grm 2013: delivering drought tolerance to those who need it: from genetic resources to cultivar –...
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Delivering drought tolerance to those who need it; from genetic resource to cultivar
R. M. Trethowan
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Stepwise exploitation of genetic resources - do the easy things first - exploit existing gene pool genetic variation Coordinated and relevant field based phenotyping
- local, national & international levels - trait validation across the target environment
Maximised benefits from global public goods breeding - CGIAR centres and affiliates have access to diversity - CGIAR centres a mandate to “tame” diversity - National strategies to “squeeze” the most out of international germplasm
Three efficiencies to delivering drought tolerant cultivars
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Stepwise exploitation of genetic resources
Adapted cultivars Landraces Related species (crossable) Alien species
Genetics of wheat yield in the northwestern NSW
Chromosome Number of significant markers linked to yield
1A 3 1B 1 1D 4 2A 6 5A 2 5B 4 6A 12 6D 3 7A 20 7D 6
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Association analysis of a commercial wheat breeding program
Atta et al 2013
Based on 300 parents & derived progeny tested in multi-environment trials over 3 years
Better breeding strategies to improve WUE: targeting crown rot resistance in NSW
Crown rot in wheat Complex inheritance of resistance Plenty of genetic variation in the gene pool Low heritability Symptoms exacerbated under moisture stress Little progress over the past twenty years
Marker assisted recurrent selection
Combine resistance QTLs in each population Yield testing in paired plots (+/- inoculation) Off season symptom testing
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GRDC supported
Marker Assisted Recurrent Selection
Significant Markers - CSCR16/2/2-49/CUNNINGHAM//KENEDY/3/SUNCO/2*PASTOR(1RDRN#44)
Symptom expression off season (controlled conditions)
1AL, 1BL, 1DL, 2AL, 2BL, 2BS, 3AL, 3DL, 4AL, 4BL, 4DL, 4DS, 5AL, 5AS, 5BS, 5DL, 6AL, 6BL, 6DL, 7AS, 7BS
Field 1AL, 2BL, 3AL, 3B(?), 4BL, 4DL, 5BL,6BL
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T. dicoccum or durum
A. tauschii
AABBDD
DD
+
AABB
Synthetic wheat: the next step
Yield of a synthetic derivative compared to the best local check in 30 environments
0
2
4
6
8
10
0 2 4 6 8 10
Average yield of SAWYT at site (t/Ha)
Yie
ld o
f li
ne (
t/H
a)
Local CheckVorobey
Lage & Trethowan, 2008
Improving wheat WUE at Narrabri, NSW
Genotype Water use (mm) WUE kg ha-1 mm -1
D67.2/P66.270//AE.SQUARROSA (320)/3/Cunningham
273 18.0
Cunningham 261 13.9
Crusader 254 16.2
Envoy 283 12.0
Spitfire 258 14.6
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Atta et al., 2013
Improved WUE is higher grain yield
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y = 264.08x + 106.31 R² = 0.88**
3000
3500
4000
4500
5000
5500
10 12 14 16 18 20
Gra
in y
ield
(kg
ha-1
)
WUEGrain (kg ha-1 mm-1)
Envoy Cunningham
Synthetic/Cunningham
Spitfire
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Coordinated & relevant phenotyping
Phenotyping at the local level: managing heterogeneity
Walgett NSW
Managing soil heterogeniety: EM38 assessment at PBI Narrabri
1 - 25
175 - 215
Higher values indicate higher clay content, differences in texture & moisture
Indicates differences in soil texture & moisture content
Managing soil heterogeneity: EM38 assessment at Narrabri
More drought tolerant wheat: national Managed Environment Facility (GRDC supported)
Screening large numbers in the field with an accurate water balance - define year type - identify subsets - estimate trait value
Rain shelters used to: - evaluate subsets - test population tails etc
Narrabri
Yanco
Merredin
Extended impact: global network of field based managed environment facilities?
Australia (GRDC) India (GCP) China (GCP) Narrabri New Delhi Beijing
Yanco Pune Hebei
Merredin Powarkheda Shanxi
Ludhiana Xinjiang
Genotype x tillage practice trials on two soil types at Narrabri: evaluation of a mapping population
Keeping screening relevant: selection for adaptation to moisture conserving farming practices
The yield difference between zero-tillage and conventional tillage: 2 sites x 2 years.
