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Presentation # S16-001; 20 January 2016, World Congress on Root and Tuber Crops, Nanning, China
The YIIFSWA protocol for enhancing seed yam quality and fostering seed yam certification in West Africa
Lava Kumar
International Institute of Tropical Agriculture (IITA)
N Maroya (IITA), B. Aighewi (IITA), E.J. Zidafamor (NASC), S.A. Adzivor (PPRSD),
E. Boateng (CRI), F.A. Oppong (CRI), I. Kalu (NRCRI), I. Ikoro (NRCRI), S. Alhassan (SARI), P.A. Danquah (GLDB), E.A. Asamoh (GLDB) and D. Coyne (IITA)
1. Seed yam production in West Africa and
YIIFSWA purpose
2. Technologies for quality seed production
3. Review of seed yam certification standards
4. Revised seed yam quality management
protocol
Outline
Yam (Dioscorea spp.)
•Multispecies crop propagated using tubers
•D. rotundata > D. alata > D. cayenensis are the dominant species
•92% of the 63 million t of global edible yam production is confined to West Africa
Yam is propagated using seed tubers
Ware yam ~1.5 to 4 kg
Seed yam ~200 to 500 g
Seed yam Ware yam
Vine cuttings
Aeroponics Bioreactors Minisetts
Micro/ minitubers
Co
nve
nti
on
al m
eth
od
s N
ove
l met
ho
ds
Seed yam production
• About 30 to 40% of the harvested yam is used as ‘seed yam’
• Seed yam constitutes 40-50% of the total yam production costs
• Seed yam quality is an important attribute to attain optimum ware yam yield and quality
• Unavailability of quality seed yam has been identified as major constraint to yam production in West Africa
•Pests and diseases are major factors for reduced yield and quality Foliar diseases reduces yields
Mosaic (Yam mosaic virus, Yam mild mosaic virus) Anthracnose (Colletotrichum gloeosporioides)
Infected Healthy
10.3
5
0
2
4
6
8
10
12
Healthy Infected
Kg
Weight of 20 tubers
Pests and diseases are major factors for reduced yield and quality Foliar diseases reduces yields
Mosaic (virus) and anthracnose (fungus) – Tuber diseases affects quality
• Nematodes, insects and rots
Nematodes Beetles Wet rot Mealybugs/scales
Degeneration during storage (~2 months storage for breaking dormancy)
Pests and diseases are major factors for reduced yield and quality
Foliar diseases reduces yields
Mosaic (virus) and anthracnose (fungus)
– Tuber diseases affects quality
• Nematodes, insects and rots
– Pests and diseases affects seed yam health
• Poor germination, poor plant performance and
seed degeneration
-Recycling of contaminated seed
-Farmers save small and poor seed for planting
-Contaminated seed acts as vehicles for spread of pests
and pathogens from generation-to-generation
-Unavailability of ‘clean’ seed yam stocks of popular cultivars
-Most seed stocks of improved and landraces are
contaminated
Virus infection
Nematodes Beetles Scales Mealy bugs Termites Fungi & bacteria
Cat
ego
ry 1
Sorting & Curing (chemical /physical treatment)
Cat
ego
ry 2
Selection & Virus elimination
10.8
0.73
1.38
0.72
0.99
1.07
1.01
1.84
1.3
0.69
1.45
0
5
10
15
20
25
1
Soil
Drought
Weed
Seed
Anth
Vir
Nem
Rot
Var
Agron
Actual
Avg
. cu
rre
nt
yie
ld in
WA
(t/
ha)
t/h
a
seed
Virus Fungi
Nematode •Addressing seed quality can enhance yields by ~4.9 t /ha
• Yam Improvement for Income and Food Security in West Africa (YIIFSWA)
• Nigeria and Ghana (47.6 million t production; represents 75% of the global yam production)
YIIFSWA (funded by BMGF)
Purpose • Develop yam seed systems to ensure availability of
sufficient quantities of pest- and disease-free seed yam on a commercially viable basis capable of increasing yam yields by at least 50%.
• Develop technologies for high ratio propagation of high quality pre-basic, basic and certified seed yams, and also improve the quality of farmer saved seed yam.
