Relationship of WUE, yield and drought tolerance in potato (Solanum tuberosum L.)

Evelyn Farfan, PhD Adaptation and Abiotic Stress Genetics

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• Introduction• Methodology• Results and discussion• Conclusion

Outline:

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Drought sensitive

Shallow root system

Low evaporative

water demand

High harvest index

Introduction:

© R

. Zac

hman

n

4

Introduction:

© S

QM

mod

ified

by

E.Fa

rfan

• 2 commercial varieties (UNICA y Achirana-INTA) and 13 potato genotypes from CIP’s advanced breeding population.

• Growing period: 90 days

Methodology:

acl

Tbr

blb

spr

Neotbr

phu

dms

Adg

stn

AUDPC +-

Highlandtropics

Late Blight Resistant (B3)

Population

Lowland tropics

Virus Resistant(LTVR)

Population

chc

bth

6

Methodology:

• Greenhouse: 28/15°C day/night, 48/89% min/max relative humidity

• Treatments: Well-watered (WW) Water deficit (WD)

• Design: Slit plot N=5

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Methodology:

• Traits: Water use efficiency (WUE) Transpiration Relative water content (RWC) Osmotic potential (OP) Biomass (total and per organ) Leaf area index (LAI) Chlorophyll content (SPAD units) Tolerance decrease to water supply

(TDWS)

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Results:

CIP3970

77.16

CIP3980

98.11

9

CIP3981

80.61

2

CIP3981

90.89

CIP3981

92.21

3

CIP3981

92.59

2

CIP3982

01.51

0

CIP3982

03.24

4

CIP3982

03.5

CIP3982

08.21

9

CIP3982

08.33

CIP3982

08.62

0

CIP3982

08.70

4

CIP3927

97.22

CIP7200

880.0

1.0

2.0

3.0

0

50

100

150

Biom

ass

(KgD

W.m

2 )

TDW

S

WW WD TDWS

CIP3970

77.16

CIP3980

98.11

9

CIP3981

80.61

2

CIP3981

90.89

CIP3981

92.21

3

CIP3981

92.59

2

CIP3982

01.51

0

CIP3982

03.24

4

CIP3982

03.5

CIP3982

08.21

9

CIP3982

08.33

CIP3982

08.62

0

CIP3982

08.70

4

CIP3927

97.22

CIP7200

88

0.0

0.5

1.0

1.5

2.0

Tube

r yie

ld (k

g/m

2 )

W W WD

• Biomass reduction 29% (range +5% to 44%)

• Yield reduction 39% (range +5% to 66%)

• TDWS of CIP398208.89 104.1%, CIP398203.244 31.5%

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Results:

• WUE of total biomass was higher in WD than in WW

• Water was mainly used in tuber production rather than above ground biomass in tolerant genotypes

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Results:

Total Transpiration (L)

Biom

ass

(kgD

W.m

-2)

0.0 2.5 5.0 7.5 10.0 12.5 15.00.0

0.5

1.0

1.5

2.0

2.5well waterwater deficit

wwR2 = 0.8255

R2 = 0.8058WD

• Total biomass and total transpiration were strongly correlated (r=0.92, p<0.0001).

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Results:

• WUE was also correlated with both yield and total biomass (r = 0.78, p<0.001; r= 0.55, p<0.05)

• A crop may support yield, but not biomass

Water Use Efficiency (WUE)

Tube

r yie

ld (k

g.m

2 )

8 9 10 11 120

20

40

60

80

R2 = 0.6155

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• Three clear groups can be distinguished from this analysis (tolerant, medium, sensitive).

• CIP397077.16, UNICA, CIP398208.620, and Achirana-INTA were the four genotypes ranked as tolerant while CIP398203.244 was rated as sensitive.

Results:

Tolerant

Medium

Sensitive

Tolerance to decrease water supply (TDWS)

Harv

est I

ndex

(HI)

0 20 40 60 80 100 1200.0

0.2

0.4

0.6

0.8

CIP397077.16

CIP398098.119

CIP398180.612

CIP398190.89

CIP398192.213CIP398192.592

CIP398203.244

CIP398203.5

CIP398208.219

CIP398208.33

CIP398208.704

CIP392797.22

CIP398201.510

CIP398208.620CIP720088

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• Selection for higher WUE and drought tolerant genotypes does not always compromise total biomass and yield under well-limited conditions.

• Five genotypes with high TDWS and HI were identified out of the fifteen evaluated.

Conclusions:

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• Wide range of potato germoplasm in field conditions (improved and native).

• Effect of drought stress at different developmental stages.

• Evaluation of root system architecture and its relation with drought tolerance.

Future directions:

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Adaptation and Abiotic Stress Genetics Team:

Dr. Awais KhanDr. Evelyn FarfanRaymundo GutierrezFlavio LozanoDavid SaraviaJorge Vega

Many thanks to: