Progress and Achievements in the Genetic Enhancement and Breeding of Cassava for Sub-Saharan Africa
-
Upload
international-institute-of-tropical-agriculture -
Category
Technology
-
view
816 -
download
8
description
Transcript of Progress and Achievements in the Genetic Enhancement and Breeding of Cassava for Sub-Saharan Africa
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Progress and Achievements in the Genetic
Enhancement and Breeding of Cassava
for Sub-Saharan Africa
2005 -2007
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
• Famine reserve crop
• Rural food staple
• Cash crop for urban consumption
• Industrial raw material
• Earner of foreign exchange
Five main roles
Food and
Beverage
Mono-
sodium
glutamate
Ethanol
Animal
Feed
Paper
Textile
CASSAVA
Oil
drilling
Wood
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Major constraints/traits addressed:
Biotic: Cassava mosaic disease (strains & variants), Cassava
brown streak disease, bacterial blight, root rots,
anthracnose disease, green mite and root and tuber scale.
Abiotic: Soil acidity, soil fertility, drought.
Nutritional: Root dry matter/starch content, mealiness (cooking quality),
cyanide content, and beta-carotene and protein contents.
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Others:
Postharvest physiological deterioration (PPD).
New Opportunities:
• Industrial and diversified uses (e.g. high root starch content,
starch quality such as waxy starch, and high sugar content for
bio-ethanol production)
• Livestock feed (e.g. high root and foliage yield and protein
content).
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
1. High root dry matter and starch yield (per unit area and time)
2. Improved quality and nutrition (e.g., high starch content and quality,
low cyanogenic potential (CNP), mealiness, reduced or delayed
postharvest deterioration, high beta-carotene content, high protein
content, foliage yield, and quality)
3. Disease resistance (CMD, CBSD, CBB, CAD, root rots)
4. Pest resistance (CGM, ARTS, and whiteflies)
5. Good plant type
6. Good adaptation to major agroeecologies and production systems
Breeding objectives for the development of
new cassava varieties in SSA
Geographical Focus
Humid forest, moist savanna, dry savanna and midaltitude
agroecological zones.
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
NARS
• 19 NARS in West and Central Africa
• *EARRNET (9 NARS in East Africa)
• SARRNET (12 NARS in Southern Africa)
• EMBRAPA and IAC in Brazil.
• *DR Congo and Tanzania common to both EARRNET and SARRNET
Major Linkages
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
ARIS:
University of Copenhagen, German Collection of Microorganisms and Cell
Cultures (DSMZ), Plant Virus Division, Braunschweig, Germany),
Ohio State University
Donald Danforth Plant Science Center (Mo)
Swiss Federal Institute of Technology, Zurich (ETH),
Joint FAO/IAEA Agriculture and Biotechnology Laboratory of the
International Atomic Energy Agency, Austria
HarvestPlus Challenge Program (Consortium of universities and research
institutions worldwide)
BioCassava Plus of the Grand Challenges in Global Health initiative
(Consortium of universities and research institutions worldwide)
Generation Challenge Program (Consortium of universities and research
institutions worldwide).
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Development and improvement of cassava source populations
Basic Strategy of Cyclical Selection of Source Population
Develop a Source Population
Inter-cross
Superior Progeny
Evaluate
Progeny
Select Superior Progeny
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Ploidy Manipulation
Unilateral and Bilateral Sexual Polyploidization
(2x X 2x, 2x X 4x, 4x X 2x, 4x X 4x crosses)
Somatic Polyploidization
Colchicine (0.1%) Sol’nSexual
Diploids (2x)
Somatic
Tetraploids (4x)
Improved Tetraploids
(4x)
Improved Diploids
(2x)
X
Productive Triploids
(3x)
X
Sexual
Tetraploids (4x)
Unilateral and Bilateral Sexual Polyploidization
(2x X 2x, 2x X 4x, 4x X 2x, 4x X 4x crosses)
Somatic Polyploidization
Colchicine (0.1%) Sol’nSexual
Diploids (2x)
Somatic
Tetraploids (4x)
Improved Tetraploids
(4x)
Improved Diploids
(2x)
X
Productive Triploids
(3x)
X
Sexual
Tetraploids (4x)
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
CIAT (2003): 38 clones [Latin American landraces (Brazil, Colombia, and Peru),
South-east Asian landraces (Thailand) targeting whitefly resistance, high starch
content, good eating quality, and agroecological adaptation to the lowland humid,
acid savanna, and midaltitude agroecologies.
