CAAREA breeding-related activities
Resistant varieties and role of plant health in
Aflatoxin control
Presenter:
Dr. Arnold Mushongi
ARI-Uyole
CAAREA Tanzania Project Leader
Maize research status in developing countries
Losses of maize grain yield due to
various stresses in the developing
world
•Lost to stem borers
= >10%
•Lost to post harvest pests = >15%
•Total insect pests = >25%
Loss of quality less studied!!!
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Background in Tanzania
• Tanzania people: 44 million
• 85% of Tanzanians depend on maize
• 60% dietary calories, 50% daily protein; maize also cash
crop; multiple uses (including feed)
• Per capita consumption: annual 112.5kg
(308g/person/day); national utilization ~3million
metric tons(TFSD, 1996); GY = 3.66mt [FAOSTAT 2007]
i.e. production ~ consumption
• very low maize productivity: <1.5t/ha vs potential of
8t/ha due to multiple factors --- use 9kg/ha fertilizer
(AFS, 2006), poverty, unstable climate, etc
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More and more Varieties needed that:
• A. Yield higher
• B. Are safe for human and livestock consumption
– Plant health is key in achieving a) and b) above, since
a stressed genotype will succumb to the stressors
and consequently ill performance
• Achieving a) and b) will contribute to improving
national food security, alleviate poverty
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Current interventions
• Two breeding projects on maize
• I. On improved production and productivity
• II. Food safety and human nutrition
– Challenge: chances are limited to have varieties that
have outstanding higher yields and are aflatoxin
resistant
– Efforts done to strike a balance
– Note further that no crop variety in Tanzania are
proven to be resistant to aflatoxin accumulation
(TOSCI, 01 December 2012 – pers. comm.)
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Project I: AGRA
• Title: Towards improvement and adoption of African
Crops: Production, testing, promotion and distribution of
seeds of improved hybrid Maize cultivars in the
intermediate and transition-to-low altitude zones of
Tanzania
• Goal: To improve national food security and the
livelihoods of poor rural farmers through access
to new improved maize cultivars and an efficient
quality seed production and distribution system
in Tanzania
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Key activities
 Inbred-hybrid generation and evaluation
 Maintenance breeding
 Population improvement
 Production of breeder and pre-basic seed for ASA
and private sector
 Promote and use participatory maize breeding
 Convening meetings embracing PPP approach in the
local seed industry
 Extension messages on good agronomic practices
for maize production
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Targeted traits
• High grain yield
• Early maturity
• Mitigating consequences of climate change
– Drought tolerance
– Striga weed tolerance
– Maize streak virus tolerance
– Early maturity
– Other key biotic and abiotic stresses
– Market traits i.e. end user preferences
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Project II specifically on breeding for resistance to
Aflatoxin accumulation: Milestones
• 16 in total
– Subdivided mainly to:
1. interacting with key stakeholders
2. National wide survey
3. Human/staff and institutional support
4. Field trials (inoculated and uninoculated)
5. Biobanking, manuscript publications
6. Strategic (culture of moving from Data to decision
making) --- success of CAAREA !!!!!
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… Breeding target: GY + MA
tolerance/resistance
• Eco-biological + socioeconomic issues: drought, low soil
fertility (N), high temperature, insect/disease resistance
(pre, postharvest), farmers preferences, etc
• Traits: GY components, tight husk cover, closed ear tips,
flintier kernels, long EFPD, fast KDD, earliness, drooped
ears, etc
– Secondary traits targeted due to low heritability of
aflatoxin accumulation cf. other types of mycotoxins
– Implication: highly influenced by GxE interaction,
more environments required to validate results
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Ear/kernel rots
A. Flavus and A. parasitucus produce aflatoxins
•
•
•
•
•
•
•
Pre-harvest: Maize ear
samples (250)
collected from 10 sites
(low and highland
maize)
Period: June-July 2012
Post-harvest: same
sites
Period: SeptemberOctober 2012
Trials planted at in two
planting regimes in two
sites with A. flavus
(Table 1)
Secondary traits bred
for and evaluated by
MSc student in lowland
maize
NxP fertiliser trial done
by another MSc
students in the
Southern Highlands
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Continous work: Field trial panels,
planting, modeling
• Field trial (inoculated)
– 40 entries (20 inbred lines, 10 highly advanced
experimental hybrids, 10 very popular commercial
hybrids)
– FT uninoculated 10 popular varieties per agro-zone
i.e. 20 experimental stations across Tanzania
– data collection: weather, phenotypic
– data analysis, modeling, risk maps-aflatoxin, stresses
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Automatic weather station at trial site
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Table 1: Laboratory results of fungal
isolates (%)
Site
Aspergillus
flavus
niger
carbonareous
Igeri (Njombe)
13.4
7.4
14.8
Seatondale (Iringa)
2.2
0
0
Mbimba (Mbeya)
0
0
0
Ismani (Iringa)
0
0
0
Milundikwa (Rukwa)
0
0
0
Mitalula (Mbeya)
0
0
0
ARI-Uyole (Mbeya)
0
0
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0
Capacity building
•
•
MSc students (Christine Kaswahili, Sokoine University of Agriculture; and
Samuel Msuya, Open University of Tanzania;
Nursery crossing block at ARI-Ilonga (Dr Mushongi and MSc student Ms
Christina Kaswahili)
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From R. Nelson, Cornell University
From R. Nelson, Cornell University
From R. Nelson, Cornell University
Aflatoxin level tested inbred lines (CAAREAKenya)
0-20ppb
20-100ppb
Above 100ppb
Inoculated maize genotypes (entries)
FT2FT2 analysis beginning January
overlap of genotypes in Tanzania  quicker, more confident answers
analysis beginning Januarynotypes in Tanzania  confident answers
Potential opportunities for scaling up
• Successful models developed from this project would
be applied to
– other crops where aflatoxin is a problem
– as decision support systems along the nodes of crop
value chain
– reliably predict and demarcate target population of
environments as hotspots for breeding goals against
aflatoxin accumulation (including other mycotoxins in
other food and feed systems)
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……Potential opportunities for scaling up
• Human and institutional capacity building would foster national
efforts to mitigate the problem in long run
• Sustainable impact would result from the approach emphasized
by AGRA of promoting the PPP approach in the local seed
industry; breeding and releasing new varieties; and cooperation
with local government, ASA and TOSCI.
– For instance from the CAAREA research outputs, TOSCI would
be advised to include a criterion of resistance/tolerance to
aflatoxin in major crops before their varieties are released
while ASA and the private sector could popularize use of such
varieties.
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