Managing Managing sclerotiniasclerotinia stem rot in canolastem rot in canolaCanolaCanola Research SummitResearch SummitWinnipeg, MB April 12Winnipeg, MB April 12 --13, 201113, 2011
H.R. Kutcher , F. Dokken-Bouchard, T.K. Turkington, W.G.D. Fernando, P. Bullock, D.L. McLaren, S. Boyetchko, L. Buchwaldt, D. Hegedus and I. Parkin
SclerotiniaSclerotinia stem rot strategiesstem rot strategies• Foliar fungicides are
a very important strategy for sclerotiniastem rot control
• Decision support systems– often including climatic components
• Rotation• Fertility/ Lodging• Field scouting &
record keeping • Tolerance/ resistance
SclerotiniaSclerotiniastem stem rot of rot of
canolacanola
0
10
20
30
40
50
60
Sclerotinia incidence (%) Yield (bu/ac)
UnsprayedRonilanBenlate
31% 33%
Melfort, 1998Melfort, 1998
0
5
10
15
20
25
30
35
Sclerotinia incidence (%) Yield (bu/ac)
UnsprayedRonilanBenlate
Melfort, 1999Melfort, 1999
Seeding date study, Melfort ~1999
Seeding date study, Melfort ~1999
Seeding rateSeeding rate
20
18
2120
12
14
16
18
20
22
2.8 5.1 7.3 9.5
Seeding Rate (Kg/ha)
% s
tem
rot
in
cide
nce
A98013
LSD = NS
Effect of rotation on Effect of rotation on sclerotiniasclerotinia incidence incidence
0
2
4
6
8
10
1 2 3 4 5
Years
Scl
erot
inia
inci
denc
e (%
)
Years since previous canola cropYears since previous sclerotinia-susceptible crop
From Report on 1997 Western Canada Canola Disease S urvey, R.A.A.From Report on 1997 Western Canada Canola Disease S urvey, R.A.A. Morrall et al.Morrall et al.
Effect of rotation on Effect of rotation on sclerotiniasclerotinia incidence incidence
From Report on 1997 Western Canada Canola Disease S urvey, R.A.A.From Report on 1997 Western Canada Canola Disease S urvey, R.A.A. Morrall et al.Morrall et al.
0
5
10
15
20
25
30
35
Dis
ease
Inc
iden
ce (
%)
1 2 3 4 5
Frequency of canola in rotation (yrs)
sclerotinia
blackleg
McLaren
TurkingtonKutcher
Effect of nitrogen fertilizer on Effect of nitrogen fertilizer on sclerotiniasclerotiniaincidence in western Canadaincidence in western Canada
0
5
10
15
20
25
0-20 21-40 41-60 61-80 81-100 >100
Nitrogen (lbs/acre)
Scl
erot
inia
inci
denc
e (%
)
Argentine Polish
From Report on 1997 Western Canada Canola Disease S urvey, R.A.A.From Report on 1997 Western Canada Canola Disease S urvey, R.A.A. Morrall et al.Morrall et al.
From Report on 1997 Western Canada Canola Disease S urvey, R.A.A.From Report on 1997 Western Canada Canola Disease S urvey, R.A.A. Morrall et al.Morrall et al.
Fertility rate and %Fertility rate and %sclerotiniasclerotinia stem rot stem rot
incidenceincidence
13
19
27
5
10
15
20
25
30
50% 100% 150%
Fertilizer Rate
% s
tem
rot
in
cide
nce
A98013
Sig. linear increase
ScoutingScouting• Pathogen identification:
what is out there and how will it be influenced by crop management, crop development and weather?
Pre-spray scouting (to determine benefit of fungicide)
• Past experience: what diseases occur regularly and particularly last year
Swathing time scouting (to collect information for future decisions)
Bloom staging guidesBloom staging guides
Group 2 – risk of developing resistance: medium to high Rovral Flo iprodione
Group 3 – risk of developing resistance: medium Proline 480 SC prothioconazole
Group 7 – risk of developing resistance: medium Lance boscalid
Group 11 – risk of developing resistance: high Quadris azoxystrobin
Groups 9 &12 – risk of developing resistance: medium & low - medium Astound Cyprodinil & fludioxonil
Unclassified – bio-fungicide Contans WG Coniothyrium minitans Serenade Max/ASO Bacillus subtilis
Fungicides available for Fungicides available for sclerotiniasclerotiniastem rot control in canolastem rot control in canola
Improved assessment of canola petal infestationImproved assessment of canola petal infestation
• Graduate student (M.Sc. – U of A)Drs. T.K. Turkington, S. Strelkov, H.R. Kutcher, B.D. Gossen, D.L. McLaren, F. Dokken-Bouchard, K. Rashid and V. Bisht
• Successful deployment of qPCR in private seed testing labs for commercial use
• Determine the relationship between the quantity of S. sclerotiorum DNA, agar plate petal infestation assessments, and stem rot incidence/severity
• Develop a qPCR detection method for S. sclerotiorum present on infested petals/flowers
• Correlate qPCR detection, agar plate assessementsand weather-based forecasts with final disease incidence/severity
• Develop a means of predicting sclerotinia stem rot based on weather conditions, allowing more accurate fungicide application timing
• Compare disease incidence under standard weather conditions vs. conditions of continual moisture supply (misting)
• Use standard weather conditions to accurately model sclerotinia incidence/ severity among varying crop densities through the use of a microclimate model
• MSc student, Ms Reanne PernerowskiDrs. Paul Bullock and Dilantha Fernando
Weather Based Assessment of Weather Based Assessment of SclerotiniaSclerotinia Stem Rot Risk in CanolaStem Rot Risk in Canola
• Monitor the dispersal of spores within a canola field containing various crop densities and from a neighboring wheat field
S. Boyetchko – AAFC, Saskatoon
•• 10 bacterial strains suppress:10 bacterial strains suppress:–– MycelialMycelial growth, growth, ascosporeascospore
germination/viability & germination/viability & sclerotialsclerotial formationformation
•• Broad spectrum activity Broad spectrum activity –– ((RhizoctoniaRhizoctonia solanisolani, , PhomaPhoma
lingam, lingam, AlternariaAlternaria brassicaebrassicae, , PhytophthoraPhytophthora infestansinfestans))
Incorporation of bacterial metabolites into agar
Bacterial antagonists against Bacterial antagonists against SclerotiniaSclerotinia sclerotiorumsclerotiorum on canolaon canola
Pseudomonas chlororaphis PA-23
PA-23
Phenazine
(one of the Antibiotics defused in to medium)
Sclerotinia
Sclerotinia
Dr. FernandoDr. Fernando ’’s Biological Control Programs Biological Control Program• Identification of key genes in biocontrol (mainly genes controlling
antibiotic production) from Pseudomonas chlororaphis strain PA23 against Sclerotinia.
