Developing a clean seed delivery system for
cassava and sweetpotato in Kenya
By Dr. Ruth Amata
Kenya Agricultural Research Institute
First Bio-Innovate Regional Scientific Conference
United Nations Conference Centre (UNCC-ECA)
Addis Ababa, Ethiopia, 25-27 February 2013

Participants
• Githiri Mwangi-JKUAT
• Ruth Amata - KARI
• Kamau Joseph-EAPP
• Elijah Ateka-JKUAT
• Kasina Muo - KARI • Ndolo Phillip-KARI
• Obiero Hannington-KARI
• Kuyia Joan-Ministry of
Agriculture • Mwaniki Shelmith-KARI
• Sila Martha-Ministry of • Kagondu Abed-KEPHIS
Agriculture • Kihurani Agnes-JKUAT
• Momanyi Violet- KARI • Agili Samuel-CIP
• Githunguri Cyrus-KARI • Odero Benard-CRS
• Wangai Ann - KARI • Mbugua Edward-GTIL
• Miano Douglas – KARI • Atuncha H-JKUAT
• Mamati Edward-JKUAT • Farmers
• Omari Jane -NCST

Introduction
• Cassava and sweetpotato - propagated through stems and vines
• Major challenge - lack of an effective system for availing clean
planting materials to farmers
• Major viral diseases - Sweet potato virus disease, cassava brown
streak and cassava mosaic virus diseases (transmitted through
infected plant material and cause losses of up to 70%)
• Over 98% of planting materials are disseminated through farmer
to farmer exchange and sale of cuttings in local markets
• Hence the need to develop an effective model for clean seed for
these 2 crops

Methodology
• Stakeholder interactive
discussions held at
workshops (KARI Kabete -
November 2011 / 2012)
• Participants - from different
cassava and sweetpotato
value chain levels
• Technology
developers, producers, proc
essors, consumers and
regulators

Methodology
• Participants - randomly assigned to 3 groups
• Review of existing tuber crop seed production
and distribution systems
• Constraints and opportunities identified
• Participants proposed 3 models from which 1
hybrid model was developed

Opportunities for a clean seed system
• Capacity in disease screening technologies
• Private sector laboratories - already involved in
multiplication - (Tissue culture)
• Policy review for the 2 crops is underway (Goodwill
from the government)
• Credit is available for commercialization of clean
seed production for cassava and sweet potato

Challenges for a clean seed system
• Lack of appropriate policies to enable clean seed
certification process and enforcement of
quarantine measures
• Lack of standards / thresholds to guide and
enhance the certification process
• lack of awareness of implication of using infected
material versus clean material

Figure 1. Model proposed by Group 1 participants at the
cassava/sweetpotato clean seed workshop held at KARI Kabete on
3rd May 2012.

Figure 2. Model proposed by Group 2 participants at the
cassava/sweetpotato clean seed workshop held at KARI Kabete on 3rd
May 2012.
Germplasm Collection &
NARS, KEPHIS Conservation
Screening/Pre-testing Infected material
NARS, KEPHIS for diseases
Only Clean
Cleaning
material
NARS, Multiplication of
KEPHIS tested/clean material = Confirmatory Testing
Starter/Breeder material for diseases
NARS, KEPHIS, Mass Multiplication of Mass Multiplication of
GTIL, MoA - ATCs tested material to get tested material by TC
Farmers/Farmer cutting/vines
Groups
Farmers getting
cuttings, vines or TC
material

Figure 3. Model proposed by Group 3 participants at the
cassava/sweetpotato clean seed workshop held at KARI Kabete on 3rd
May 2012.
Pre-testing
Elite lines/Consumer preferred varieties
PRODUCT
NARS, KEPHIS, CGIAR Cleaning & Confirmation
testing DEVELOPMENT
TC
PHASE
Mass multiplication
Breeder’s seed
TC
Multiplication of Multiplication of
breeder’s seed to breeder’s seed (TC) for
get cuttings further multiplication to
KARI, Regulators, get cuttings
Seed merchants,
COMMERCIAL
PHASE
Farmers getting TC
plantlets or cuttings
for planting

Figure 4. Hybrid Model agreed upon by participants at the cassava / sweet
potato clean seed workshop held at KARI Kabete on 3rd May 2012.
Testing and Pre-testing of elite /consumer
preferred material for diseases
PRODUCT
Cleaning DEVELOPMENT
Thermotherapy
PHASE
NAR’s , KEPHIS Cleaning and / cryotherapy
confirmation testing
Primary multiplication of tested/clean Indexing
material = Starter/Breeder material
Multiplication (Tissue culture/screenhouses)
NAR’s, KEPHIS,
MoA, Secondary Multiplication
Private sector isolated fields
(Starter/Breeder material )
COMMERCIAL
Supply
Tertiary Multiplication PHASE
in isolated fields
NARS, KEPHIS,
Private sector, MoA,
Farmers / Farmer
groups Farmers getting cuttings, vines or tissue culture material

Implementation of the cassava/sweetpotato clean seed model
Testing and cleaning
Players;
KARI Njoro / KEPHIS
Primary multiplication
Players;
• Genetics Technology
International Limited (GTIL)
• KEPHIS

Implementation of the cassava/sweetpotato clean seed
model
Secondary multiplication;
• GTIL; Farmer groups-
Mutomo farmers group (2
CBO’s-Eastern; Western)
• KEPHIS
Tertiary multiplication;
• 5 individual farmer
multipliers - Rift Valley(1);
Eastern-2; Western:1
• KEPHIS

Way forward
• Conduct cost analysis of the seed model
• Sensitize farmers on the need for clean planting
material
• Lobby the Government for policies to enhance clean
seed certification for cassava and sweetpotato

Acknowledgement
• SIDA/Bioinnovate program -Financial support
• KARI- Administrative and technical support
• Collaborators/partners