-600
-400
-200
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200
400
600
800
0 20 40 60 80 100 120 140 160
Genotype
Yie
ld d
iffer
ence
kg/
ha (Z
T-C
T) Krichauff
Berkut
Significant QTL effects for yield under contrasting tillage regimes on two soil types in 2 years
Chr Interval Treatment Soil type Additive effect %
Allele
1B gwm268/wPt-3475 CT Grey v 8 K
1B wPt-1313/gmw140 CT Grey v 10 K
1D cdf19/wmc216 CT Red k 10 K
2D wPt-3728/cfd44 ZT Grey v 9 K
2D gmw484/wmc27 ZT Red k 9 B
5A cfa2155/wPt1370 ZT Grey v 25 B
5A cfa2115/wPt1370 CT Grey v 14 B
5A cfa2115/wPt1370 CT Red k 9 B
5B wmc99/wPt2373 ZT Grey v 12 B
Trethowan et al. 2012.
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Maximise the benefits of global public goods research
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The CGIAR has: Multiple crop focus Access to genetic diversity Resources to introduce this diversity into adapted materials The network to distribute materials globally
Global distribution of CIMMYT International Wheat Nurseries, 1994-2004
ESWYT HRWYT SAWYT IAT
(Elite Spring Wheat Yield Trial (ESWYT), High Rainfall Wheat Yield Trial (HRWYT) and Semi-Arid Wheat Yield Trial (SAWYT)) and the International Adaptation Trial, 2001-2004
Matthews et al. 2008
Probe genotypes for soil borne constraints (International Adaptation Trial)
Probe genotypes are: Genetically similar (either near-isogenic or same background) Similar yield in the absence of the stress Differentiate in the presence of the stress
Thirty seven different probe genotype comparisons in the IAT including soil borne diseases and abiotic constraints:
Matthews et al., 2011 GRDC supported
30o S
30o S
0o 0o
30o N
30o N
60o N
60o N
International Adaptation Trial locations 2001-2007
100 locations; 32 countries 165 trials trial mean yield range 0.42 – 9.13 t/ha
Root Lesion Nematode_Isoline (Pratylencas thorneii)
NA
No Difference
Significant negative
Significant positive
Genotypes Gatcher GS50A > Gatcher
30o S
30o S
0o 0o
30o N
30o N
60o N
60o N
The average genetic correlation of IATs at Roseworthy (2001-2004), with global IATs
Matthews et al. 2011
CIMMYT Australia ICARDA Germplasm Evaluation (CAIGE)
Improved access to (and exploitation of) CIMMYT and ICARDA
germplasm by Australian wheat breeders Co-ordinated germplasm introduction, quarantine, evaluation &
data management Two-way flow of information between Australia and the CGIAR
centres (CAIGE website)
Supported by the GRDC
Locations where CAIGE yield trials are grown
CAIGE Yield Trial approx 200 entries 4 organisations 9 locations
In addition, materials are screened for resistance to: Rust Septoria Tan spot Crown rot
Site groupings based on germplasm performance
Site grouping 1. Narrabri, North Star, Wongan
Hills 2. Toodyay, Junee 3. Roseworthy, Horsham 4. Esperance, Merredin
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1.Overall the SAWYT tends to have the
highest yield potential and ICARDA materials the lowest.
2.The SAWYT best in Group 1 environments – Narrabri, NorthStar and Wongan Hills – while the ESWYT most suited to Group 2 environments – Junee and Toodyay.
3.ICARDA nurseries best adapted in southern and western areas (i.e. Group 3 and 4 environments)
4. Lines with high yield potential could be identified from both CIMMYT & ICARDA nurseries in all regions
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Grain yield of CAIGE gemplasm in Australia
Acknowledgements
Funding: GRDC, ACIAR, Generation Challenge Program & the Wheat
Research Foundation Collaboration: Australia’s wheat breeding groups & companies CIMMYT, ICARDA, ICAR (India) & CAAS (China)
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