This document summarizes research on specialized sweet potato vine multiplication in Tanzania. It found that farmers who were trained as decentralized vine multipliers (DVMs) adapted new skills into their existing practices. Most DVMs continued multiplication, using improved techniques like rapid multiplication and off-season root production. However, some stopped due to issues like wildlife damage or lack of water. DVMs developed a dual pricing system and sourced improved varieties. The research suggests specialization may be emerging in seed production and tasks may separate within the seed system. Continued support is needed to understand local markets and ensure sustainability.

1. Specialised
sweetpotato vine
multiplication in Lake
Zone, Tanzania: what
“sticks” and what
changes?
Margaret McEwan, Lusheshanija D., Shikulu, K., and Sindi, K.
1 International Potato Center, SSA. 2 MoARD, Tanzania.
3 Wageningen University, Netherlands. 4 International Potato
Center, Rwanda.
APA, Addis Ababa, Ethiopia, 9-12, October 2016.

2. Background
Slide No. 2
• Farmers obtain seed from many sources
• What happens when farmers are trained as vine
multipliers?
– What is role of a specialised vine multiplier?
– Is there uptake of new knowledge and skills, if so, how
are these adapted into existing seed system practices?
• “Marando Bora” (better vines) component of
SASHA trained 88 individual farmers and
farmer groups as “decentralised vine
multipliers” (DVMs)
– Conservation, and multiplication technologies, pest &
disease identification and management,
– Distributed improved planting material through a
subsidised voucher system to 85,000 farmers – 76%
women. Local multiplier and farmer sourced materials,
Sengerema. Tanzania. Credit: M. McEwan

3. Methods
Slide No. 3
• Mixed methods:
– March 2013: formal survey of 88 DVMs. 9 months
after intervention ended
– Semi-structured interviews and observations with
sub-group of 12 DVMs and 21 farmers: 2010 –
2013
Type of
DVM
%
(n=88)
% Female
Group
DVMs
72% 68%
Individual 28% 28%
Experience
of sale of SP
vines
18%
Rywamwezi DVM Musoma Rural:
Credit. M.McEwan
Source: DVM module endline survey
2013

4. Research questions
Slide No. 4
• What differences are there between
farmers and multipliers:
– Characterisation of quality planting material?
– Varieties and seed sourcing?
• How have multipliers used and adapted
technologies promoted by the project?
– Multiplication techniques; irrigation practices;
fertiliser use
• Current status of multiplication and
reasons for continuing or stopping
RMT beds, KIMKUMAKA, Credit: M. McEwan.
Fertiliser application: Umoja DVM, Bunda. Credit. L. Laizer

5. Results: differences in knowledge &
practices
Slide No. 5
Farmers & multipliers: Association Changes in knowledge & practice
among multipliers
Quality cues:
General condition, age of plant,
visible signs of pests & diseases;
Root production; Spread of disease to other plants;
Different effects of different diseases;
Seasonal patterns; Latent disease;
Interactions among multiple factors:
disease, fertility, variety
Vigour: Stem thickness, inter-
nodal length
Speed of sprouting;
Varietal differences;
Site selection:
Shift between lowland areas (July-
November) & upland areas
(February – June)
Conservation of
planting material &
off season root
production
Rent of suitable land; use of irrigation
(August-September); group based
strategies.
Seed sourcing:
Friends, neighbours & relatives
Easy access, “free”
with moral & social
obligations
Improved varieties: sourced through
NGOs, research, other multipliers.

6. Results: multiplier status &
multiplication technology
Slide No. 6
Type of DVM %
multiplying
for next
season
Multiplication technology
Rapid
Multiplication
Roots &
Vines
Both
All DVMs 69% 34% 61% 5%
Individual DVMs 88% 36% 59% 5%
Male individual 83% 40% 53% 7%
Female individual 100% 27% 71% 0
All group DVMs 62% 33% 62% 5%
Female majority
groups
58% 50% 39% 11%
Male majority groups 60% 22% 88% 0
50:50 groups 75% 11% 89% 0
Source: DVM module endline survey
2013

7. Results: multiplier irrigation
& fertilizer use
Slide No. 7
Type of DVM % using
irrigation
Fertiliser use
Any Pump During
project
After project
All DVMs (88) 97% 34% 89% 26%
Individual DVMs (25) 100% 44% 80% 20%
Male individual 100% 61% 89% 28%
Female individual 100% 0 57% 0%
All group DVMs (63) 95% 30% 92% 29%
Female majority
groups
100% 39% 97% 33%
Male majority groups 93% 29% 87% 20%
50:50 groups 92% 9% 92% 33%
Pump: treadle (12%) or motor (23%)
Treadle pump and watering can
irrigation methods: Credit. L.
Laizer & M.McEwan
Source: DVM module endline survey
2013

8. Results: intention & practice to
continue multiplication
Slide No. 8
• March 2013: 69% were currently
multiplying
• Intention and practice depends
on
• Season (short rains or long rains)
• Objective: vines only or vines and roots
• Individual circumstances: need to
identify alternative site, family illness,
group dynamics
• Stated reasons for abandoning
multiplication:
• Wildlife damage; flooding or lack of
reliable water source
• Group dynamics
• Local tradition and culture not conducive
to selling of vines
• Community thinks that vines should
continue to be subsidized or that there
is not market for vines without vouchers
• Stated reasons for continuing:
• The need for “marando bora” in the
community was high
• Income generation from roots and vines
• Project: Tsh 600 for 200 cuttings
• Post project: Tsh 1,166 for 200 cuttings

9. Discussion
Slide No. 9
• How and when do we define that a seed enterprise is
“sustainable”?
– Local context – cultural practices around exchange of vines,
willingness to pay, market, agro-ecology, particular season
• DVMs adapted some technologies into own system – by
choosing appropriate time to use RMT in the off season
(August – September) and not all year round
• Process of skilling and specialization in agrarian change
– Is specialisation of seed production emerging?
– Is it leading to separation of root and vine multiplication cycle?
• Maintenance of separate seed stock (role of net tunnels)
– Implications for seed quality and resilience in seed systems?

10. Conclusions
Slide No. 10
• Dual pricing system emerging: local & improved
• Female group DVMs continued to use new
knowledge & skills
– Women better able to access project support through
working in groups rather than individuals. Influence of
“moral economy”.
• Implications for further work
– Understanding context: the types of markets for vines, and
what affects sustainability
– Vigour & sprouting important attributes in quality planting
material
– Selection of multipliers and type of support required
– Segregation of tasks in seed system
– Scaling: getting varieties out
Tunu DVM, Geita. Credit M. McEwan