Use of visual inspection to inspect seed production fields of small-scale seed multipliers to improve physical and economic access to quality seed by smallholder farmers.
1. Visual inspection to manage bacterial wilt in
Sub-Saharan Africa:
Improving seed quality and impacting smallholder
farmers
Parker, ML, Mugo, J, Gutarra, L, Orrego, R and
Schulte-Geldermann, E.
European Association of Potato Research
Triennial Conference, Brussels July 7-11, 2014
2. Bacterial Wilt (BW) major
(principal) constraint to potato
production
BW = Ralstonia solanacearum
Massive host range (> 200 plant
species)
Survivor
Impact of bacterial wilt on smallholder farmers
Major cause of poor seed quality
and consequently, low yields
(8-12 t/ha)
3. Spread
seed tubers
contaminants
irrigation/water run-off
NO host resistance
NO chemical control
Management relies on:
clean seed
sound crop rotation
Management
4. Unavailable
Quality (formal) seed difficult to access
Expensive
Informal seed system dominates in SSA
farmer-saved seed
unmarketable tubers
Main culprit = SEED
5. Prevalence
Wide spread in SSA from low to high altitudes
Region Incidence
(%)
1500 -
2200 m
> 2201 m Region Incidence
(%)
1500 -
2200 m
> 2201 m
Aberdares 0 6 5 Mau 0 1 4
1-9 1 4 complex 1-9 5 3
10-20 2 5 10-20 2 2
above 20 0 6 above 20 1 1
Elgon 0 4 6 Mt Kenya 0 6 3
1-9 2 2 1-9 2 0
10-20 3 4 10-20 3 1
above 20 1 7 above 20 4 1
BW was observed on 121 farms of a total 156 farms (78%)
6. Improving access to quality seed
Certification regulations exist, practice is minimal
In Kenya
quantities of certified (formal) seed supply
approximately 2% of demand
available at a few locations across the country
Costly
certify seed lots
purchase
7. tissue culture/minitubers/first field generations
onward, localised multiplication
decentralised multipliers
Improving access to quality seed
Formal certification
Quality Declared
Planting Material
QDPM
8. VISUAL INSPECTION by recognised committees
Removing infected plants from seed multiplication
plots (negative selection)
GAP - particularly crop rotation, alternative host
management and field hygiene
QDPM is promoted among decentralised multipliers
Thereby increasing geographic and economic
accessibility to quality seed
Local trade only
QDPM: an alternative approach to assess seed
health
10. VISUAL INSPECTION
Farm-saved seed
Marking and saving tubers from
the healthiest plants in a crop
for the following season’s seed
Positive selection
12. Another main culprit = poor rotation
Potato key (only!) cash
and food security crop for
farmers in mid to highland
regions
Season after season,
farmers plant potato on
same site
Lower altitudes, farmers
crop numerous
solanaceous crops
13. Improving crop rotation
Region Crop
CFU / g soil
Before planting After planting
Huanucalla Potato 188 11248
Onion 836 401
Chinchinga Potato 50 426
Onion 38 17
In each region, onion reduced CFU by ~ 50%
18. Improving effectiveness of visible inspection
Knowledge on Rs isolates
Simple tools for field based diagnostics
Further validation of rotation (onion) to reduce
Rs populations in soil
Understand infection
gradient from an infected
source