Agronomic Institute of Campinas, Sao Paulo, Brazil, Brazil (2005): Industrial
varieties of six elite lines and landraces (high starch and cold tolerant) including
yellow-fleshed lines (IAC 576-70, IAC-12,IAC-14, FECULA-3, ESPETO-7, and
BRANCA DE SANTA CATARINA).
2006: Five (IAC 13, IAC 90, IAC 15, Fecula Branca, Fibra, and Olho Junto).
CIAT (2007): half-sib seeds from the backcross generation of the cultivated
cassava x Manihot walkerae for delayed onset of postharvest physiological
deterioration
Latin Amerian lines (breeding lines and land races) with higher storage root
protein and yellow fleshed roots
Five genotypes and 50 tissue culture derived plantlet from seeds of the first
backross generation of selected interspecific progenies for high protein.
Swiss Federal Institute of Technology, Zurich (2007): Some cassava lines for high
starch content from Asia (KU50, MThai 25 and MThai 27).
Germplasm Introduction (further broaden the genetic base)
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Acquisition of micronutrient rich (beta carotene) seed
populations
CIAT 2005: = 207 families (4754 seeds)
EMBRAPA, Brazil (through CIAT) 2005: Micronutrient rich
(betacarotene)=59 families (8074 seeds)
Tanzania Landraces and improved varieties 18
Malawi Landraces and improved varieties 14
Zambia Landraces and improved varieties 11
Acquisition of African adapted germplasm
(2004)
• Evaluation, introgression into breeding pools and selection
42 African varieties were introduced from South Africa as virus-
tested in vitro plantlets in 2004 to enrich IITA breeding population
with African adapted gene pools
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Mosaic Disease Bacterial Blight Root RotsAnthracnose
Green MiteMealybug African Root and Tuber Scale
Major Disease/Pest Constraints of Cassava
Brown Streak Disease
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
CMD-resistant CMD-susceptible Multiple resistance to diseases and pests
Improved multiple disease and pest resistant clones showing high levels of resistance to CMD
While incorporating resistance to diseases and pests, popular features of African landraces are maintained to aid adoption
Host-plant Resistance Breeding
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Variety FWS DWF Rel. imp
TME 419 12.14 3.58 27.40
92/0326 15.14 3.63 29.18
97/4779 14.66 3.7 31.67
92/0057 18.78 3.82 35.94
98/0581 16.4 4.13 46.98
M98/0040 15.09 5.18 84.34
99/6012 15 8.51 202.85
30572 16.41 2.46 0.00
4(2)1425 13.63 2.27 0.00
82/00058 18.47 3.71 0.00
96/1632 14.93 0.88 -68.68
98/2226 15.47 1.13 -59.79
97/0211 9.51 1.48 -47.33
96/1569 7.21 1.68 -40.21
97/3200 14.63 1.74 -38.08
99/2123 19.36 1.77 -37.01
99/3073 16.46 1.77 -37.01
Mean 15.26 2.74
CV 18 45
SE 0.42 0.19
Relative
improvement in
forage yield of
improved varieties
over the checks
FWS = Fresh weight shoot (t/ha); DWF = Dry weight forage (t/ha); Rel. imp = Relative improvement
based on DWF (%)
• Among the 43 tested clones seven
produced more forage compared to the
control
• They include clones 99/6012 (203%),
M98/0040 (84%), 98/0581 (47%), 92/0057
(36%), 97/4779 (32%), 92/0326 (29%) and
TME 419 (27%)
• Cassava clone 99/6012 gave an
outstanding performance producing more
than thrice the forage yield obtainable in
the three checks
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
β-carotene 6 & 9 MAP DF =24 T value = -7.96 p <.0001
β-carotene 6 & 12 MAP DF =24 T value = -7.34 p <.0001
β-carotene 9 & 12 MAP DF =24 T value = 2.53 p = .0182
Iron 9 & 12 MAP DF =24 T value = 5.24 p <.0001
Zinc 9 & 12 MAP DF =24 T value = 2.68 p =.0132
Mean concentration of micronutrient
@ 6, 9, &12MAP
β-carotene (μg/g) Iron
(mg/kg)
Zinc (mg/kg)
MAP 6 9 12 9 12 9 12
Mean 0.33 3.08 2.09 9.36 6.52 9.04 7.93
SE 0.25 0.88 0.65 0.8 0.78 0.57 0.54
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Year Total
No.
