Progress and Achievements in the Genetic Enhancement and Breeding of Cassava for Sub-Saharan Africa
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Progress and Achievements in the Genetic Enhancement and Breeding of Cassava for Sub-Saharan Africa

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Development and improvement of cassava source populations,Major Disease/Pest Constraints of Cassava,Agronomic characteristics, pest reactions of promising micronutrient-rich clones,Polyploid......

Development and improvement of cassava source populations,Major Disease/Pest Constraints of Cassava,Agronomic characteristics, pest reactions of promising micronutrient-rich clones,Polyploid breeding for enhanced micronutrient content,Yam Genetic Improvement

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  • 1. 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
  • 2. Five main roles• Famine reserve crop• Rural food staple• Cash crop for urban consumption• Industrial raw material Food and• Earner of foreign exchange Beverage Paper Mono- sodium glutamate Wood CASSAVA Oil drilling Animal Feed Textile Ethanol International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 3. 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
  • 4. 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
  • 5. Breeding objectives for the development of new cassava varieties in SSA1. 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 type6. Good adaptation to major agroeecologies and production systemsGeographical Focus Humid forest, moist savanna, dry savanna and midaltitude agroecological zones. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 6. Major LinkagesNARS• 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 7. 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
  • 8. Development and improvement of cassava source populations Basic Strategy of Cyclical Selection of Source Population Develop a Source Population Inter-cross Evaluate Superior Progeny Progeny Select Superior Progeny International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 9. Ploidy Manipulation Unilateral and Bilateral Sexual Polyploidization (2x X 2x, 2x X 4x, 4x X 2x, 4x X 4x crosses) Somatic PolyploidizationSexual Colchicine (0.1%) Sol’n Somatic SexualDiploids (2x) Tetraploids (4x) X Tetraploids (4x) Improved Diploids X Improved Tetraploids (2x) (4x) Productive Triploids (3x) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 10. Germplasm Introduction (further broaden the genetic base)CIAT (2003): 38 clones [Latin American landraces (Brazil, Colombia, and Peru),South-east Asian landraces (Thailand) targeting whitefly resistance, high starchcontent, good eating quality, and agroecological adaptation to the lowland humid,acid savanna, and midaltitude agroecologies.Agronomic Institute of Campinas, Sao Paulo, Brazil, Brazil (2005): Industrialvarieties of six elite lines and landraces (high starch and cold tolerant) includingyellow-fleshed lines (IAC 576-70, IAC-12,IAC-14, FECULA-3, ESPETO-7, andBRANCA 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 cultivatedcassava x Manihot walkerae for delayed onset of postharvest physiologicaldeteriorationLatin Amerian lines (breeding lines and land races) with higher storage rootprotein and yellow fleshed rootsFive genotypes and 50 tissue culture derived plantlet from seeds of the firstbackross generation of selected interspecific progenies for high protein.Swiss Federal Institute of Technology, Zurich (2007): Some cassava lines for highstarch content from Asia (KU50, MThai 25Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org International Institute of and MThai 27).
  • 11. Acquisition of African adapted germplasm (2004)42 African varieties were introduced from South Africa as virus-tested in vitro plantlets in 2004 to enrich IITA breeding populationwith African adapted gene pools Tanzania Landraces and improved varieties 18 Malawi Landraces and improved varieties 14 Zambia Landraces and improved varieties 11Acquisition of micronutrient rich (beta carotene) seed populationsCIAT 2005: = 207 families (4754 seeds)EMBRAPA, Brazil (through CIAT) 2005: Micronutrient rich(betacarotene)=59 families (8074 seeds) • Evaluation, introgression into breeding pools and selection International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 12. Major Disease/Pest Constraints of CassavaMosaic Disease Bacterial Blight Anthracnose Root Rots Brown Streak Disease Mealybug Green Mite African Root and Tuber Scale International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 13. Host-plant Resistance Breeding 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 – Institut international d’agriculture tropicale – www.iita.org International Institute of Tropical Agriculture
