Drought stress in potato plants

Pankaj Banik

M.Sc. Student

Supervisor: Prof. Karen Tanino

Potato (Solanum tuberosum L.)

• Herbaceous C3 plant, tetraploid, 48 Chromosomes

• 3rd most important food crop grown in 150 countries

Source: USDA National

Nutrient Database

Drought in potato plants

• Stolon formation & tuberization

– Most sensitive stage

• Longer period in tuber formation

• Decrease in tuber number, growth

& yield

Sensitive

Even a short period

Tuber production & quality

Rationale

• Lots of work in molecular biology

• Little work

–Whole plant physiology

• History

• Acclimation

• Stress & Recovery

–Western Canada

–Short growing season

Long-term goal

To determine the key elements of

potato drought stress resistance

Experiment setup

Applying drought stress

NA

Stress & Recovery

Survival score

• 0 – vigorous growth

• 1 – Green, 25% leaves

wilted

• 2 – Green, 50% leaves

wilted

• 3 – 75% leaves wilted,

stem bent, lower leaves

changed color

• 4 – All leaves wilted,

some dead, weak stem

• 5 – Plant died

Severe stress (scale 3)

After recovery (scale 0)

Measurements

• Leaf WC

• Stomatal aperture

• Leaf water loss over 15 minutes

• Leaf temperature

• Leaflet water content

• Flowering time

• Stem diameter and plant height

• Biomass

• Trichome Number

• Leaf cuticle layer

• Yield

Applying drought stress

1 1

1 1

2 2

2 2

3 3

3 3

4

4

4

4 5 5

6

6

7

8

9

Contrasting Genotypes

AAFC Potato breeding program, Lethbridge

– Fv12246-6

– V1002-2

– Russet Burbank (RB)

Hypotheses

• Drought stress history of genotypes affects

subsequent drought stress resistance

• Drought acclimation and recovery are key

components of resistance

• Stomatal aperture parameters are associated

with yield under drought stress conditions

Experiment I (V1002)

Generation 1 Generation 2 Generation 3

NA (Non Acclimated)

NA-NA NA-NA-NA

NA-DAS (Drought Acclimated & Stressed)

NA-NA-DAS

NA-NAS (Non Acclimated & Stressed)

NA-NA-NAS

DA (Drought Acclimated)

DA-NA DA-DA-NA

DA-DAS DA-DA-DAS

DA-NAS DA-DA-NAS

Yield (Stress history)

0

10

20

30

40

50

60

70

80

90

NA-NA NA-DAS NA-NAS DA-NA DA-DAS DA-NAS

Treatments

Me

an

of

Yie

ld

CB

D

A B C D

A

0 2 4 6 8 10 12 14 16

NA-NA

NA-DAS

NA-NAS

DA-NA

DA-DAS

DA-NAS

Trea

tmen

ts

Tuber No.

<5g

5-20g

20-50g

50-100g

>100g

Leaf water loss over 15 min

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Time (min)

% w

ate

r lo

ss

NA-NA-NA

NA-NA-DAS

NA-DAS-NA

NA-DAS-DAS

DA-DAS-NA

DA-DAS-DAS

2

*

1 2

1

LWC at maximum stress

74

76

78

80

82

84

86

88

NA-NA-NA NA-NA-DAS NA-NA-NAS NA-DAS-NA NA-DAS-DAS NA-DAS-NAS DA-DAS-NA DA-DAS-DAS DA-DAS-NAS

Treatments

% le

af

wa

ter

co

nte

nt

A

A

Experiment II

Genotypes Treatments Codes

Fv12

Non Acclimated (NA) Fv-NA

DAS (Drought Acclimated & Stressed) Fv-DAS

NAS (Non Acclimated & Stressed) Fv-NAS

V1002

NA V-NA

DAS V-DAS

NAS V-NAS

RB

NA RB-NA

DAS RB-DAS

NAS RB-NAS

Treatments Genotypes

Leaf water content

Acclimation

Maximum stress

NA > DAS ***

NA > DAS > NAS *

V > RB > Fv *

V > RB > Fv ***

Leaf water loss over 15 minutes

Acclimation

Recovery

Overall ***

Overall ***, NA > NAS ***

V > Fv ***, V > RB ***

Overall ***, V > RB ***

Leaf Temperature during

Stress

Recovery

NAS>NA***, NAS>DAS*, Overall: *,

NA>DAS*

RB > V *, RB > Fv *

Overall:*, RB~V*

Leaflet water content during

recovery

DAS > NAS * RB > V ***, RB > Fv *, Fv > V *

Leaf Trichome No. Genotype – Treatments interaction: ***

Shoot dry biomass Overall: ***, Fv > V ***, Fv > RB ***

Plant height Oveall: ***, RB > Fv ***, RB > V ***

Stem diameter Overall: ***, Fv > V ***, RB > V ***

Stem Number Overall: ***, Fv > V ***, RB > V ***

***p<0.05, *p close to 0.05

Leaf Cuticle layer

NA-NA-NA

(no stress history)

DA-DAS-DAS

(Stressed over 3

generations)

Ongoing & future work

WUE

• Carbon isotope

discrimination

Stomatal aperture

& density Stem water potential (Non

destructive, real time

LICOR-6400

Acknowledgements

• Prof. Karen Tanino

• Dr. Helen Tai, Sustainable Agriculture Environment System (SAGES)

• Prasanto Mondol

• Prof. Sakti Jana

• Eldon Siemens

• Jackie Bantle

Thank you