Transcript Evaluation of Drought Tolerance of Potato Cultivars Under

Evaluation of Drought
Tolerance of Potato Cultivars
Under Greenhouse Conditions
Sultan F. Alsharari and Abdullah A. Alsadon
Department of Plant Production
College of Food and Agricultural Sciences
King Saud University
P.O. Box 2460
Riyadh 11451
Saudi Arabia
Introduction
• Potato is characterized as a drought sensitive crop.
• Drought conditions resulted in reduced vegetative
growth, leaf area and plant height.
• Many studies have illustrated the effect of drought
treatments on low tuber yield in potatoes. Tuber
quality can also be affected.
Introduction
• Fresh Tuber yield was significantly correlated to root
dry mass which was reduced by drought.
• Proline content in the leaves is a key factor in
determining drought tolerant or sensitive cultivars.
• Water stress in the field or greenhouse has resulted
in an increase in proline content in potato tubers.
• From the previous studies, it is clear that drought
has a major role in decreasing potato productivity
and quality.
Objective
The objective of this study was to evaluate growth
and productivity of some potato cultivars in
response to drought treatments under greenhouse
conditions.
Materials and Methods
• Seed potatoes of seven cultivars were obtained from
local agricultural companies which commonly grow
them for fresh or processing purposes.
• These cultivars represent a selection of maturity
groups and tuber characteristics (Table 1).
Table 1: Maturity type and tuber traits of seven potato cultivars selected
in this project
Cultivars
Maturity type
Tuber Traits
Mondial
Medium-late
Oval with long oval, regular, very shallow eyes, yellow skin,
yellow flesh
Sandy
Medium
Short oval, regular, slightly inserted eyes, yellow skin, pale
yellow flesh
Hermes
Moderately early to
moderately late
Round to oval, moderately deep eyes, yellow medium rough
skin, fairly yellow flesh
Rosetta
Medium-late
Round, shallow eyes, flaky red skin, cream to light yellow
flesh
Victoria
Medium-early to
medium
Long oval, not very deep eyes, yellow skin, yellow flesh
Asterix
Moderately early to
moderately late
Long-oval, shallow to rather shallow eyes, red skin, fairly
yellow flesh
Safrane
Early to mediumearly
Long-oval, very shallow eyes, yellow smooth skin, pale
yellow flesh.
Sources:
1- Canadian Food Inspection Agency, Plant Products Directorate, Plant Health Division, Potato Section
(www.inspection.gc.ca/english/plaveg/potpom/var)
2- Nivaa Holland (www.aardappelpagina.nl/index.html)
3- Le Plant De Pomme De Terre (The French varieties) (www.plantdepommedeterre.org/eng/var.asp)
Sandy
Mondial
Rosetta
Victoria
Hermes
Asterix
Safrane
Plate 1. Tuber traits of eight potato cultivars selected in this project.
Materials and Methods
• Clonal propagation started from excised shoot
apices of growing sprouts.
• Several multiplication cycles were carried out using
single node explants. Subculture was repeated until
the required number of plantlets for each cultivar
was achieved to conduct the experiment.
• At least 200 plantlets (12-15 cm long, each with 4-5
leaves and good root system) per cultivar were
transferred to the greenhouse of the Agricultural
Research and Experiment Station at Dirab, near
Riyadh, Saudi Arabia.
Plate 2. Potato sprout which is used as starting material for clonal propagation.
Plate 3. Potato plantlet inside a test tube.
Plate 4. Potato plantlet is being cut into different stem cuttings with single node.
Plate 5. Potato plantlet is being cut into different stem cuttings with single node.
Materials and Methods
• Plantlets of 6-8cm in length and with 4-6 leaflets
were transplanted into 25 cm pots. Pots were filled
with 1 : 2 peat moss : sand
• Acclimatization was carried out by applying mist
system under plastic cover at about 10 minutes
interval for 1 minute and gradually increasing time
intervals until the end of second week when cover
was removed.
• Temperature and relative humidity were set at 24 + 2
C and 70 + 5%, respectively.
Materials and Methods
• Following two weeks of acclimatization, a class A
evapotranspiration pan was placed in a central
location between plants. Irrigation treatments were
20, 40, 60, 80 and 100% of water depletion by
evaporation (WDE). Irrigation water was added near
the plant base every other day.
• For every cultivar, eighty pots were used
(representing five irrigation treatments x 4 pots x 4
replication per treatments).
• The experiment was designed as split plot with four
replicates each. The cultivars were assigned as
main plot and irrigation treatments as sub plots.
Materials and Methods
• The first plant sample was taken at transplanting
time. Destructive harvests consisting of one plant
per subplot were randomly carried out 30, 60 and 90
days after treatment (DAT).
• Drought tolerance was evaluated based on response
of vegetative growth traits (plant height, number of
branches, leaf area) as well as tuber traits (number
and weight). Proline content in the leaves was also
evaluated.
• Data were analyzed using statistical SAS program.
Mean separation was carried out by the least
significant difference.
Results and Discussion
•
•
•
•
•
•
Plant Height
Number of Branches
Leaf Area
Proline content
Tuber number
Tuber weight
Table 1: Comparison of plant height between potato cultivars
originated from micropropagated plantlets, grown in the
greenhouse and exposed to irrigation treatments.
Average plant height (cm)
Cultivars
Days after irrigation treatment (DAT)
0
30
60
90
MON
24.66 a
73.46 b
146.77 a
158.10 a
SAN
20.66 bc
73.26 b
126.70 c
123.80 a
HER
19.33 cd
71.26 bc
123.90 c
135.00 c
ROS
23.00 ab
64.80 c
80.45 d
84.10 f
VIC
20.00 bc
84.06 a
137.99 b
151.75 b
AST
16.66 d
75.80 b
123.05 c
130.40 d
SAF
12.00
84.00 a
80.22 d
82.75 f
6.750
5.793
3.632
LSD0.05
3.283
180
160
Plant height (cm)
140
120
100%
80%
60%
40%
20%
100
80
60
40
20
0
0
30
60
90
Time in greenhouse (day)
Fig. 1: Effect of irrigation treatment on plant height of potato
cultivars originated from micropropagated plantlets and
grown in the greenhouse.
Table 2: Comparison of number of branches between potato
cultivars originated from micropropagated plantlets,
grown in the greenhouse and exposed to irrigation
treatments.
Average number of branches
Cultivars
Days after irrigation treatment (DAT)
0
30
60
90
MON
1
2.53 b
3.85 b
4.65 b
SAN
1
3.13 b
3.00 d
3.65 c
HER
1
3.00 b
3.40 c
3.55 c
ROS
1
4.26 a
4.50 a
5.35 a
VIC
1
2.46 b
2.60 e
2.70 d
AST
1
2.93 b
3.45 c
3.60 c
SAF
1
2.40 b
1.75 f
1.75 e
LSD0.05
N/S
0.775
0.212
0.284
Number of branches/plant
6
5
4
100%
80%
60%
40%
20%
3
2
1
0
0
30
60
90
Time in greenhouse (day)
Fig. 2: Effect of irrigation treatment on number of branches/plant
of potato cultivars originated from micropropagated
plantlets and grown in the greenhouse.
Table 3: Comparison of leaf area between potato cultivars
originated from micropropagated plantlets, grown in the
greenhouse and exposed to irrigation treatments.
Average leaf area (cm2)
Cultivars
Days after irrigation treatment (DAT)
0
30
60
90
MON
128.18 a
2213.10 ab
4250.80 b
2072.62 b
SAN
75.42 b
1877.60 bc
2939.30 e
1462.42 c
HER
127.90 a
2610.00 ab
5383.90 a
929.20 e
ROS
106.87 a
2669.00 a
3638.20 d
0.00 f
VIC
105.00 a
1438.10 c
3142.10e
1156.36 d
AST
73.49 b
2387.90 ab
3993.40c
2470.88 a
SAF
30.85 c
1899.20 bc
777.30f
0.75 f
LSD0.05
28.03
73.66
236.44
114.11
8000
7000
Leaf area (cm2)
6000
5000
100%
80%
60%
40%
20%
4000
3000
2000
1000
0
0
30
60
90
Time in greenhouse (day)
Fig. 3: Effect of irrigation treatment on leaf area of potato cultivars
originated from micropropagated plantlets and grown in the
greenhouse.