families
Total
No.
plants
Screening method Deep
yellow
selected
Light
yellow
selected
Min
TC
Max
TC
2004/05 476 16,832 Color chart,
spectrophotometric
24 379 - 10.1
μg/g †
2005/06 982* 19,644 Color chart,
spectrophotometric
895 1386 2.8
μg/g
11.9
μg/g
2006/07 490 8743 Color chart,
spectrophotometric
667 158 1.23
μg/g
14.81
μg/g
2007/08 638 28,865 Color chart,
spectrophotometric
1548 >500 1.56 13.27
*Comprised of 133 families from CIAT, 59 from Brazil, and 790 local crosses from IITA Ibadan ; †obtainedfrom 2005 clonal evaluation.
Screening for Carotenoids, Fe & Zn
Carotenoids (fresh wt basis)
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Year No.
families
No.
plants
Screening
method
Max
Fe
Max
Zn
2004/05 476 16,832 - - -
2005/06 982 19,644 ICPAES - -
2006/07 490 8743 ICPAES 56.81
mg/kg
73.78
mg/kg
2007/08 638 28,865 ICPAES
Fe and Zn (dry wt basis)
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
GLM :
G x E interactions
components for Fe
& Zn generally ns
AMMI:
•High G –TC
•High E & G x E–
Zn, Fe
•G (Fe) ~ G( Zn)
G x E
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
G x E: carotenoid concentration
Carotenoid
concentration is
a stable trait
Single location
selection reliable
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Agronomic characteristics, pest reactions of
promising micronutrient-rich clones
Clone CMD CGM Yield DM Carotene Fe Zn
(t/ha) (%) (µg/g) mg/kg mg/kg
05/1601 1.0 2.0 36.5 38.9 9.4 10.7 12.2
05/1600 3.2 2.5 34.5 29.0 6.5 9.0 12.0
05/1570 1.0 2.0 33.3 41.9 2.4 7.9 12.3
05/0327 1.0 4.5 28.4 37.8 6.2 6.5 14.3
05/1862 1.2 2.5 27.1 39.3 4.5 7.7 10.3
05/0311 1.0 2.5 25.7 40.9 5.5 7.2 8.3
05/0099 1.0 2.0 25.1 38.9 5.8 7.0 8.9
05/1654 1.0 3.0 23.0 34.9 6.9 17.4 15.1
05/0476 1.0 3.0 19.7 40.3 4.0 8.9 10.5
05/1652 1.0 2.5 19.5 31.3 8.3 9.4 13.8
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
G effect highest for DM
E effect highest for YLD
G x E*** for all traits
G x E: YLD, DM, DY
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Percentage nutrient retention during traditional
processing of yellow-fleshed cassava storage roots
Highest nutrient retention in boiled rootsMaziya-Dixon et. al., 2007.
Submitted to LWT-J. Food Science
0
20
40
60
80
100
120
Sun-dried
chips
Raw fufu Cooked
fufu
Boiled
cassava
gari
Processed product
Pe
rc
en
t tr
ue
re
ten
tio
n
01/1371
01/1235
94/0006
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Maziya-Dixon et al., 2007. Int. J. Food Science and Technology.
Carotenoid concentration at different steps of
processing cassava storage roots to gari
0
2
4
6
8
10
12
14
16
18
Peeled raw
cassava
roots
Grated
cassava
mash
Grated and
fermented
mash
Fermented
pressed
mash/cake
Roasted gari
granules
To
tal caro
ten
oid
(u
g/g
)
TMS94/0006
TMS01/1235
TMS01/1371
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Carotenoids profile of 22 yellow-fleshed
cassava genotypes
90% of the carotenoids in cassava is β-carotene
> 50% of the carotenoids in cassava is Trans- β-carotene
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Tetraploidy was also artificially
induced (0.1% solution of
cholchicine) in over 20 promising
yellow-fleshed diploid cassava
clones.
