1. High Yield Cassava Varieties for Targeted Products and Prospect
Peter Kulakow, Elizabeth Parkes, Ismail Rabbi, Tahirou Abdoulaye, Chiedozie Egesi, Paul Ilona, Alfred Dixon
GCP21 Integrated System for Cassava Production in Africa
28 October 2016
Contact:

2. Overview Cassava breeding objectives
Cassava varieties released in Nigeria
Adoption of Improved varieties
New rapid multiplication system -- SAH
Tools to increase genetic gains

3. Cassava Markets in Nigeria
Boil and eat – fresh consumption
Gari
Other Food Products (fufu, lafun and others)
Industry
1 Source: Context Network analysis based on field research, farmer interviews, and published source analysis
2 Garri: “CTA Presentation”, October 2014
3 Industrial and Other Processed Food: “Sahel Rapid Appraisal of Nigerian Markets for Cassava”, August 2013

4. Current Priority Cassava Breeding Objectives
Yield
High yield of 20 t/ha under stress conditions and 60 t/ha in excellent conditions
Dry matter content above – 35%
Resistance to Cassava Mosaic Disease and Cassava Brown Streak Disease
Resistance to Cassava Bacterial Blight
Drought tolerance
Quality – Regional and Market Specific
White roots – high starch
Yellow roots with at least 15 µg/g fresh weight total carotenoids
Low cyanogenic potential
Poundable year round for boil and eat
Suitable for garri, fufu, starch, flour, chips
White outer skin color

5. Industry Processor Cassava Trait Preference List
Storage root weight 3 to 5 kg/plant
Storage root size
30 – 45 cm long
7 – 13 cm diameter
Straight root
Thin outer skin
White outer skin color
Low cyanogenic potential < 30 ppm
High starch 25 – 30%
Roots do not lose leaves in the dry season –
no drop in starch content at the on set of rains
Maintains starch in the dry season
Disease resistant
Matures in one rainy season
Roots do not become discolored after one season
Straight stems assist mechanized planting
Performs well in different climatic regions
Dry matter content above – 35%
Resistance to Cassava Mosaic Disease and Cassava Brown Streak Disease
Resistance to Cassava Bacterial Blight
Drought tolerance
Quality – Regional and Market Specific
White roots – high starch
Yellow roots with at least 15 µg/g fresh weight total carotenoids
Low cyanogenic potential
Poundable year round for boil and eat
Suitable for garri, fufu, starch, flour, chips

6. Assessment of Gender Responsive Trait Preferences
Household head & spouses trait preference from cassava monitoring study in Nigeria –coded from qualitative question: What characteristics to you want in a cassava variety?
HHs (male)
Overall Key Traits
Freq. %
Rank
high yield
1077
18.05 1
root size
900
15.08 2
early maturity
667
11.18 3
underground storability
420
7.04 4
product quality
400
6.70 5
white pulp
371
6.22 6
low water content
335
5.61 7
mealy
306
5.13 8
taste
219
3.67 9
high stem
196
3.28 10
high starch content
181
3.03 11
product quantity
142
2.38 12
disease and pest resistance
100
1.68 13
yellow pulp 92
1.54 14
ease of peel 80
1.34 15
Spouse (female)
Freq. %
Rank
324
17.57 1
298
16.22 2
230
12.48 3
123
6.72 5 88
4.83 8
132
7.16 4
118
6.44 6 58
3.06 11 38
2.13 14 92
5.04 7 66
3.63 9 39
2.11 22
1.24 16 40
2.18 13 59
3.21 10

7. Focus Group Discussion in 20 Villages
In each study village, the team held one meeting with women, and a simultaneous, separate meeting with men

8. Focus Group Discussion in 20 Villages

9. Focus Group Discussion in 20 Villages

10. Gender Disaggregated Cassava Trait Preferences

11. Officially released varieties
46 Released Cassava Varieties in Nigeria
All are suitable for gari production
6 varieties of biofortified cassava – Vitamin A cassava

12. Best linear unbiased predictors (BLUPS) for 25 released cassava varieties in NIgeria
Early TMS
Varieties
Pre-emptive
Management of
CMD Project
Varieties
Vitamin A
Cassava
Varieties

13. Adoption of improved varieties in Nigeria
Cassava Monitoring Study in Nigeria (IITA, NRCRI)
2500 households in 16 major cassava producing states
Employed DNA fingerprinting to identify each accession by matching them to library of known improved clones and landraces
Sample size:
7411 samples
3891 Reference Library
Total of accessions
Supported by BMGF and RTB

14. Number of samples matching released varieties - regionwise
Predominant adopted varieties were developed prior to 2000
Newer varieties are visible but need greater dissemination through cassava seed systems

15. Potential reasons for low occurrence of new varieties released after 2000
Low availability of planting materials from inadequate seed system
Most common varieties have had massive dissemination investments
Unreliable markets for high yielding varieties discourage adoption
Varieties may lack preferred cassava traits compared to older varieties
Inadequate time for adoption processes for a clonal crop – 30 years versus 10 years

16. Semi-Autotrophic Hydroponics (SAH) Cassava Propagation System
1:2 multiplication in weeks

17. Spread of pests and pathogens through various cassava planting material
Stems
Sterile, virus tested
tissue culture plants
Virus tested
SAH plants
Seed
Insects
+++ -
Bacterial blight +
Fungi (Cassava anthracnose)
Virus (cassava mosaic)
thenationonlineng.net
thenationonlineng.net
A member of CGIAR consortium

18. Breeding cycle for a clonal crop
Low multiplication rate
Long cycle time
Genomic tools can reduce cycle time and increase genetic gain

19. Breakthrough in breeding Vitamin A Cassava
levels of total carotenoids > 20 µg/g fresh weight
To take any decision we go trait by trait. In some cases we can quantify readily. In other cases we need participation of end users.
Best biofortified
Cassava variety
in Nigeria
12 µg/g fr. wt.

20. New populations from Genomic Selection breeding (NextGen Cassava)
Four cycles of genomic selection recombination completed ( )
Field phenotyping of the consecutive cycles ongoing
The first Uniform Yield Trial coming GS project have been established in the current growing season at four locations.
In conventional cassava breeding, new breeding material resulting from a cross is assessed by breeders over several growing seasons and in multiple locations before they select superior clones for the next cycle of germplasm improvement. Cassava is vegetatively propagated, and limited numbers (5-10) of propagules can be obtained from one plant. To obtain sufficient propagules to perform replicated and multi-locational trials for meaningful phenotypic characterization, several cycles of propagation are thus required. Cassava breeding cycles, from seedling to multi-location field trials, can therefore take more than five years, limiting the rate of variety improvement and breeders' ability to respond to new challenges. Shifting from phenotype-based selection to genotype-based selection has the potential to overcome lengthy cassava breeding cycles. Using Genomic Selection, IITA has embarked on a one-year breeding cycle which is expected to increase the rate of genetic gain. The first cycle has been completed and we are on to the second cycle.
Annual breeding cycle using GS in cassava

21. Genomic selection-based population improvement
Boxplots showing realized selection gain (shifts in population mean) for key traits in selection index
Boxplots showing the performance of clones is a realized selection gain trial involving clones from Cycle 0, 1 and 2 clones planted in the same field in two locations.

24. A global open access resource
Cassavabase:
A global open access resource
All Data Available with Open Access with agreement to observe the
Toronto Protocol regarding use of unpublished data

25. Cassava Breeding Family and Partners
Thank You ‘