adaptation of sat crops to water limitation and climate change

Adaptation of SAT crops

To water limitation

And climate change

Vincent Vadez – Jana Kholova

ICRISAT

CSSA – ASA – SSSA meeting – Long Beach 2-5 Nov 2014

Today’s presentation

Basic considerations on CC / Drought

Transpiration response to VPD

Possible mechanisms

Aquaporin gene expression

Modelling effects on yield

Maximum temperature in the SAT

HypotheticTemperature

threshold

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

5

10

15

20

25

30

35

40

45

1983-HQ 1992-HQ

2001-HQ 2012-HQ

1983-ISC 1990-ISC

1998-ISC

Max

imum

T°C

Headquarter

Sahelian Center

T°C rarely crosses critical limits for SAT crops

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

1

2

3

4

5

6

7

8

Max

imum

VPD

Sahelian Center

Headquarter

Vapor pressure deficit (VPD) in the SAT

Prevalent high VPD Effect on plant water balance

VPDthreshold

21 28 35 42 49 56 63 70 77 84 91 980

1

2

3

4

5

6

7

8

9

Days after sowing

Wat

er u

sed

(kg

pl-1

)Water extraction at key times

Less water extraction at vegetative stage, more for grain filling

Zaman-Allah et al 2011See Borrell et al 2014See Vadez et al 2013

SensitiveTolerant

Trait dissectionVegetative Reprod/ Grain fill

ConductanceCanopy area

Terminal drought sensitive

Terminal drought tolerant

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.50 1.00 1.50 2.00 2.50 3.00 3.50

VPD (kPa)

H77/2 833-2PRLT-2/89-33

Tran

spir

atio

n (g

cm

-2 h

-1)

From Kholova et al 2010b

2 mechanisms of water saving: • Low Tr at low VPD• Further restriction of Tr at high VPD

Transpiration response to high VPD – Pearl millet

Transpiration response to high VPD - Peanut

Mouride

If VPD < 2.09, TR = 0.0083 (VPD) – 0.002 If VPD ≥ 2.09, TR = 0.0013 (VPD) + 0.015 R² = 0.97

B UC-CB46

TR = 0.0119 (VPD) - 0.0016 R² = 0.97

D

Transpiration response to VPD - cowpea

Tolerant lines have a breakpoint (water saving)

Tolerant Sensitive

Belko et al – 2012 (Plant Biology)

Staygreen ILs (Stg3 – Stg B) are VPD-sensitive

9 11 13 15 170.0000

0.0020

0.0040

0.0060

0.0080

0.0100

0.0120

stg1stg3stg4stgB

Time of the day (h)

Tran

spira

tion

(g

cm-2

h-1

)Recurrent R16

Stg3StgB

Transpiration response to VPD in Sorghum1 - Introgression lines

0.62 1.05 1.58 2.01 2.43 3.05 3.450.000

0.002

0.004

0.006

0.008

0.010

0.012

VPD (kPa)

Tran

spira

tion

(g p

l-1 cm

-2)

VPD-insensitive

VPD-sensitive

Transpiration response to VPD in Sorghum2 - Germplasm

2.0

3.0

4.0

5.0

6.0

7.0

152 Germplasm tested

TE

10 lowest TE are all VPD-Insensitive

10 highest TE are all VPD-sensitive

High TE lines limit transpiration at high VPD

Why are VPD-sensitive sorghum so interesting?

Vapor Pressure Deficit (VPD, in kPa)

Tran

spira

tion

rate

(g c

m-2 h

-1)

0.0 2.0 4.0

0.0

1.0

A – Insensitive to VPD – High rate at low VPD

B – Sensitive to VPD – High rate at low VPD

C – Sensitive to VPD – Low rate at low VPD

D – Insensitive to VPD – Low rate at low/high VPD

Main types of Tr response to VPD

Water use difference

Leaf conductance differences = waterVadez et al 2013 – FPB in press

4 replications

RH & T hourly recording

Weighing:7-11am = low VPD11am-15pm = high VPD

8” pots re-saturated every daysoil evaporation minimized with plastic beads

How to phenotype at large scale?

Capacity: 4,800 plotsThroughput: 2,400 plots/hour

Traits: LA, Height, Leaf angle, …

LeasyScan at ICRISAT

Leaf canopy area and conductance

Canopy Scanning

+ plant transpiration

= live water budget

Leaf canopy conductanceLoad Cells

Possible mechanisms??

