GRM 2013: Delivering drought tolerance to those who need it: From genetic resources to cultivar – R Trethowan

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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

0

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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