Transcript Presentation

Yield Loss Prediction Tool for Asian Soybean
Rust:
A Multi-Disciplinary Project
S. Kumudini, J. Board, C. Godoy, C. Lee,
D. Hershman, J. Omielan, and E. Prior
Outline
• Overview of yield loss prediction model
project (our approach to the challenge)
• Phase I: Brazilian study: verify
assumption about cause of yield reduction
• Phase II: KY and LA model development
- FL and KY quantification of role of SBR
lesions
• Phase III: FL model validation study
• Phase IV: Software development
• What’s next?
• What have we learned so far?
Challenge
 Develop a yield loss prediction model
for soybean rust under U.S.
conditions
 Project funded in Fall, 2005
Southern Region at Most Risk
Fig. 1. Probability of at least 15 consecutive days of suitable
conditions for P. pachyrhizi infection between July 1 and Sept 30.
Hatched areas indicate major or minor soybean production areas.
Source: R. Magarey, USDA/NCSU
Image Source: http://www.farmassist.com/soybeanrust/Navigation.aspx?nav=probability.html
November 8, 2006
Crop Physiology Perspective
combined with Plant Pathology
Integration of various
levels of organization
Temporal Changes and Disease
Yield
Yg = Yb X HI
Yb =  (Q X Ia
X
ε) dt
Rust causes premature defoliation
Healthy Canopy
Rust causes premature defoliation
Infected Canopy
Yield
Yg = Yb X HI
Yb =  (Q X Ia
X
ε) dt
Objectives
I.
Check assumption: Is SBR-induced
yield loss due to defoliation injury?
II.
Model building: Develop and validate
a model that can effectively predict
SBR-induced yield loss
Yb =  (Q X Ia
X
ε) dt
Objective: Determine the role of defoliation injury
on SBR-induced yield loss
Embrapa Soja, Londrina, Brazil
Phase I. Role of Defoliation injury
in yield loss? Londrina, Brazil
Cultivar BRS 154 (MG VII)
Rows 45 cm (~18 inches)
Planted December 19, 2005
& December 11, 2006
February 4, 2006
First flower
Materials and Methods
• RCBD design, 6 replications
• Five treatments
1. SBR - R1
Materials and Methods
• RCBD design, 6 replications
• Five treatments
1. SBR - R1
2. Mimic “SBR” at R1
Materials and Methods
• RCBD design, 6 replications
• Five treatments
1. SBR - R1
2. Mimic “SBR” at R1
3. SBR - R5
Materials and Methods
• RCBD design, 6 reps
• Five treatments
1.
2.
3.
4.
SBR - R1
Mimic - R1
SBR - R5
Mimic - R5
Materials and Methods
• RCBD design, 6 reps
• Five treatments
1.
2.
3.
4.
5.
SBR - R1
Mimic - R1
SBR - R5
Mimic - R5
Control
Materials and Methods
• Measured Leaf Area Index
• Disease severity
• Yield
Results and Discussion
Disease severity over time in 2007
100
Control
SBR at R1
Mimic SBR at R1
SBR at R5
Mimic SBR at R5
Disease Severity (%)
90
80
70
60
50
40
30
20
R5
R1
10
0
40
50
60
70
80
Days After Planting (d)
90
100
Plants infected at R1, leaf area over
time in 2007
5
4.5
4
Leaf Area Index
3.5
3
2.5
R2 = 0.94
Control
2
SBR at R1
R2 = 0.99
Mimic SBR at R1
1.5
2
R = 0.99
1
R1
0.5
R5
0
45
55
65
75
Days After Planting (d)
85
95
Role of defoliation injury in yield
loss?
VS.
SBR-infected plot (SBR at R1)
Mimic SBR at R1
Fungicide treated, and manually
defoliated to mimic SBR- plots
Plants at R5
Role of defoliation injury in yield
loss?
VS.
SBR-infected plot (SBR at R1)
Mimic SBR at R1
Fungicide treated, and manually
defoliated to mimic SBR- plots
Plants around R6
Impact of SBR on yield in
2007
SBR
Manual defoliation
4000
3500
Yield (kg ha -1)
3000
2500
2000
1500
1000
500
0
SBR at R1
SBR at R5
Control
Relationship between LAD and yield in
2006 and 2007 combined
3500
3000
R2 = 0.542
Yield (kg/ha)
2500
2000
LAD
Linear (LAD)
1500
1000
500
0
0
20
40
60
80
100
LAD (LAI x Days)
120
140
160
Non-abscised SBR-infected leaf
Healthy leaf area index (HLAI)
HLAI = LAI minus % diseased leaf area
Relationship between healthy leaf area
duration and yield in 2006 and 2007
combined
3500
3000
2
R = 0.7043
Yield (kg/ha)
2500
2000
HLAD
Linear (HLAD)
1500
1000
500
0
0
20
40
60
80
100
HLAD (HLAI x Days)
120
140
160
Summary from Brazil
• SBR-induced yield loss was dependent
on plant growth stage
SBR
3500
3000
Yield (kg ha -1)
2500
2000
1500
1000
• Lesions on non-abscised leaves have an
important impact on yield
500
0
SBR at R1
SBR at R5
Control
120
100
2
R = 0.7492*
Yield (gm-2)
80
60
40
20
0
0
20
40
60
80
Healthy Leaf Area Duration (HLAI d)
100
120
Phase II. Model Development
• Must relate yield to HLAI
• Experiments conducted in Baton Rouge, LA (Louisiana
State University), and Lexington, KY (University of
Kentucky).