• Develop effective technologies for managing the quality of seed yams
Interventions for seed quality
improvement
•High ratio propagation technologies
•Procedures for production of virus-free plants
•Diagnostic tools for virus indexing
•Quality management protocol (certification)
Sensitive & Robust Virus Diagnostic Tools Developed
Type Purpose Stage of development
Multiplex RT-PCR Simultaneous detection
of 3 RNA viruses
Completed
Antibodies for YMV,
YMMV and Badnavirus
ELISA, IC-PCR and
LFD based diagnostics
Completed
RT-LAMP and RPA
(YMV & YMMV)
On-site tool kit Completed
Single tube multiplex PCR RT-LAMP
•Yam mosaic virus, Yam mild mosaic virus and Cucumber mosaic virus
On-site diagnostic tests
•Lateral flow immuno detection test for YMV •LAMP and RPA for YMV and YMMV
Private Seed Sector Exposure Visit 6 August 2015
Production of virus-free planting material
Variety Mini-setts Vines
Adaka 22 122
Aloshi 222 4646
Amola 29 451
Gbangu 82 1133
Obioturugu 42 388
Ogini 401 1691
Tdr 89/02665 42 189
Indexing process
•Minisetts
•Vine propagation
•Aeroponics
•Tissue culture (Bioreactors)
Production
•Field
•Screenhouse
(vine cuttings/aeroponics)
•Lab (tissue culture/bioreactors)
High-ratio seed yam
propagation technologies
•Vine propagation
•Aeroponics
•Tissue culture (bioreactors)
Quality seed production status
•Minisetts
•Free from pests, fungi and viruses (cleanest seed stock)
•Infusion for production of pre-basic seed just begun
• Production of pest and fungi-free seed yam
• Used for pre-basic, basic and certified seed production
ECOWAS Certification Standards for Root and Tuber Plant Seed C/REG.4/05/2008
ECOWAS Standards
National seed certification standards for yam in Nigeria and Ghana
Quality management protocol
•Pre-basic (Breeder seed) •Basic (Foundation seed) •Certified seed (Commercial seed)
Quality management protocol
Storing
Bagging and labelling
Post-harvest sorting (size) and cleaning (soil, treatment)
Harvest
Agronomy (rouging, weeding, staking)
Planting (spacing)
Preparation of seeds (sorting and treatment
Procurement of seeds (authentic source)
Field preparation
•Pre-planting
•Planting
•Post-planting
(field assessment)
•Harvest and storage
Quality management protocol Ex-ante assessment
• Rarely used in Nigeria or Ghana
• Breeder seed: produced by breeders
• Foundation and certified seed: produced by registered seed users
• Both released varieties and landraces certified
• Limited capacity for field certification
• Challenges in decision making based on the ‘specified standards’
ECOWAS NIGERIA GHANA BREEDER & FOUNDATION: Anthracnose, 0.05%; Stem Mealy Bug, 0%; White Scale Insect, 0.1%; Target spot , 0.05%; Nematodes, 0.05%, Viral Diseases, 0%. CERTIFIED: Anthracnose, 0.01%; Stem Mealy Bug, 0%; White Scale Insect, 1%; Angular Leaf, 0.1%; Nematodes, 1%, Viral Diseases, 0%.
BREEDER & FOUNDATION: Anthracnose, 0.05%; Stem Mealy Bug, 0%; White Scale Insect, 0%; Nematodes, 0%, Viral Diseases, 0%. CERTIFIED: Anthracnose, 0.1%; Stem Mealy Bug, 0%; White Scale Insect, 0%; Nematodes, 0%, Viral Diseases, 0%.
BREEDER & FOUNDATION: Anthracnose, 0.1%; Stem Mealy Bug, 0%; White Scale Insect, 0%; Nematodes, 0%, Viral Diseases, 0% CERTIFIED: Anthracnose, 0.5%; Stem Mealy Bug, 0%; White Scale Insect, 0%; Nematodes, 0%, Viral Diseases, 0%.
Standards for pest and diseases
• Pest and disease situation in Nigeria and Ghana
• Surveys in 3 seasons (2012-14); 40 locations in each country
Mean incidence and prevalence in
Nigeria and Ghana (baseline)
Threat Incidence Prevalence
Viral disease 85% 90%
Nematodes 25% 89%
Anthracnose 25% 72%
Insects 15% 75%
Tuber rot 8% 36%
10 Farms per state; 8 states in Nigeria 20 freshly harvested tubers assessed per field
Total 1580 tubers
•Percent occurrence of various pests and damage to yam tubers in Nigeria
0
5
10
15
20
DRY ROT CRACKTUBER
GALLTUBER
CRAZYROOT
MEALYBUG
WET ROT TERMITE
% incid
ence
•Current standards are too stringent for application
•Pre-basic seed •Basic seed •Certificated seed
•Procedures to ensure healthy (free from
pests and pathogens), true-to-type and
quality (physical attributes).
Revised Seed Yam Quality Standards
STANDARDS PARAMETERS ECOWAS
CURRENT SITUATION RECOMMENDED TOOLS NIGERIA GHANA
REGISTRATION OF SEED PRODUCERS YES YES YES
Accept ECOWAS standards
Growers' Registration
Form
EVIDENCE OF SEED SOURCE YES YES YES
1. Receipt of Purchase/ Delivery
Note; 2. Certification Tags; 3. Branded
Packaging Material.
