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Wheat yield losses due to rusts and powdery mildew
presented By
Dr. M. Abdelkader
-Rust diseases of wheat and powdery mildew causes significant yield
losses . -The damage caused depends upon the severity and time of infection
resulting into yield reduction. -Estimates yield losses of cereals caused by rusts since 1918 are
maintained by the United States Department of Agriculture Research Service Cereal Disease Laboratory in St. Paul,
Minnesota . -Wheat stripe rust in the CWANA countries causing severe yield losses
more than 70% in 2010. -leaf rust can cause grain yield losses higher than 50% in severe
epidemics.
-In Australia stem rust cause losses up to 37% in 1992.
-In 1995 wheat stripe rust caused yield losses ranged from 14 to 26% in
delta region in Egypt, while the national loss was about 10%.
-Wheat rusts under the Egyptian condition was the main cause to discarded some varieties such as Giza 139,144,150 sakha 8, 69, Gemmiza-1 and 5.
Disease infection leads to
- Complete damage to the economic part ( loose smut)
- Partial damage to the economic part
(covered smut) .
- Damage to the other parts (down mildew, powdery mildew, leaf spot
and rusts)
Missing plants (damping –off,
wilt) No
yield
Yield losses estimation
-Total yield ( yield per plot )
-Single plant (gm.)
-1000 -Kernel weight (gm.)
-Test weight
Yd
Loss % =1- ------- x100
Yh
Where: Yd = yield of diseased plants
Yh = yield of healthy plants (Calpouzos et al., 1976).
Factors Affecting Yield Losses
1 -Varietal susceptibility (S-Ms-Mr-R).2 -Time of disease appearance (which growth stage) .
3 -Environmental conditions( temperature and relative humidity.(
For good experimental yield losses
1 -Using fungicides to protect the control plots. 2 -Inoculation at different dates.
3 -Inoculation with different inoculum level.4 -Host predisposition.
Why we do estimate
Yield loss
To estimate the Economic Significance of the disease
ByRelating the disease
infection To yield loss
To determine the economicThreshold at which the
control measurement is applied
To evaluate the genetic Level of resistance in
A variety
Relationship between stem rust severity, wheat growth stage, and percentage of yield loss.
BootFlowerMilkEarly
dough
Late
dough
Ripe%
Yield
loss
----trace50.0
---trace5100.5
--trace510255.0
-trace510254015.0
trace51025406550.0
51025406510075.0
10254065100100100.0
Roelfs (1992)
Relationship between leaf rust severity, wheat growth stage, and percentage of yield loss.
Pre-tillering
JointingBoot to heading
Flowering
MilkEarly dough
%
Yield
loss
--trace1025401
-trace102540403
trace102540656510
1025406510010020
25406510010010035
406510010010010050
10010010010010010095
Chesters (1946)
100 grain samples
infected seeds Healthy seeds One pustule
10000 spores
One pustule
3000 spores
Yield Losses due to stem rust infection
Cultivar
1000 grain weight
2009/2010
1000 grain weight
2010/2011
Disease severity
Inf. (gm)Prot. (gm)
Reduction %
Disease severity
Inf. (gm)Prot. (gm)
Reduction %
Sakha 85 S40 .2740.400.32120 S39.1143.179.4
Giza 16020 S38.1942.4710.0720 S28.0734.5818.82
Giza 1645 S38.4640.835.810 S30.3834.3311.50
Gemmiza 3Tr S40.0540.260.5215 S50.3552.o40.363
Yield Losses due to leaf rust infection
Cultivar
1000 grain weight
2009/2010
1000 grain weight
2010/2011
Disease severity
Inf. (gm)Prot. (gm)
Reduction %
Disease severity
Inf. (gm)Prot. (gm)
Reduction %
Gemmeiza-780 S43.23848.65611.13580 S40.11948.32817.138
Gemmeiza-1070 S40.25845.04710.63180 S37.23845.65618.240
Gemmeiza-1170 S52.05954.3284.17670 S51.33254.2575.391
Sakha-9380 S41.89547.7769.81580 S39.47746.08914.346
Yield Losses due to stripe rust infection
Cultivar
1000 grain weight
2009/2010
1000 grain weight
2010/2011
Disease severity
Inf. (gm)Prot. (gm)
Reduction %
Disease severity
Inf. (gm)Prot. (gm)
Reduction %
Gemmeiza-530 S32.0041.67723.2120 S46.7251.128.6
Sakha-850 S27.12342.536.1840 S37.3643.5514.21
Sakha-6940 S28.7942.46032.1930 S31.33245.25730.07
Giza-16080 S25.54142.77639.11250 S32.742.5423.13
Yield Losses due to Powdery mildew infection
Cultivar1000 grain weight
2010/2011
Disease severity%
Inf. (gm)Prot. (gm)Reduction%
Gemmeiza-74034.1137.7339.59
Gemmeiza-109028.37334.0716.72
Sakha-935034.0937.779.73
Giza-1606026.89331.2o13.81
How to reduce wheat yield losses
Planting Resistant Varieties
New races
Yr 9
Ug99
Yr27
1-Tolerant Varieties2-Slow Rusting Varieties
Agriculture Practes.
1-Sowing Dates .2-Sowing Density .
3 -Irrigation. 4-fertilization
Thank You
-Rust diseases of wheat and powdery mildew causes significant yield
losses . -The damage caused depends upon the severity and time of infection
resulting into yield reduction (S. Ahmad et al., 2010). -Estimates of yield losses of cereals caused by rusts since 1918 are
maintained by the United States Department of Agriculture Research Service Cereal Disease Laboratory in St. Paul,
Minnesota (Chen et al., 2004).
-Wheat strip rust in the CWANA countries causing severe yield losses
more than 70% in 2010. -leaf rust can cause grain yield losses higher than 50% in severe
epidemics (German et al. 2007) . -In Australia stem rust cause losses up to 37% in 1992 .
-In 1995 wheat strip rust caused yield losses ranged from 14 to 26% in
delta region in Egypt, while the national loss was about 10% (El- Daoudi et al., 1996) .
-Wheat rusts under the Egyptian condition was the main cause to discarded some varieties such as Giza 139,144,150 sakha 8, 69, Gemmiza-1 and 5.