• Weekly defoliations (0%, 33%, 66%, 100%) after R5
• LSU, MGs IV and V, row width 38”
• UK, MGs III, and IV, row width 14”
33% HLAI
100% HLAI 66% HLAI
0% HLAI
Relative Yield Response to Defoliation (UK) in 2006
100
Asgrow 3905
% of Control Yield
80
66% HLAI
60
33% HLAI
0% HLAI
40
20
R6
R7
0
10
15
20
25
30
35
Days after R5
40
45
50
55
HLAD vs Yield for Asgrow 3905
6000
5000
Yield (kg/ha)
4000
Control
100% Defol.
3000
66% Defol.
33% Defol.
2000
1000
0
0
50
100
150
200
HLAD from 6 to 44 days after R5
250
300
Relative Yield Response to Defoliation (LSU) in 2006
100
Pioneer P95M80
% of Control Yield.
80
60
66% HLAI
33% HLAI
0% HLAI
40
20
R6
R7
0
5
10
15
20
25
30
Days after R5
35
40
45
50
55
HLAD vs Yield for Pioneer P95M80
5000
Yield (kg/ha)
4000
3000
Control
100% Defol.
66% Defol.
33% Defol.
2000
1000
0
0
50
100
150
HLAD from R5 to 42 Days After R5
200
250
What is the effect of necrotic
lesions on plant productivity?
Objective: Impact of SBR Lesions on
plant productivity
• 2006 Study in Quincy Florida (Univ.
of Florida)
– North Florida Research and Education Center
• Cultivar: DP 7220-RR
• Row width: 36”
• Fungicide: Headline SBR
Measurements
• Selected leaves that showed a variation in
disease severity
– 2nd or 3rd central trifoliolate from the top
• Growth stage R6
• Net photosynthetic rate
• % disease on leaflet
Results and Discussion
100% Full photosynthetic capacity
W10 100%
75% Full photosynthetic capacity
– 75%
% of healthy leaf (x9)
50% Full photosynthetic capacity
35% Full photosynthetic capacity
w300 = 35% of healthy leaf
3% Full photosynthetic capacity
X20 = 1% of healthy leaf
Impact of SBR lesions on
photosynthesis
1.4
Relative Photosynthetic Rate
1.2
1.0
0.8
y = 0.878e-0.1071x
R2 = 0.8023
0.6
0.4
0.2
0.0
0
5
10
15
Disease Severity (%)
20
25
How do we quantify the effect of
SBR lesions?
• Develop a Bastiaans coefficient (β). This
is a mathematical coefficient that reflects
the impact of lesions on photosynthetic
capacity.
• The β coefficient, when combined with
HLAD data can be used to calculate an
“effective leaf area duration” (ELAD)
Phase III: Validate the Model
• 2007 Study in Quincy, FL
– Split-split plot design
– Row widths (15” and 30”)
– Determinate and Indeterminate varieties
(MG V)
– Disease levels:
• Disease-free control (using Folicur)
• SBR starting at R5
• SBR starting at R6
Plots in early September
Plots in early October
Measurements
•
•
•
•
•
Plant phenology through season
LAI, LI, disease severity through season
Photosynthetic capacity at R6
Harvest Index
Combine seed yield
The people that make it
happen.
Phase IV: Software
Development
Project Web Site
What’s next ?
• Continue to develop a Bastiaans coefficient (β).
The β coefficient, when combined with HLAD
data can be used to calculate an “effective leaf
area duration” (ELAD)
• Analysis of 2007 data from KY, LA, and FL.
• Further trials in 2008 and development and
deployment of yield loss prediction tool.
What have we learned so far?
• Phase I. Verify role of defoliation injury
– Yield loss models must account for both defoliation injury
and rust lesions on non-abscised leaves
• Phase II. Model Development
– Yield is a function of healthy leaf area duration
– We expect that ELAD will give a more robust SBR yield
loss model since it will account for both defoliation injury
and rust lesions on non-abscised leaves
What have we learned so far?
• Phase III. Model Validation
– Still in process
• Phase IV. Software Development
– Visit our Project Website for updates
– http://www.uky.edu/Ag/Agronomy/Department/sbr/
Additional funding from:
and Southern Soybean Research Program