4x versus 2x counterparts
Effect of polyploidization on
micronutrient content evaluated
(carotene 4x>carotene2x)
Tetraploid x diploid crosses for
more productive triploids
Polyploid breeding for enhanced
micronutrient content
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Tetraploids (mean = 5.41 µg/g) had significantly higher content of total carotene
than the diploids (mean=4.65 µg/g).
The carotene content of the tetraploids ranged from 0.69 µg/g to 10.05 µg/g; that of
the diploids ranged from 0.44 to 8.39 µg/g.
The mean dry matter content of the tetraploids (33.45%) was significantly lower
than that of the diploids (36.78%), though several of the tetraploid clones had higher
dry matter content of over 36%.
The dry matter content of the diploids ranged from 27.19% to 42.49%; that of the
tetraploids ranged from 27.82% to 37.91%.
The clone x ploidy level interaction for both total carotenoid and dry matter content
was also significant.
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Descriptive statistics for chemical composition of cassava leaves
(DWB) of 630 genotypes
Total
sugars
(%)
Starch
(%)
Protein
(%)
Dry
Matter (%)
Fat
(%)
Tannin
(mg/100g)
Mean 8.49 16.17 30.12 26.37 6.05 8.85
SE 0.16 0.17 0.08 0.11 0.04 0.08
Min. 2.4 4.0 25.6 18.0 1.3 4.0
Max. 62.8 35.3 38.0 53.0 14.9 17.2
Pr. > F ns ns *** ** ns ns
* * *, * *, *Significant at P<=0.001, P<=0.01, and P<=0.05 respectively; ns=not significant
P>=0.05
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Descriptive statistics for chemical composition of cassava storage roots
(DWB) of 637 genotypes
CNP1 Total
sugars
(%)
Starch
(%)
Protein
(%)
Ash
(%)
Amylose
(%)
Dry
matter
(%)
Mean 14.6 5.83 60.49 2.26 3.65 19.41 24.81
SE 0.26 0.11 0.37 0.02 0.03 0.08 0.17
Min. 3.9 0.6 20.1 0.7 2.1 11.6 11.1
Max. 39.0. 20.0 93.0 4.8 6.1 29.2 42.8
Pr. > F * * * ns ns * * * * * * * * * ** * *, * *, *Significant at P<=0.001, P<=0.01, and P<=0.05 respectively; ns=not
significant P>=0.05; 1= mg/100 g HCN Equivalent
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Descriptive statistics for functional (pasting) characteristics of cassava
storage roots of 637 genotypes
Peak
viscosity
Breakdown
viscosity
Final
viscosity
Setback
viscosity
Peak time
(Min.)
Pasting
temp.( C)
Mean 196 115 112 32 4.63 82
SE 2.22 1.45 2.14 0.69 0.02 0.62
Min. 52 26 2.5 0.2 1.9 50
Max. 633 479 265 106 7.0 89
Pr. > F * * * * ns ns ns ns
* * *, *Significant at P<=0.001, and at P<=0.05 respectively; ns=not significant
P>=0.05
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
What we learnedThere is a relationship between physical, chemical, and functional characteristics of the raw material and the final product, therefore we need to target our technologies
Processing resulted in reduction of provitamin A carotenoid retention and that this depended on the genotype and processing method.
