Wheat Disease Assessment Prairie Grain Development Committee Brent McCallum

Wheat Disease Assessment
Prairie Grain Development
Committee
Brent McCallum
AAFC Morden MB
Chair of the Disease Evaluation Team, Wheat Rye and Triticale Subcommittee of the PGDC
Prairie Recommending Committee for
Wheat, Rye and Triticale
Candidate Lines are Evaluated for Disease
Resistance, End Use Quality and Agronomic
Performance by;
• Disease Evaluation Team.
• Quality Evaluation Team.
• Agronomy Evaluation Team.
Evaluation Process
• Each evaluation team defines the criteria
which constitute merit for each area.
• For disease the common diseases in western
Canada are considered.
Disease Evaluation
Disease Priority
Stripe rust
Leaf Rust
Stem Rust
Common
Bunt
Fusarium
Head
Blight
1 (2017)
1
1
1
1
Leaf
Spotting
Diseases
Loose
smut
2 (formerly 2 (formerly
1)
1)
Priority 1 = Those diseases for which Coop testing is being done and the "Do-Not-ObjectTo" level of resistance is necessary for support for registration.
Priority 2 = Those diseases for which breeding and pathology research is being done in
western Canada and a minimal level of resistance is desirable to reduce economic loss to
producers.
A five point rating system of R, MR, I, MS and S is used to describe Priority 1 disease
ratings where R= Resistant, S= Susceptible, M= Moderate, and I= Intermediate.
Are We Testing the Right Diseases?
• Fusarium head blight is a major disease across
the prairies (30% of all wheat deliveries
downgraded due to FHB in 2014).
• Leaf and stem rust are common in eastern
prairies.
• Bunt and stripe rust common in the western
prairies.
• Leaf spotting diseases – are common and
important, but less emphasis is placed on these in
breeding programs (complex of causal species).
• Ergot? Testing would be difficult.
Leaf Spotting Diseases
• There are at least four different species that
cause leaf spotting diseases in wheat (Tan spot –
Pyrenophora tritici-repentis, Stagnospora blotch
Phaeosphaeria nodorum, Septoria blotch
Septoria tritici, and Spot blotch Bipolaris
sorokiniana).
• Resistance to each is likely genetically different.
• High levels of leaf spot resistance will require
resistance to each of these causal species.
The “Do-not-object” guidelines for Priority 1 diseases
wheat and triticale in Western Canada.
Disease
CWRS
CPS
GP
CWHW
CWAD
SWS
Leaf Rust
I
I
I
I
I
MS
(I 2017)
I
I
I
Stem Rust
I
I
I
I
I
MS
(I 2017)
I
I
na
Common
Bunt
I
I
I
I
I
MS
(I 2017)
I
I
I
FHB
I
I
I
I
MS
MS
MS
MS
MS
I (2017)
I (2017)
I (2017)
Stripe Rust I (2017) I (2017) I (2017)
CWRW Triticale
I (2017) I (2017)
Spelt
I (2017)
. Disease Checks and Acceptable Disease
Severity Levels for Priority 1 Diseases
Rating
R
Stem Rust
Check
Stem
Rust
Sev.
(%)
Glenn
1-10
MR
I
Columbus
20-40
MS
S
Hoffman
80100
Leaf
Rust
Check
Leaf
Rust
Sev. (%)
Stripe
Rust
Check
Stripe
Rust
Sev. (%)
Lillian
AC
Andrew
CDC
Imagine
Bunt
Bunt
Check
FHB
Index
(%)
Check
Sev. (%)
0-5
FHB37
1-25
McKenzie
1.8-4.6
10-20
5602HR
12-35
35-45
AC Cora
12-42
Neepawa
CDC
Teal*
64-100
Laura
McKenzie
10-20
Glenlea
10-40
AC Barrie
50-80
Laura
50-60
Thatcher
80-100
AC Barrie
80-100
FHB
4.0-18.6
13.725.6
18.846.4
34.558.4
Public Coop Disease Coordinators
• FHB – Maria Antonia Henriquez (Morden - AAFC) and
Anita Brule-Babel (Carman – U of M).
• Leaf Rust – Brent McCallum (Morden – AAFC).
• Stem Rust – Tom Fetch (Brandon – AAFC).
• Stripe Rust – Harpinder Randhawa (Lethbridge – AAFC).
• Common Bunt – Therese Despin (Lethbridge – AAFC).
Assigning Disease Ratings from Disease
Data
• For each disease lines are inoculated with the
races/isolates appropriate for western Canada.
• They are grown in disease nurseries (often irrigated to
promote disease) then rated for the severity of the
disease.
• These ratings are compared to the checks and the overall
average of the nursery to develop a rating scale (R,MR, I,
MS, S).
• For leaf rust the scale commonly used is 0-10%=R, 1130%=MR, 31-39%=I, 40-60%=MS, and >60%=S. This varies
by disease and year of testing, depending on the overall
severity of the nursery.
• For Rust Rating a
Modified Cobb Scale is
used described by;
• Peterson, R. F.,
Campbell, A. B. and
Hannah, A. E. 1948. A
diagrammatic scale for
estimating rust
intensity on leaves and
stems of cereals. Can J
Res 26.:496-500.