  • 14. Relative Variety TME 419 FWS 12.14 DWF Rel. imp 3.58 27.40 improvement in 92/0326 15.14 3.63 29.18 forage yield of 97/4779 92/0057 14.66 18.78 3.7 31.67 3.82 35.94 improved varieties 98/0581 16.4 4.13 46.98 over the checks M98/0040 99/6012 15.09 15 5.18 84.34 8.51 202.85 30572 16.41 2.46 0.00• Among the 43 tested clones seven 4(2)1425 13.63 2.27 0.00 produced more forage compared to the 82/00058 18.47 3.71 0.00 control 96/1632 14.93 0.88 -68.68• They include clones 99/6012 (203%), 98/2226 15.47 1.13 -59.79 M98/0040 (84%), 98/0581 (47%), 92/0057 97/0211 9.51 1.48 -47.33 (36%), 97/4779 (32%), 92/0326 (29%) and 96/1569 7.21 1.68 -40.21 TME 419 (27%) 97/3200 14.63 1.74 -38.08• Cassava clone 99/6012 gave an 99/2123 19.36 1.77 -37.01 outstanding performance producing more 99/3073 16.46 1.77 -37.01 than thrice the forage yield obtainable in Mean 15.26 2.74 the three checks CV 18 45 SE 0.42 0.19FWS = Fresh weight shoot (t/ha); DWF = Dry weight forage (t/ha); Rel. imp = Relative improvementbased on DWF (%) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 15. Mean concentration of micronutrient @ 6, 9, &12MAP β-carotene (μg/g) Iron Zinc (mg/kg) (mg/kg)MAP 6 9 12 9 12 9 12Mean 0.33 3.08 2.09 9.36 6.52 9.04 7.93SE 0.25 0.88 0.65 0.8 0.78 0.57 0.54β-carotene 6 & 9 MAP DF =24 T value = -7.96 p <.0001β-carotene 6 & 12 MAP DF =24 T value = -7.34 p <.0001β-carotene 9 & 12 MAP DF =24 T value = 2.53 p = .0182Iron 9 & 12 MAP DF =24 T value = 5.24 p <.0001Zinc 9 & 12 MAP DF =24 T value = 2.68 p =.0132 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 16. Screening for Carotenoids, Fe & Zn Carotenoids (fresh wt basis)Year Total Total Screening method Deep Light Min Max No. No. yellow yellow TC TC families plants selected selected2004/05 476 16,832 Color chart, 24 379 - 10.1 spectrophotometric μg/g †2005/06 982* 19,644 Color chart, 895 1386 2.8 11.9 spectrophotometric μg/g μg/g2006/07 490 8743 Color chart, 667 158 1.23 14.81 spectrophotometric μg/g μg/g2007/08 638 28,865 Color chart, 1548 >500 1.56 13.27 spectrophotometric*Comprised of 133 families from CIAT, 59 from Brazil, and 790 local crosses from IITA Ibadan ; †obtainedfrom 2005 clonal evaluation. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 17. Fe and Zn (dry wt basis)Year No. No. Screening Max Max families plants method Fe Zn2004/05 476 16,832 - - -2005/06 982 19,644 ICPAES - -2006/07 490 8743 ICPAES 56.81 73.78 mg/kg mg/kg2007/08 638 28,865 ICPAES International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 18. GxE 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)International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 19. 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
  • 20. Agronomic characteristics, pest reactions of promising micronutrient-rich clonesClone CMD CGM Yield DM Carotene Fe Zn (t/ha) (%) (µg/g) mg/kg mg/kg05/1601 1.0 2.0 36.5 38.9 9.4 10.7 12.205/1600 3.2 2.5 34.5 29.0 6.5 9.0 12.005/1570 1.0 2.0 33.3 41.9 2.4 7.9 12.305/0327 1.0 4.5 28.4 37.8 6.2 6.5 14.305/1862 1.2 2.5 27.1 39.3 4.5 7.7 10.305/0311 1.0 2.5 25.7 40.9 5.5 7.2 8.305/0099 1.0 2.0 25.1 38.9 5.8 7.0 8.905/1654 1.0 3.0 23.0 34.9 6.9 17.4 15.105/0476 1.0 3.0 19.7 40.3 4.0 8.9 10.505/1652 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
  • 21. G x E: YLD, DM, DY G effect highest for DM E effect highest for YLD G x E*** for all traitsInternational Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 22. Percentage nutrient retention during traditional processing of yellow-fleshed cassava storage roots 120 Percent true retention 100 80 01/1371 60 01/1235 94/0006 40 20 0 Sun-dried Raw fufu Cooked Boiled gari chips fufu cassava Processed product Highest nutrient retention in boiled rootsMaziya-Dixon et. al., 2007.Submitted to LWT-J. Food Science International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 23. Carotenoid concentration at different steps of processing cassava storage roots to gari 18 16 Total carotenoid(ug/g) 14 12 TMS94/0006 10 TMS01/1235 8 TMS01/1371 6 4 2 0 Peeled raw Grated Grated and Fermented Roasted gari cassava cassava fermented pressed granules roots mash mash mash/cakeMaziya-Dixon et al., 2007. Int. J. Food Science and Technology. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 24. 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