There is a potential for improving micronutrient status of vulnerable groups
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
2003/2004 2006/2007 % increase
β-carotene 4.8μg/g 13μg/g >150
Iron 10.3mg/kg >35mg/kg >200
Zinc 10.3mg/kg > 60mg/kg >400
Protein 1-4% >25% >400
Shift in nutrient levels with breeding and
selection for root nutritional quality
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Virus-free certified tissue culture plantlets
Deployment of in vitro germplasm
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Country Seed families No. of seeds
Guinea 71 10,100
Congo DR 30 10,000
Uganda 64 10,100
Kenya 23 23,000
Malawi 24 24,000
Angola 23 23,000
Mozambique 23 23,000
Sierra Leone 23 46,000
Ghana 17 18,100
HS seed families of beta-caroten enriched parental
clones
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Some official varietal releases of improved cassava by
NARS between 2004 and 2007
Year Country Variety name
2004 DR Congo TMS 95/0211 (Disanka), TMS 95/0528 (Mvuazi), TMS 96/0160
(Nsansi), MV 99/0395 (Butamu), MV 99/0038 (Zizila), MM
96/0287(Liyayi), and MM 96/7204 (Namale)
2004 Swaziland Clones 160, 48 & 65, TMS 92/0326, and Rushinga
2005 Ghana: TMS 97/4962 (Abglifa), TMS 97/4414 (Bankyehemaa), TMS
97/3982 (Esam bankye), and TMS 97/4489 (Doku duade)
2005 Nigeria TMS 97/2205, TMS 98/0505, TMS 98/0510, TMS 98/0581, and
TME 419.
2006 Nigeria TMS 92/0326, TMS 92/0057, TMS 96/1632, TMS 98/0002, and NR
87184.
2006 Sierra Leone TMS 92/0057 (SLICASS 6)
2007 Benin TMS 91/02322 (Manina), TMS 92B/00061(Ina–H), TMS
92/0427(Ina – Premier), and TMS 92/0067 (MR-67)
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
IITA No DRC name CMD Yield (t/ha)
96/0160 Nsansi 1 22.8
95/0528 Mvuazi 1 21.6
MV99/0038 Zizila 1 21.5
95/0211 Disanka 1 20.7
MV99/0395 Butamu 1 16.8
RAV RAV 3 18.6
Boma Boma 4 9.46
Nouvelles variétés en diffusion
CMD score of 1-5 where 1=no symptoms and 5 =severe damage
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Degree and non-degree training
Training of Trainers
Demand-driven processing workshops
Capacity building and technology dissemination
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Seven additional sources of resistance to CMD and other prelent disease and
pest identified in landraces collected from West Africa and used to pyramid and
diversify and heighten resistance for durable control.
Significant advances in broadening the genetic base of cassava in Africa
and producing several improved cassava genetic stocks and breeding
materials which combines enhanced CMD resistance with improved post
harvest qualities, multiple pest/disease resistance, wide agrocological
adaptation and greatly improved yield potential (which may also be used
directly as varieties) and shared with NARS.
Massive use of African landraces and Latin America germplasm
(increased yields in many African locations by 50-100% even without the
use of fertilizer).
Summary of the progress and
achievements
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
In vitro virus-tested plantlets and seed populations of broad-based and special
trait source breeding populations exchanged with National programs
Increasing number of improved varieties released by NARS in major cassava
producing countries of the cassava belt as a result of broadening the genetic base
of cassava at IITA with Latin American germplasm and the increased use of
African landraces in the breeding program.
Enhanced NARS research capacity in cassava through training under IITA co-
supervision for MSc, PhD, and/or group training, and extensive collaboration
throughout SSA.
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Minister of Agriculture and senior officials of FMARD–IITA (10 Feb)
Public Awareness and Advocacy
Dignitaries at the high table during the
book launchVP, FGN on a visit to IITA
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Key challenges
• Planting materials
• Labour
• Germplasm
• Soil fertility
• Diseases and pests (including weeds)
• Post-harvest handling and processing
Yam Genetic
Improvement
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
High and stable yield of marketable tubers
(per unit of area, labour and time)
Pest and disease resistance
(nematodes, viruses, anthracnose, tuber rots)
Tuber characteristics(size, shape, branching, food quality, storability)
Suitability to cropping systems and tolerance to
abiotic stresses
(shoot morphology, nutrient responsiveness and
use efficiency, tolerance to mid- to late season
drought)
Genetic
Improvement
Objectives
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Dioscorea rotundata
D. alata
D. cayenensis
D. dumetorum D. burkilliana
D. bulbifera D. esculenta
D. opposita D. japonica
D. trifida D. nummularia
D. abyssinica D. praehensilis
Focus on
Selected Food
Yams
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
•Whole tuber
•Tuber fragment
•Milking (double harvest)
•Multiple tuberisation
•Bulbil formation
Planting Materials
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Staking in forest zone
Mounds for ceremonial yam Mounds in savanna zone
Staking in savanna zone
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Good performance under no/limited staking
Early maturity and/or multiple tuber production
Suitability to short fallow systems
-Nutrient uptake, responsiveness & use
efficiency
-Pest resistance
Tuber morphology for easy harvesting
Long tuber dormancy
Labour Saving
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Anthracnose disease
Sources of resistance identified to selected isolates and
used but variability of pathogen is a continuing challenge
Abang et al. 2006. Journal of Phytopathology 154: 51-61
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Sources of resistance identified and hybridized
Odu et al. 2006. Journal of Phytopathology 154: 716-724
Odu et al. 2006. Journal of Phytopathology 154: 688-693
Odu et al. 2004. Field Crops Research 89: 97-105.