FHB Visual Index Rating
Entry
Stem
Leaf
Rust
Rust
FHB
FHB
FHB
FHB FHB
FHB
FHB
FHB
FHB
FHB
Mor
Mor Mor
Mor Mor
Car
Car
Car
Car
Car
Bunt
VRI
Sev. Rate Sev. Rate mean Rate
VRI
Rate DON
2014 PT 472
1
R
0
R
7.8
MR
63.0
S
2013 PT 472
15
MR
1
R
19.3
I
40.7
S
2012 PT472
2
r
12
MR 22.8
I
13
I
Overall PT472
R
R
I
10
MR
0
R
12.5
I
48
I
2013 PT 474
25
MR
0
R
17.5
MR
30.0
MS
2012 PT474
5
r
5
R
7.25
R
21.0
S
MR
R
I
1
R
38
I
26.3
MS
45
I
2013 PT 588
5
R
27
MR
3.3
R
15.3
I
2012 PT588
5
mr
18
MR 12.8
MR
9
MR
MR
MS
R
1
R
0
R
31.3
S
38.2
I
2013 PT 642
7
R
0
R
11
MR
12.3
MR
2012 PT642
2
r
5
R
22.5
I
16
I
R
R
S
ISD Rate
VRI
Rate
DON
ISD
Rate
39
43.7
MS
13.5
10.8
MS
53.5
MS
I
36
I
48
R
32.6
MS
9.2
8.0
I
38.8
I
8.4
I
12.5
MS
19
I
36.3 24.6
5.4
22
I
46.8
MS
63
56.8
37
MR
21
I
10.5
9
MR
5.9
16
I
37.5
I
27
39.5
26
MR
25.5
I
17.0
23.9
MR
23.0
21
MR
30
I
2014 PT 642
Overall PT 642
6.6
ISD
MS
2014 PT 588
Overall PT 588
59.1
VRI
S
2014 PT 474
Overall PT474
ISD
I
4.7
21
I
Stripe
Leaf
Stem
Common Loose
Leaf
Candidate line
2015
rust
rust
rust
bunt
Smut
FHB
Spots
Disease
Agronomy
Quality
WRT
BW496
MR
R
MR
S
MS
I
MS
Object
Support
Do not
object
Support
BW499
MR
MR
MR
I
MS
MR
MS
Support
Support
Object
Object
BW963
R
R
R
MR
I
MS
I
Do not
object
Support
Object
Support
BW965
R
MR
R
MR
S
I
I
Support
Support
Do not
object
Support
BW966
R
R
R
I
R
I
MS
Support
Support
Do not
object
Support
BW968
R
R
I
MS
MS
I
I
Do not
object
Support
Object
Object
BW971
MR
MS
R
MS
MR
I
I
Object
Support
Do not
object
Support
DT577
R
R
MR
I
MS
MS
MS
Support
Support
Do not
object
Support
DT578
MR
R
MR
R
I
MS
I
Support
Support
Support
Support
DT579
R
R
MR
R
I
MS
MS
Support
Support
Do not
object
Support
Prairie Seed Guides Use the PGDC
Ratings
Variety
Descriptions
MB Seed Guide
2016 (Draft)
Site
Years
Yield
Class/Variety
Tested bu/acre
90
64
5602HR
5603HR
41
63
5604HR CL
40
62
5605HR CL
31
62
AAC Bailey
28
50
AAC Brandon
42
65
AAC Cameron VB 20
69
AAC Connery
17
57
AAC Elie
42
64
AAC Jatharia VB
20
69
AAC Prevail VB
31
61
Loose Common Leaf
Smut
Bunt
Spots
R
MR
I
MS
I
MR
MS
I
MS
R
MR
MS
MS
MR
I
MR
S
I
S
R
I
MR
I
I
I
I
I
S
MS
I
S
S
MS
Stem
Rust
Leaf
Rust
R
MR
R
MS
R
R
MR
R
R
I
MR
R
R
R
R
R
R
MR
MR
R
R
R
Fusarium
Stripe Head
Rust
Blight
I
MS
MR
MR
S
R
MR
I
R
MR
I
I
MR
I
MR
I
MR
I
I
I
Average Disease Resistance in Bread Wheat Candidate Lines DET-WRT
5.0
Disease Rating S = 1, MS = 2, I = 3, MR = 4, R = 5
4.5
4.0
3.5
Leaf Rust
Stem Rust
3.0
Common Bunt
FHB
2.5
2.0
1.5
1.0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Prairie Seed Guides Use the PGDC
Ratings
• Each of the prairie seed guides (MB, SK and AB)
have now switched to the PGDC scale (R, MR, I,
MS, S) from the previous scale (VG, G, F, P, VP).
• Ratings can be changed if additional data is
generated post-registration. Needs to have a high
level of disease, include checks, and be
replicated.
• MCVET and AAFC collaboratively test varieties
post-registration for FHB, DON accumulation and
leaf rust.
Wheat Disease Assessment
• The system is time and labour intensive.
• Helps to ensure that candidate cultivars are
screened thoroughly for disease resistance.
• Provides reliable, multi-year, replicated data
for the Prairie seed guides.
• Pressure to reduce the years of testing, and
diseases tested, to register cultivars faster.