Make available any of the three
evidences
SITE SELECTION YES YES YES Suitable Soil for Seed
Yam Production
Mobile Soil Testing
Equipment; Well Equipped Lab
CROPPING HISTORY
FIELD SHOULD NOT CARRY YAM FOR AT
LEAST ONE YEAR YES YES
Advocate crop rotation (Cereals/
Legumes) Farmers' Log
Book ISOLATION DISTANCE 5 M 5 M 10 M 3 M
GPS; Measuring Tape
OFF TYPES*
0.05% FOR BREEDER &
FOUNDATION, CERTIFIED 0.1%
0.05% FOR BREEDER & FOUNDATION;
1.10% FOR CERTIFIED SEED YAM
0.1% B & F; 0.2% for Certified
Breeder and Foundation Seed Yam: 0.05%; Certified Seed
Yam: 0.2% Cultivar
descriptors
Standards for Pests and Diseases (Maximum tolerance)
Existing Standards Yam QMP** ECOWAS* NIGERIA* GHANA*
Pre-basic & Basic
seed
Anthracnose, 0.05%
Mealybug, 0%
Scale Insect, 0.1%
Target spot , 0.05%
Nematodes, 0.05%
Viral diseases, 0%
Certified seed
Anthracnose, 0.01%
Mealybug, 0%
Scale Insect, 1%
Target spot , 0.1%
Nematodes, 1%,
Viral diseases, 0%
Pre-basic & Basic
seed
Anthracnose, 0.05%
Mealybug, 0%
Scale Insect, 0%
Target spot , 0%
Nematodes, 0%
Viral diseases, 0%
Certified Seed:
Anthracnose, 0.1%
Mealybug, 0%
Scale Insect, 0%
Nematodes, 0%
Viral diseases, 0%
Pre-basic & Basic
seed
Anthracnose, 0.1%
Mealybug, 0%
Scale Insect, 0%
Target spot , 0%
Nematodes, 0%
Viral diseases, 0%
Certified Seed:
Anthracnose, 0.5%
Mealybug, 0%
Scale Insect, 0%
Nematodes, 0%,
Viral diseases, 0%.
Pre-basic & Basic seed
Anthracnose, 10%
Mealybug, 10%
Scale Insect, 10%
Target spot, 10%
Nematodes, 10%
Viral diseases, 10%
Certified Seed
Anthracnose, 20%
Mealybug, 20%
Scale Insect, 20%
Nematodes, 20%
Target spot , 20%
Viral diseases, 20% *Values are incidence in current standards
**Values are incidence of plants exceeding severity point score
This values will gradually revised towards high stringency.
STANDARDS PARAMETERS ECOWAS
CURRENT SITUATION RECOMMENDED TOOLS NIGERIA GHANA
NUMBER OF INSPECTIONS 3 3 4 Minimum of 3
STAGES OF INSPECTION
AT 90 DAP; 150 DAP & 200 DAP
AT 90 DAP; 150 DAP & 200 DAP
PRE-PLANTING; 90 DAP; 150 DAP & 200
DAP
PRE-PLANTING; VEGETATIVE: 120 DAP
+/- 14 DAYS; POST-HARVEST
Cultivar descriptor
INSPECTION PATTERN NONE NONE NONE
Sampling Block of 5 M x 20 M (Subject to
Review) GPS; Measuring
Tape
CERTIFICATION NONE NONE NONE
1. Issuance of Certificate; 2.
Packaging in Net Bags/ Jute Sacks with
Certification Tags. Field Standard
Manual
STANDARDS PARAMETERS ECOWAS
CURRENT SITUATION RECOMMENDED TOOLS NIGERIA GHANA
NUMBER OF PLANTS TO BE EVALUATED PER HA NONE NONE NONE
4 Sampling Blocks of 5 M x 20 M with a
minimum of 50 plants per Block
GPS; Measuring Tape
WEIGHT OF SEED TUBER
BREEDER & FOUNDATION: 150g-
300g; CERTIFIED: 200g-400g
FOUNDATION: 100g-150g; CERTIFIED:
100g-150g
FOUNDATION: 100g-300g; CERTIFIED:
100g-300g
BREEDER & FOUNDATION: 150g-
300g; CERTIFIED: 200g-400g Mobile Scale
TUBERS NOT CONFORMING TO SPECIFIC SIZE OR WEIGHT
BREEDER & FOUNDATION: MAX, 5%; CERTIFIED: MAX,
5%
BREEDER & FOUNDATION: MAX,
5%; CERTIFIED: MAX, 5%
BREEDER & FOUNDATION: MAX, 5%; CERTIFIED: MAX,
5%
BREEDER & FOUNDATION: MAX, 5%; CERTIFIED: MAX,
5% Visual
CUT, BRUISED OR UNSHAPED
BREEDER & FOUNDATION: MAX, 1%; CERTIFIED: MAX,
1%
BREEDER & FOUNDATION: MAX,
1%; CERTIFIED: MAX, 1%
BREEDER & FOUNDATION: MAX, 1%; CERTIFIED: MAX,
1%
BREEDER & FOUNDATION: MAX, 1%; CERTIFIED: MAX,
1% Visual BAGGING AND LABELING NONE NONE NONE
25 Kg Weight in Nylon Net Bags, Labelled in
side and outside
Nylon Net Bags; Certification Tags
and Labels
Training Workshop on QMP to national seed certification authorities
Conclusions
• First example of using ‘severity’ based criteria for
pest thresholds in seed certification
• Revised QMP is practicable way to improve quality
seed yam production under ‘regulatory’ supervision
• Pest and disease standards needs to be revised
every 2 - 3 years, accounting the changes in seed
systems
Thanks for your attention