Odu et al. 2004. Plant Pathology 53: 141-147
Viruses
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Country Partner No. of clones
Benin INRAB 234
Cote d’Ivoire CSRS 80
Ghana CRI & WASDU 169
Nigeria NRCRI 104
Togo ITRA 166
Example of delivery of new clones of D.
rotundata to partners in a year
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
National Root Crops Research Institute, Nigeria:
Three new varieties of D. rotundata in 2001
Four new varieties of D. rotundata in 2003
Crops Research Institute, Ghana:
Three new varieties of D. rotundata in 2005
Varietal
releases
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Nematodes
Necrotic spotsCracks & flaking of skin Dry rot
Damage caused by Scutellonema bradys
Galls & crazy rootsGalls
Damage caused by Meloidogyne spp.
Galls and rot
Resistance
identified in
Dioscorea
dumetorum
but not in
the two
dominant
species –
D. alata
and D.
rotundata
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Insect pests of yam tubers
MealybugsScale insects
Tuber moth damageYam beetles
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Internal Brown Spot
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Opportunities
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Colonization (%) of roots of Dioscorea alata by VAM fungi at 4 sites
in Nigeria
Clone Site
Abuja Ibadan Onne Ubiaja Mean
TDa 85/00250 68.00 84.72 39.94 88.32 70.25
TDa 00/00064 78.23 45.09 61.06 88.84 68.31
TDa 00/00104 75.55 55.58 51.98 89.23 68.09
TDa 92-2 72.90 20.91 34.65 75.77 51.06
TDa 99/00395 44.49 45.69 34.78 77.29 50.56
TDa 02/00193 58.97 35.78 48.64 54.64 49.51
TDa 93-36 50.54 28.47 32.48 82.38 48.47
Mean (36 clones) 68.64 45.15 44.31 78.20 59.08
S.e.d: clone = 6.3, location = 2.1, clone x location = 12.6
CV% = 26.1
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Colonization (%) of roots of Dioscorea rotundata at 4 sites in Nigeria
Clone Site
Abuja Ibadan Onne Ubiaja Mean
TDr 97/00588 85.42 78.89 58.38 81.23 75.98
TDr 89/02665 79.38 44.53 78.01 71.50 68.36
TDr 96/01799 79.03 47.67 77.33 69.00 68.26
TDr 96/00528 53.73 49.57 52.90 31.25 46.86
TDr 97/00903 62.38 47.53 1.12 69.78 45.20
TDr 97/00632 56.73 31.45 51.37 40.47 45.01
EHOBIA 33.18 30.53 28.83 44.25 34.20
Mean (for 34 clones) 67.99 43.04 57.11 59.73 56.97
S.e.d: clones = 6.54; Location = 2.24; Clone x location = 13.07
CV (%) = 28.1
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Screening for tuber contents of total carotenoids, iron, zinc, ascorbic acid, and phytic acid
Variation in retention of total carotenoids, Fe and Zn in Dioscorea cayenensis food products
Influence of environment and genotype x environment interactions on tuber contents of iron and zinc
Total carotenoids (in µg/g fwb)
Dioscorea cayenensis (82 accessions)
Range: 1.25 – 5.12
Mean: 2.72 + 0.80
D. dumetorum
Two accessions with values of 22.29 and 26.60 µg/g
Tuber Density of
Micronutrients
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Tuber content of ascorbic acid (in mg/100g fwb) :
D. rotundata (325 accessions)
Range: 3.56 – 16.87
Mean: 8.3 + 2.26
D. cayenensis (79 accessions)
Range: 4.19 – 11.34
Mean: 7.85 + 1.29
D. dumetorum (31 accessions)
Range: 15.42 – 39.43
Mean: 25.83 + 6.29
Tuber Density of
Micronutrients