  • 25. Polyploid breeding for enhanced micronutrient content 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 26. 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
  • 27. Descriptive statistics for chemical composition of cassava leaves (DWB) of 630 genotypes Total Starch Protein Dry Fat Tannin sugars (%) (%) Matter (%) (%) (mg/100g) (%)Mean 8.49 16.17 30.12 26.37 6.05 8.85SE 0.16 0.17 0.08 0.11 0.04 0.08Min. 2.4 4.0 25.6 18.0 1.3 4.0Max. 62.8 35.3 38.0 53.0 14.9 17.2Pr. > 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
  • 28. Descriptive statistics for chemical composition of cassava storage roots(DWB) of 637 genotypes CNP1 Total Starch Protein Ash Amylose Dry sugars (%) (%) (%) (%) 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
  • 29. Descriptive statistics for functional (pasting) characteristics of cassava storage roots of 637 genotypes Peak Breakdown Final Setback Peak time Pasting viscosity viscosity viscosity viscosity (Min.) temp.( C)Mean 196 115 112 32 4.63 82SE 2.22 1.45 2.14 0.69 0.02 0.62Min. 52 26 2.5 0.2 1.9 50Max. 633 479 265 106 7.0 89Pr. > 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
  • 30. There is a relationship between physical, chemical, and functionalWhat we learned 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
  • 31. Shift in nutrient levels with breeding and selection for root nutritional quality 2003/2004 2006/2007 % increaseβ-carotene 4.8μg/g 13μg/g >150Iron 10.3mg/kg >35mg/kg >200Zinc 10.3mg/kg > 60mg/kg >400Protein 1-4% >25% >400 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 32. Deployment of in vitro germplasm Virus-free certified tissue culture plantlets International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 33. HS seed families of beta-caroten enriched parental clonesCountry Seed families No. of seedsGuinea 71 10,100Congo DR 30 10,000Uganda 64 10,100Kenya 23 23,000Malawi 24 24,000Angola 23 23,000Mozambique 23 23,000Sierra Leone 23 46,000Ghana 17 18,100 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 34. Some official varietal releases of improved cassava by NARS between 2004 and 2007Year Country Variety name2004 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 Rushinga2005 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
  • 35. Nouvelles variétés en diffusion 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 9.46CMD score of 1-5 whereInternational Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org 1=no symptoms and 5 =severe damage
  • 36. Capacity building and technology disseminationDegree and non-degree trainingTraining of TrainersDemand-driven processing workshops International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 37. Summary of the progress and achievements 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). International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 38.  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
  • 39. Public Awareness and AdvocacyMinister of Agriculture and seniorofficials of FMARD–IITA (10 Feb) Dignitaries at the high table during the VP, FGN on a visit to IITA book launch International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 40. Yam Genetic Key challengesImprovement • Planting materials • Labour • Germplasm • Soil fertility • Diseases and pests (including weeds) • Post-harvest handling and processing International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 41. High and stable yield of marketable tubersGenetic (per unit of area, labour and time)Improvement Pest and disease resistanceObjectives (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) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 42. Focus on Dioscorea rotundataSelected Food D. alataYams D. cayenensis D. dumetorum D. burkilliana D. bulbifera D. esculenta D. opposita D. japonica D. trifida D. nummularia D. abyssinica D. praehensilis International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 43. Planting Materials•Whole tuber•Tuber fragment•Milking (double harvest)•Multiple tuberisation•Bulbil formation International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 44. Mounds for ceremonial yam Mounds in savanna zone Staking in forest zone Staking in savanna zone International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 45. Labour Saving 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 46. 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
