Synergistic Effect of Resistant Maize Synthetics and Aflasafe Application
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Transcript of Synergistic Effect of Resistant Maize Synthetics and Aflasafe Application
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
Synergistic Effect of
Resistant Maize Synthetics
and Aflasafe Application
Joseph Atehnkeng
For the team
Development of aflatoxin-resistant varieties
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
Breeding may target:
• Direct selection for resistance to fungus and
aflatoxin accumulation
• Indirect selection for resistance or tolerance to
biotic and abiotic stresses.
• Selection for morphological traits such as ear,
kernel, and husk characteristics that impede
or delay fungal introduction or growth.
Technology-implementation challenges
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
• Accumulation of aflatoxins in maize occurs following a complex
series of interactions
• Among maize
• The environment
• The pathogen
• insects
• Crop-management practices.
• Selection must be done simultaneously for multiple stresses in
order to combine drought and heat tolerance, resistance to
insects (especially ear-feeding insects), and resistance to the
pathogen.
• These stress tolerances must be combined with improved
agronomic performance in new maize varieties for adoption of
aflatoxin-resistant cultivars to occur, as farmers will not grow low-
yielding varieties regardless of aflatoxin resistance.
334 396 400 488 800 809 816 956
5474 5671
6438 6087
5685
7115
6040 5891 5743
5662
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
Hybrids
Aflatoxin (ppb)
Grain yield (kg/ha)
Afl
ato
xin
(p
pb
)
Gra
in y
ield
(kg
/ha)
Less Aflatoxin Susceptible, High-Yielding Yellow Maize Hybrids
Less toxin – high yield
Product: Aflasafe
Mixture of 4 native atoxigenic strains
Nigeria
How Does aflasafe Work?
Broadcast
@ 10 kg/ha 2-3 weeks
before flowering
Sporulation on moist soil
Spores
Insects
Aflasafe in 5 kg boxes
3-20 days
Wind
Soil
colonization
30-33 grains m-2
Fungal network in killed grain
75
94 100
0 3
39
73
27
0
20
40
60
80
100
120
<4 <10 <20 >20
Nestlé/EU WFP/Nigeria US Unsafe
Maximum allowable aflatoxin level (ng g-1)
Farm
ers
' fi
eld
s (
%)
Treated
Control
Different Levels of aflatoxin
in AflaSafe™ treated and
untreated fields at harvest
Objective
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
• To evaluate the combined effect of
aflasafeTM and aflatoxin resistant
hybrid to reduce aflatoxin reduction.
Field Layout
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
10 x 7.5 m
Alley
Alley Alley
Alley
Alley
Alley
10 x 7.5 m
Treated area with aflasafe
Untreated area
•2010 = 3 location
•2011 = 9 locations
• Maize varieties
• AFLTOXINRSYN3-W
• AFLTOXINRSYN2-Y
• AFLTOXINRSYN2-Y
•TZB-SR
• Replicated 6 times
• Aflasafe applied at 40
DAP
A t Maturity
• 25 maize cobs collected
from each plots at harvest
• Analyzed for aflatoxin
Biocontrol x Resistance
Experimental variety
At harvest
Control Aflasafe
RSYN2-Y 19.6 1.7
RSYN3-W 6.9 1.8
SYN3-Y 18.4 1.7
TZB-SR (susc.) 57.5 4.7
After poor storage
Control Aflasafe
462 44
627 38
387 19
1152 163
Combining management tactics increases extent of aflatoxin reduction
Aflatoxin (ppb) in Low-Aflatoxin Maize Lines With and Without Aflasafe Treatment
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
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Experimental varieties
Aflatoxin reduction (%)
Resistance alone
Biocontrol alone
Resistance + Biocontrol
RSYN2-Y 66 (60) 91 (90) 97 (96)
RSYN3-W 88 (46) 74 (94) 97 (97)
SYN3-Y 68 (66) 91 (95) 97 (98)
TZB-SR (Susc.) 58 (1152) ppb 92 (86)
% Reduction in experimental varieties compared to susceptible variety (TZB-SR) under natural conditions
% Reduction in varieties with biocontrol compared to susceptible variety (TZB-SR) under natural conditions
% Reduction in biocontrol treated plots compared to control plots of the same experimental variety
% Reduction in varieties with biocontrol compared to susceptible variety (TZB-SR) under natural conditions
% Reduction in biocontrol treated plots compared to untreated plots of the same variety
Synergistic Effect of Resistance and
Biocontrol in Reducing Aflatoxins at Harvest and after poor storage
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Aflasafe and Cultivar Interactions
Experimental variety
WithoutAflasafe
With Aflasafe
Reduction (%)
RSYN2-Y 18 (aA) 0 (aB) 100 (a)
RSYN3-W 57 (bA) 2 (bB) 96 (b)
SYN3-Y 36 (aA) 0 (aB) 100 (a)
TZB-SR (susc.) 67 (bA) 3 (bB) 96 (b)
Aflatoxin (ppb) in Low-Aflatoxin Maize Lines With and Without Aflasafe Treatment in Shika
Means within a column with same lowercase letter, and means of treated-control pairs
within a row with the same uppercase letter are not significantly different; P < 0.0001
Nestle visit 23-24 Jan . 14
Conclusion
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
A combination of the two technologies
reduces aflatoxins by more than 90 %
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
Thank you
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
Background
• Pre-harvest host resistance
• Though commercial varieties are not yet available
effort are in progress
Experiment layout
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
•In Kaduna State
• In 2010 = 3 locations
• In 2011 = 9 locations
• Maize varieties
• AFLTOXINRSYN3-W
• AFLTOXINRSYN2-Y
• AFLTOXINRSYN2-Y
• TZB-SR
Generation of resistant germplasm
www.iita.org A member of CGIAR consortium Nestle visit 23-24 Jan . 14
Methods to achieve resistance to A. flavus and
aflatoxin accumulation include:
• Prevention of fungal infection of maize, which is
especially important under stressed environmental
conditions
• Prevention of subsequent growth of the fungus
once infection has occurred
• Inhibition of aflatoxin production following
infection
• Degradation of aflatoxins by the plant or fungus.