Presented by Francis Muthoni, Justus Ochieng, Jean-Marc Delore, Phillipo J. Lukumay, and Inviolata Dominic at the Power on Your Plate Summit, Arusha, Tanzania, 25-28 January 2021.

1. Extrapolation suitability for improved vegetable
technologies in Babati District, Tanzania
Francis Muthoni1, Justus Ochieng2, Jean-Marc Delore1 & 3, Phillipo J. Lukumay2, and Inviolate Dominic2
1International Institute of Tropical Agriculture, 2WorldVeg Centre, 3Wageningen University & Research
Power on Your Plate Summit
25-28 January 2021, Virtual and In-person, Gran Meliá Arusha, Tanzania

2. Outline
• Introduction
• Experimental trials of elite vegetable cultivars
• Generating Extrapolation Suitability Index (ESI)
• Relevance of ESI maps in scaling programs
• Future plans

3. Introduction
• Vegetables are important dietary component rich in essential micro-
nutrients & source of income.
• Investment on sustainable vegetable production technologies enhance
societal benefits & environmental sustainability.
• Two improved vegetable cultivars grown under integrated management
practices (IMP’s) in Babati district of Tanzania produced double the yield
and net income compared to standard farmer’s practice.

4. • Where to scale-out high yielding cultivars + IMP’s with minimal risk of
failure?
• Solution: Leverage geo-spatial technology & digital agronomy.
• Generate maps on risk of extrapolating to new areas.

5. Study area in Babati, Tanzania
• On-farms trials of tomato (Tengeru-10) and African Eggplant (Tengeru
white).
• Four villages representing agro-ecological zones since 2013.

6. Validation of improved vegetable technologies
• On-farm trials compared cultivars produced under integrated
management practices (IMP) & standard farmers’ practice (control).

7. Yield & income from on-farm trials
• Yield & income of tomato (Tengeru10) and African eggplant (Tengeru-
white) under integrated management practices (IMP) double compared
to farmers practice.
IMP had >double yield
& income compared
to farmer practice
(control).
Where else to scale
out two cultivars with
IMP to replicate
success?

8. Input data for developing ESI
• Integrate on-farm trials (reference) & gridded remote sensing
(projection) data.

9. Characterizing reference environments
• Homogeneity of environmental conditions in field trials examined with
HPCA.
• Discriminated 3 clusters representing population of target environments.
Magug
u
Galapo
Bermi
Seloto

10. Selection of reference target environments
• Yield & income from different environmental clusters compared to select
the best-bet reference trial sites for extrapolation of vegetable cultivars.

11. Mapping ESI for Vegetable cultivars
• ESI ranges from 0 to negative infinity with 0 being the most suitable
• Tengeru 10 widely adapted but African eggplant unsuitable in southwest
Babati.

12. Most important covariates (MIC)
• Tengeru 10 largely limited by Evapo-transpiration (ETP) and elevation
(DEM).
• Tengeru-white mainly limited by precipitation (PPT) and market access.
• Soil water conservations measures & supplemental irrigation
recommended.

13. Significance of ESI maps
• Extrapolation suitability (ESI) maps produced to guide extension &
development partners on priority sites for targeting scaling intervention.
Application of ESI maps expected to:
• Reduce the risk of failure,
• Prioritize allocation of scarce resources for maximum impact, and
• Possibly enhance adoption at scale.

14. Future developments
• Design of a simple & user-friendly mobile-based tool for farmers and
extension staff with basic phones.
• Integrate suitability maps with Mwanga Platform for digital agronomic
advisory.

15. Africa Research in Sustainable Intensification for the Next Generation
africa-rising.net
This presentation is licensed for use under the Creative Commons Attribution 4.0 International Licence.
Thank You