Presentation at the EAPR 2014 Conference

1. Relationship of WUE, yield and drought
tolerance in potato (Solanum tuberosum L.)
Evelyn Farfan, PhD
Adaptation and Abiotic Stress Genetics

2. • Introduction
• Methodology
• Results and discussion
• Conclusion
Outline:
2

3. Drought
sensitive
Shallow root
system
Low
evaporative
water
demand
High
harvest
index
Introduction:
3
©R.Zachmann

4. Introduction:
4
©SQMmodifiedbyE.Farfan

5. • 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
Neo
tbr
phu
dms
Adg
stn
AUDPC +-
Highland
tropics
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
6

7. 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)
7

8. 8
Results:
C
IP
3
9
7
0
7
7
.1
6
C
IP
3
9
8
0
9
8
.1
1
9
C
IP
3
9
8
1
8
0
.6
1
2
C
IP
3
9
8
1
9
0
.8
9
C
IP
3
9
8
1
9
2
.2
1
3
C
IP
3
9
8
1
9
2
.5
9
2
C
IP
3
9
8
2
0
1
.5
1
0
C
IP
3
9
8
2
0
3
.2
4
4
C
IP
3
9
8
2
0
3
.5
C
IP
3
9
8
2
0
8
.2
1
9
C
IP
3
9
8
2
0
8
.3
3
C
IP
3
9
8
2
0
8
.6
2
0
C
IP
3
9
8
2
0
8
.7
0
4
C
IP
3
9
2
7
9
7
.2
2
C
IP
7
2
0
0
8
8
0 .0
1 .0
2 .0
3 .0
0
5 0
1 0 0
1 5 0
Biomass(KgDW.m
2
)
TDWS
W W W D T D W S
C
IP
3
9
7
0
7
7
.1
6
C
IP
3
9
8
0
9
8
.1
1
9
C
IP
3
9
8
1
8
0
.6
1
2
C
IP
3
9
8
1
9
0
.8
9
C
IP
3
9
8
1
9
2
.2
1
3
C
IP
3
9
8
1
9
2
.5
9
2
C
IP
3
9
8
2
0
1
.5
1
0
C
IP
3
9
8
2
0
3
.2
4
4
C
IP
3
9
8
2
0
3
.5
C
IP
3
9
8
2
0
8
.2
1
9
C
IP
3
9
8
2
0
8
.3
3
C
IP
3
9
8
2
0
8
.6
2
0
C
IP
3
9
8
2
0
8
.7
0
4
C
IP
3
9
2
7
9
7
.2
2
C
IP
7
2
0
0
8
8
0 .0
0 .5
1 .0
1 .5
2 .0
Tuberyield(kg/m
2
)
W W W D
• Biomass reduction 29%
(range +5% to 44%)
• Yield reduction 39%
(range +5% to 66%)
• TDWS of CIP398208.89
104.1%, CIP398203.244
31.5%

9. 9
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

10. 10
Results:
T o ta l T ra n s p ira tio n (L )
Biomass(kgDW.m
-2
)
0 .0 2 .5 5 .0 7 .5 1 0 .0 1 2 .5 1 5 .0
0 .0
0 .5
1 .0
1 .5
2 .0
2 .5
w ell w a ter
w a te r d e fic it
w wR
2
= 0 .8 2 5 5
R
2
= 0 .8 0 5 8W D
• Total biomass and total transpiration were strongly
correlated (r=0.92, p<0.0001).

11. 11
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
W a te r U s e E ffic ie n c y (W U E )
Tuberyield(kg.m
2
)
8 9 1 0 1 1 1 2
0
2 0
4 0
6 0
8 0
R
2
= 0 .6 1 5 5

12. • 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.
12
Results:
Tolerant
Medium
Sensitive
T o le ra n c e to d e c re a s e w a te r s u p p ly (T D W S )
HarvestIndex(HI)
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
0 .0
0 .2
0 .4
0 .6
0 .8
C IP 3 9 7 0 7 7 .1 6
C IP 3 9 8 0 9 8 .1 1 9
C IP 3 9 8 1 8 0 .6 1 2
C IP 3 9 8 1 9 0 .8 9
C IP 3 9 8 1 9 2 .2 1 3
C IP 3 9 8 1 9 2 .5 9 2
C IP 3 9 8 2 0 3 .2 4 4
C IP 3 9 8 2 0 3 .5
C IP 3 9 8 2 0 8 .2 1 9
C IP 3 9 8 2 0 8 .3 3
C IP 3 9 8 2 0 8 .7 0 4
C IP 3 9 2 7 9 7 .2 2
C IP 3 9 8 2 0 1 .5 1 0
C IP 3 9 8 2 0 8 .6 2 0
C IP 7 2 0 0 8 8

13. • 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.
13
Conclusions:

14. • 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.
14
Future directions:

15. Adaptation and Abiotic
Stress Genetics Team:
Dr. Awais Khan
Dr. Evelyn Farfan
Raymundo Gutierrez
Flavio Lozano
David Saravia
Jorge Vega
Many thanks to:
15