  • 47. Viruses 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 48. Example of delivery of new clones of D.rotundata to partners in a yearCountry Partner No. of clonesBenin INRAB 234Cote d’Ivoire CSRS 80Ghana CRI & WASDU 169Nigeria NRCRI 104Togo ITRA 166 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 49. Varietal National Root Crops Research Institute, Nigeria: Three new varieties of D. rotundata in 2001releases Four new varieties of D. rotundata in 2003 Crops Research Institute, Ghana: Three new varieties of D. rotundata in 2005 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 50. NematodesResistanceidentified inDioscoreadumetorumbut not in Cracks & flaking of skin Necrotic spots Dry rotthe two Damage caused by Scutellonema bradysdominantspecies –D. alataand D.rotundata Galls Galls & crazy roots Galls and rot Damage caused by Meloidogyne spp. International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 51. Insect pests of yam tubers Mealybugs Scale insects Yam beetles Tuber moth damage International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 52. Internal Brown Spot International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 53. Opportunities International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 54. Colonization (%) of roots of Dioscorea alata by VAM fungi at 4 sitesin NigeriaClone Site Abuja Ibadan Onne Ubiaja MeanTDa 85/00250 68.00 84.72 39.94 88.32 70.25TDa 00/00064 78.23 45.09 61.06 88.84 68.31TDa 00/00104 75.55 55.58 51.98 89.23 68.09TDa 92-2 72.90 20.91 34.65 75.77 51.06TDa 99/00395 44.49 45.69 34.78 77.29 50.56TDa 02/00193 58.97 35.78 48.64 54.64 49.51TDa 93-36 50.54 28.47 32.48 82.38 48.47Mean (36 clones) 68.64 45.15 44.31 78.20 59.08S.e.d: clone = 6.3, location = 2.1, clone x location = 12.6CV% = 26.1 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 55. Colonization (%) of roots of Dioscorea rotundata at 4 sites in NigeriaClone Site Abuja Ibadan Onne Ubiaja MeanTDr 97/00588 85.42 78.89 58.38 81.23 75.98TDr 89/02665 79.38 44.53 78.01 71.50 68.36TDr 96/01799 79.03 47.67 77.33 69.00 68.26TDr 96/00528 53.73 49.57 52.90 31.25 46.86TDr 97/00903 62.38 47.53 1.12 69.78 45.20TDr 97/00632 56.73 31.45 51.37 40.47 45.01EHOBIA 33.18 30.53 28.83 44.25 34.20Mean (for 34 clones) 67.99 43.04 57.11 59.73 56.97S.e.d: clones = 6.54; Location = 2.24; Clone x location = 13.07CV (%) = 28.1 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 56. Tuber Density of Screening for tuber contents of total carotenoids, iron, zinc, ascorbic acid, and phytic acidMicronutrients 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 57. Tuber Density of Tuber content of ascorbic acid (in mg/100g fwb) :Micronutrients 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 58. Tuber nutrient contents of 31 genotypes of D. rotundata evaluatedat 4 sites over two years in Nigeria Iron Zinc Ascorbic acidSOV DF MS % SS MS % SS MS % SSTotal 371 4.90 3.94 2.46TRT 123 9.74*** 65.8 9.02*** 75.8 4.76*** 64.2GEN 30 13.76*** 34.4 23.08***62.4 5.68*** 29.2ENV 3 115.94***29.0 45.60***12.3 61.40*** 31.5GxE 90 4.86*** 36.5 3.10*** 25.2 2.56*** 39.4 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 59. Micronutrients 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) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 60. Descriptive statistics for functional (pasting) characteristics of 33 genotypesof D. rotundata grown at Abuja, Nigeria Peak Breakdown Final Setback Peak time Pasting viscosity viscosity viscosity viscosity (Min.) temp.( C)Mean 209 38 247 76 6 84SE 11.7 6.6 12.86 7.66 0.11 0.17Min. 69 4 97 29 5 82Max. 338 147 397 209 7 86Pr. > 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
  • 61. Evaluation of Dioscorea alata varieties for making pounded yamMean pasting 350.00properties of D. 300.00alata and control 250.00 200.00 D. alata 150.00 D. rotundata 100.00 50.00 0.00 gh n . k p. . e is c ow isc ac t im m ou lv tb V kd te Tr ng Se na ak ea ng sti Fi Pe Br sti Pa Pa International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 62. 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= moderatelyinferior, 4 = slightly inferior, 5= no difference, 6= slightly better, 7=moderatelybetter, 8=much better, 9= extremely better International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 63. Benin Institut National des Recherches Agricoles du Benin (INRAB) Centre régional de Nutrition et d’Alimentation Appliquées (CERNA)Key NARS Cameroon University of DschangPartners 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) International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org
  • 64. Other Research • CIRAD, FrancePartners • 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 International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org