Table 4: Comparison of proline content between potato cultivars
originated from micropropagated plantlets, grown in the
greenhouse and exposed to irrigation treatments.
Average proline (mg/g)
Cultivars
Days after irrigation treatment (DAT)
0
30
60
90
MON
0.52
1.80 a
2.18 bc
2.81 b
SAN
0.49
1.46 ab
2.42 bc
0.57 fc
HER
0.50
1.43 ab
1.48 c
1.97 e
ROS
0.53
1.26 ab
3.66 a
4.01 a
VIC
0.47
1.50 ab
2.83 ab
2.69 c
AST
0.55
1.47 ab
2.04 bc
2.28 d
SAF
0.48
1.20 b
2.24 bc
2.90 b
0.549
0.953
0.119
LSD0.05
5
Proline content (mg/g)
4.5
4
3.5
100%
80%
3
60%
2.5
40%
2
20%
1.5
1
0.5
0
0
30
60
90
Time in greenhouse (day)
Fig. 4: Effect of irrigation treatment on proline content of potato
cultivars originated from micropropagated plantlets and
grown in the greenhouse.
Table 5: Comparison of tuber number between potato cultivars
originated from micropropagated plantlets, grown in the
greenhouse and exposed to irrigation treatments.
Average tuber number
Cultivars
Days after irrigation treatment (DAT)
0
30
60
90
MON
0
0.70 d
1.40 e
2.90 f
SAN
0
1.05 cd
9.90 b
12.70 b
HER
0
2.15 b
9.45 b
10.90 c
ROS
0
7.05 a
12.20 a
13.35 a
VIC
0
0.50 d
1.10 e
4.45 e
AST
0
1.25 bcd
2.15 d
2.65 f
SAF
0
1.75 bc
3.40 c
6.20 d
LSD0.05
N/S
0.924
0.644
0.635
18
16
Tuber number
14
12
100%
80%
60%
40%
20%
10
8
6
4
2
0
0
30
60
90
Time in greenhouse (day)
Fig. 5: Effect of irrigation treatment on tuber number of potato
cultivars originated from micropropagated plantlets and
grown in the greenhouse.
Table 6: Comparison of tuber weight between potato cultivars
originated from micropropagated plantlets, grown in the
greenhouse and exposed to irrigation treatments.
Average tuber weight (gm)
Cultivars
Days after irrigation treatment (DAT)
0
30
60
90
MON
0
1.83 cd
17.43 e
27.30 d
SAN
0
1.15 d
31.25 c
130.55 a
HER
0
2.99 cd
36.14 b
110.80 b
ROS
0
15.63 a
89.03 a
131.43 a
VIC
0
0.90 d
2.90 f
19.10 e
AST
0
3.81 bc
21.92 d
32.20 d
SAF
0
5.36 b
35.42 b
89.75 c
LSD0.05
N/S
2.278
3.092
6.169
200
180
Tuber weight (g)
160
140
100%
120
80%
100
60%
40%
80
20%
60
40
20
0
0
30
60
90
Time in greenhouse (day)
Fig. 6: Effect of irrigation treatment on tuber weight of potato
cultivars originated from micropropagated plantlets and
grown in the greenhouse.
Conclusion
• Significant differences have been reported among
cultivars and between irrigation treatments in most
traits.
• In general, as water stress increased, vegetative
growth and tuber yield decreased.
• Proline content increased as water stress increased.
Conclusion
• Significantly higher tuber weight was measured in Rosetta
plants at 60 DAT. Whereas after 90 DAT, both Rosetta and
Sandy plants had higher tuber weight followed by Hermis,
Safrina Asterix and Mondial plants, respectively.
• Accordingly three cultivars have been selected based on their
tuber weight response at the 20 % WDE. These cultivars were :
• Rosetta (drought tolerant),
• sandy ( moderately drought tolerance ) and
• Asterix ( drought sensitive ).
Acknowledgment
Authors wish to thank King Abdulaziz City for Science
and Technology for providing financial support through
Graduate Student funding program (No. GR-10-24).
Thanks are also due to Research Center of the College
of Food and Agricultural Sciences.