???Hydraulic

Possibly located in the roots

Apoplastic Pathway

(Structural)

Symplastic Pathway

(AQP)

Water pathways in the root cylinder

Two pathways have different hydraulic conductance

Hypothesis: Aquaporin control plant water loss ?

????

Apoplastic path inhibition: H-Ferrocyanide +CuSO4Symplast path inhibition: AgNO3,

Follow-up of transpiration before/after inhibition

0

0.2

0.4

0.6

0.8

1

1.2Apoplast & symplast inhibition at low

VPD

Time

Nor

mal

ized

tra

nspi

rati

on

Apoplastic & Symplastic inhibi-

tion

Symplasticinhibition

Apoplasticinhibition

Apoplastic transport predominant

Low VPD small differences/effects

VPD-sensitive

VPD - insensitive

VPD - insensitive

0

0.2

0.4

0.6

0.8

1

1.2

Time(mins)

Nor

mal

ized

tran

spir

atio

nApoplast & symplast inhibition at high VPD

Symplasticinhibition

Apoplasticinhibition

Apoplastic transport less predominant

High VPD larger differences/effects

VPD-sensitive

VPD-insensitive

VPD-sensitive

Any difference in aquaporin expressionIn sorghum contrasting for VPD response??

0.62 1.05 1.58 2.01 2.43 3.05 3.450.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

0.016

0.018

VPD (kPa)

Tran

spir

atio

n (g

pl-1

cm

-2)

Low TE High TE Low TE High TE0

2

4

6

8

10

12

14

16

18 PIP1;1PIP1;2PIP1;3PIP1;4PIP2;1PIP2;2PIP2;4PIP2;5PIP2;6PIP2;7PIP2;8PIP2;9PIP2;10

Hig

h VP

D/L

ow V

PD

PIP relative expression (High VPD/Low VPD)

VPD – insensitive line increases expression of PIP2

PIP2;6

PIP2;9

PIP2;7

VPD-Insensitive VPD-Sensitive

grain yield gain (low TR)

-300

-200

-100

0

100

200

300

400

0 500 1000 1500 2000 2500 3000 3500

original yield (kg/ha)

yiel

d ga

in (k

g/ha

)

1 postflowering

2 flowering

3 postflowering-relieved

4 no stress

5 prefloweringOriginal yield (kg ha-1)

0

Yield increase (kg/ha) with transpiration sensitivity to high VPD: Rabi sorghum

Yiel

d in

crea

se

-1 0 +33

Crop modelling used to predict trait effects

15-30% yield increase at high latitudes

% yield increase with transpiration sensitivity to high VPD: Peanut

Lysimetric evaluation

Transpiration in pots

0.62 1.05 1.58 2.01 2.43 3.05 3.450.000

0.004

0.008

0.012

0.016

0.020

Low TEHigh TE

VPD

Tran

spira

tion

(g c

m-2

h-1

)

Low TE High TE01234567

TE

grain yield gain (low TR)

-300

-200

-100

0

100

200

300

400

0 500 1000 1500 2000 2500 3000 3500

original yield (kg/ha)

yiel

d ga

in (k

g/ha

)

1 postflowering

2 flowering

3 postflowering-relieved

4 no stress

5 preflowering

Original yield (kg ha-1)

0

AQP gene expression

Modeling of Tr restriction effect on yield

The VPD response lead to higher TE

It is itself related to differences in AQP gene expression

Major yield increase possible across crops

Breeding (donors identified)

Harness genetics – Phenotyping (new platform)

In Summary…

Thank you

Collaborators:F. Chaumont (Univ. Louvain)G. Hammer / A. Borrell / G McLean /

E van Oosterom (Univ. Queensland)B Sine / N Belko / Ndiaga Cisse (CERAAS)C Messina (Pioneer)

Donors:B&MG FoundationGCPACIARDFIDICRISAT

Technicians / Data analyst:Srikanth MalayeeRekha BadhamM AnjaiahN Pentaiah

Students:M TharanyaS SakthiT Rajini

Colleagues:KK Sharma / T Shah / F HamidouHD Upadhyaya / R Srivastava / Bhasker RajSP Deshpande / PM Gaur