Genetic control of wheat adaption to CA. Richard Trethowan

Genetic control of wheat adaptation to conservation

agriculture

Richard Trethowan, Tariq Mahmood, Zulfiqar Ali, Klaus Oldach

Implications of breeding crops adapted to conservation tillage

• New diseases (tan spot, root rots etc)

• More challenging seed bed

• Weed competition• Changes in nitrogen

management (N-use efficiency)

• Tillage x cultivar interaction

Published examinations of genotype x tillage interactions

Crop Genotypex Tillage

Literature

Wheat +/- Gutierrez (2005); Cox (1991)

Barley - Ullrich & Muir (1986)

Sorghum - Francis et al. (1985)

Maize +/- Newhouse (1985); Brakke et al (1983); Newhouse & Crosbie (1983)

Rice - Melo et al (2005)

Soybean - Elmore (1990); Pfeiffer (1987)

Pulses ? NA

Gutierrez (2005):Genotype x tillage study in wheat in Mexico

Diverse set of wheat cultivars:Berkut, Sokoll, Kambara, Weebill 1, Rebeca F20006, Romoga

F96, Nahuatl F2000, Juchi F2000, Temporalera M87, Tlaxcala F2000

Diverse environments:Irrigated & rainfed over two years

Analysis of variance; El Batan 2003 and 2004 – rainfed (Gutierrez, 2005)

Mixograph

Yield Biomass TKW P % SDS Height Mixing time

Stability

Year ** ** ** ** ** ns ns **

Tillage ** ** ns ns ** * * ns

Cultivar ** ** ** ** ** ** ** **

Cultivar x Year ** ** ** ** ** ** ** **

Cultivar x Tillage

** * ** ** ** ns ns **

Cultivar x Till x Year

ns ns ** ns * ns ns ns

Wheat grain yield for different tillage and planting

methods at El Batan (Mexico) over 2 years

0

500

1000

1500

2000

2500

ZT flat ZT beds CT flat CT beds

Yie

ld k

g/

ha

a b b b

ZT = zero tillage; CT conventional tillage

Yield of a common set of 50 genotypes under contrasting tillage regimes in Australia and Mexico

over 2 years

1000

2000

3000

4000

5000

6000

7000

Yie

ld k

g/

ha

Zero Till

CompTill

Mexico

Australia

• Higher yields under zero-till

• No significant genotype x tillage interaction in Mexico

(NS)

Source: Trethowan & Manes

Five crosses among lines with contrasting responses under zero-

tillage

Always selected under zero-tillage alternating between rainfed and irrigated conditions

Always selected under conventional tillage

alternating between rainfed and irrigated conditions

Advanced lines from both selection regimes evaluated under both zero

and conventional tillage

Sayre & Trethowan

Can a genotype x tillage interaction be designed?

Effects of Cross and Selection System on Grain Yield Averaged over 2005, 2006 and 2007

Cross x Selection System LSD (0.05) = 143 kg/ ha

5000

5200

5400

5600

5800

6000

6200

6400

SERI/..BERKUT SW94.../PBW65 FILIN./PASTOR MILAN./PASTOR PFAU../AMAD

Cross

Gra

in y

ield

(k

g/h

a)

ZERO TILL SELECTION CONV TILL SELECTION

a a a a ab b a a a

Genetic variability for improved adaptation to conservation agriculture

Trait Recent evidence

Coleoptile length Trethowan et al (2001); Rebetzke et al (2004 & 2007); Erayman et al (2006)

Coleoptile thickness Rebetzke et al (2004)

Emergence from depth Trethowan et al (2005); Joshi et al (2007)

Rapid height growth Olesen et al (2004)

Seedling vigour Liang and Richards (1999); Trethowan et al (2005); Erayman et al (2006)

Kernel weight & embryo size Liang and Richards (1999)

Faster stubble decomposition Joshi et al (2007)

Weed suppression & Allelopathy Olesen et al (2004); Bertholdsson, 2005

Early biomass/specific leaf area Liang and Richards (1999); Olesen et al (2004)

Deeper roots Reynolds and Trethowan (2007)

N-use efficiency Van Ginkel et al (2001); Trethowan et al (2005)

Disease resistance Trethowan et al (2005); Joshi et al (2007)

Seedling temperature tolerance Boubaker & Yamada (1991); Dell’Aquila and Spada (1994)

Traits important in crop emergence & establishment

T. durum A. tauschii

ABD

• Cultivars released in areas where farmers have adopted CA

• Hexaploid primary synthetics

• Landraces

• Translocations from wild relatives

• Alternative dwarfing genes

• Sources of resistance to foliar blights and root rots

D

+

AB

Useful sources of genetic variability in

wheat

Effect of different height reducing genes on coleoptile length in wheat

Rht gene GA insensitive(-) coleoptile

GA sensitive(+) coleoptile

Rht-B1b X

Rht-D1b X

Rht 7 X

Rht 8 X

Rht 9 X

Rht 12 X

Source: Rebetzke et al 2004. 2007

Genotype x tillage practice trials on two soil types at Narrabri:

Berkut/Krichauff mapping population (160 lines)

Mean yield across tillage regimes, years and soil types at Narrabri

Tillage regime

Zero till Conven till P<

Heading (days) 108.5 a 109.1 b 0.05

Yield (kg/ha) 1702 a 1368 b 0.001

Soil type Grey vertisol Red kandosol

Heading (days) 109 a 108.6 a ns

Yield (kg/ha) 1733 a 1337 b 0.001

The yield difference between zero-tillage (ZT) and conventional tillage (CT): means based on 2 sites in

2 years.

-600

-400

-200

0

200

400

600

800

0 20 40 60 80 100 120 140 160

Genotype

Yie

ld d

iffe

ren

ce k

g/h

a (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

Select diverse germplasm & screen for response to tillage measuring yield, disease and product quality to determine the extent of genotype

x tillage interactions.

Identify parents with extreme trait

expression. Include parents with

complementary QTLs

Combine in crosses with emphasis on adaptation to the

target conditions & QTLs

Implement a selection strategy. Eg combine

deep planting in a zero-tillage system with

disease inoculation & marker assisted sel.

Evaluate fixed lines across a range of

conservation agricultural practices in multi-

locational trials in the target region.

Select lines with high yield, appropriate quality and stable

performance across farmer practices within the target

region for release.

Acknowledgments:CIMMYT – Yann Manes/Ken

Sayre/Bram GovaertsSARDI – Klaus Oldach,

Hugh WallworkTeam at PBI Sydney &

NarrabriMolecular Plant Breeding

CRC