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Iron Zinc Ascorbic acid
SOV DF MS % SS MS % SS MS % SS
Total 371 4.90 3.94 2.46
TRT 123 9.74*** 65.8 9.02*** 75.8 4.76*** 64.2
GEN 30 13.76*** 34.4 23.08***62.4 5.68*** 29.2
ENV 3 115.94***29.0 45.60***12.3 61.40*** 31.5
G x E 90 4.86*** 36.5 3.10*** 25.2 2.56*** 39.4
Tuber nutrient contents of 31 genotypes of D. rotundata evaluated
at 4 sites over two years in Nigeria
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Retention (%) of micronutrients in products from
15 genotypes of Dioscorea cayenensis
Boiled yam Pounded yam Flour
Carot. 31-97 9-97 11-75
(69.6) (48.6) (43.2)
Iron 56-99 66-99 18-44
(77.2) (80.3) (29.4)
Zinc 70-96 62-97 13-32
(85.4) (83.6) (22.6)
Micronutrients
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Descriptive statistics for functional (pasting) characteristics of 33 genotypes
of D. rotundata grown at Abuja, Nigeria
Peak
viscosity
Breakdown
viscosity
Final
viscosity
Setback
viscosity
Peak time
(Min.)
Pasting
temp.( C)
Mean 209 38 247 76 6 84
SE 11.7 6.6 12.86 7.66 0.11 0.17
Min. 69 4 97 29 5 82
Max. 338 147 397 209 7 86
Pr. > F ** * * * * * * * ns
* *, *Significant at P<=0.01, and at P=0.05 respectively; ns=not significant
P>=0.05
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
0.00
50.00
100.00
150.00
200.00
250.00
300.00
350.00
Pea
k Visc.
Troug
h
Breakd
own
Final visc.
Setba
ck
Pas
ting tim
e
Pas
ting temp.
D. alata
D. rotundata
Evaluation of Dioscorea alata varieties for
making pounded yam
Mean pasting
properties of D.
alata and control
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Mean scores for pounded yam from D. alata
Variety Color Smoo. Cons. Elast. Stick. Hard.
Mean 4.66 4.22 3.97 3.56 4.22 4.66
SE 0.27 0.11 0.14 0.14 0.14 0.12
P level *** *** *** ** ** ***
Scale of 1 to 9, where 1= extremely inferior, 2= much inferior, 3= moderately
inferior, 4 = slightly inferior, 5= no difference, 6= slightly better, 7=moderately
better, 8=much better, 9= extremely better
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
Benin
Institut National des Recherches Agricoles du Benin (INRAB)
Centre régional de Nutrition et d’Alimentation Appliquées (CERNA)
Cameroon
University of Dschang
Institute of Agricultural Research for Development (IRAD)
The University of Buea
AGROCOM
Cote d’Ivoire
Centre National de Recherche Agronomique (CNRA)
Centre Suisse de Recherches Scientifiques en Côte d’Ivoire (CSRS)
University of Abobo Adjame
Ghana
Crops Research Institute (CRI)
Savanna Agric. Research Institute (SARI)
Kwame Nkrumah University of Science and Technology (KNUST)
University For Development Studies
Nigeria
National Root Crops Research Institute (NRCRI)
Bowen University
Ladoke Akintola University of Technology (LAUTECH)
Togo
Institut Togolais des Recherches Agronomiques (ITRA)
Key NARS
Partners
International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
• CIRAD, France
• Virginia State University, USA
• University of Ibadan, Nigeria
• Federal University of Technology, Nigeria
• Ahmadu Bello University, Zaria, Nigeria
• University of Nigeria, Nigeria
• Ladoke Akintola University of Technology, Nigeria
Graduate Training 2007
• 10 students conducting research towards PhD degrees
Other Research
Partners