• Novel regulatory gene identified in biocontrol from strain PA23 (patented). • In-vivo gene expression of bacterial biocontrol genes under different
environmental conditions to enhance biocontrol activity of Pseudomonas chlororaphis strain PA23.
Research to utilize sclerotinia resistance in newly identified B. napus germplasm for cultivar improvement
Lone Buchwaldt, Dwayne Hegedus and Isobel ParkinAAFC, Saskatoon Research Centre
A break through in sclerotinia resistance screening has enabled identification of new resistant germplasm, developm ent of molecular markers and identification of B. napus defense genes
1. Screening resembles natural infection of stems
2. Agar plugs with mycelium are attached to the stem with Parafilm
4. Example of a resistant and a susceptible line
3. Lesion growth is measured over three weeks
0
25
50
75
100
125A
UD
PC
0
25
50
75
100
125
% s
oft +
col
laps
ed le
sion
s
AUDPC
% soft + collapsed lesions
China E-Europe W-Europe Pakistan Japan South Korea
New B. napus lines were identified with high level of sclerotini a resistance.Figure 1 shows lines sorted from resistant to susce ptible in six geographical regions.
PAK54PAK93
PAK54 and PAK93 from Pakistan are currently being u tilized for marker development (SaskCanola - DIAP)
Zhongyou 821
Zhongyou 821 from China was the first resistant B. napus we used for development of molecular markers linked to resistance (in collabor ation with four canola breeding companies).
Additional funding is needed to exploit resistance sources from Japan and South Korea.
Figure 1.
Molecular markers (A1a - C9b) linked to nine QTLs for sclerotinia resistance were identified (Fig.2). Three QTLs contributed 30 - 40% to resistance and are suitable for marker-assisted-selection in canola breeding.
A1 A2 A3 A4 A5 A6 A7 A8 A9 A1 0
C1 C2 C3 C4 C5 C6 C7 C8 C9
0
20
40
60
80
100
120
140
6hpi 12hpi 24hpi 48hpi 72hpi
Hours after inoculation
Fol
d ex
pres
sion
BN24464
BN25790
BN15489
BN18917
BN20514
BN18865
BN26461
BN23610
BN13257
BN24404
BN20039
BN18437
BN14638
BN26419
BN23990
BN22522
BN25570
BN14979
BN26461
BN11472
BN22148
regions with complete or partial homology
A unique opportunity exists to make progress in the breeding of canola cultivars with sclerotinia resis tance. Additional funding will be used for development of molecular markers linked to resistance in lines fro m Japan and South Korea, and for identification of specific def ense genes as we are currently doing in Zhongyou 821.
Fig. 3. Defense genes up-regulated in Zhongyou 821
Defense genes up-regulated in during sclerotinia inf ection have been identified (Fig. 3). Lectinand O-methyl transferase were tentatively mapped to resistance QTLs (Fig. 2). Development of gene specific markers for O-methyl transferase and o ther genes is in progress. Selected defense genes have been cloned and B. napus transformation is in progress.
Lectins
O-methyl transferase
Lectin
Lectin
Lectin
O-mt trans
O-mt trans
Fig. 2
Results obtained with Zhongyou 821
C9a
C9b
A6a
A6b
A1a
A1b
A7a
A7b
A1c
A1d
C6a
C6b
A3a
A3b
C3a
C3b
A7c
A7d
regions with complete or partial homology
SummarySummary
• Sclerotinia stem rot of canola is extremely variable in occurrence and severity from year-to-year, region-to-region and field-to-field.
• Foliar fungicides remain the main control strategy. Tools that provide guidance to growers for fungicide application exist, and research to refine these tools continues.
• Resistant/ tolerant varieties are available and efforts continue to improve varietalresistance, in both the public and private sectors.