CIMMYT

Mehr von CIMMYT (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Potential yields and wheat progress