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2.3 mas cassava esther masumba

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  • 1. Application of marker assisted selection: A strategy to improve cassava production in Tanzania Esther Andrew Masumba Root/Tuber Research Program Tanzania
  • 2. Importance of Cassava Cassava is among the primary staples in some areas within Tanzania. Ranks second after maize It is among the leading food security crops in Tanzania It strives well in marginal soils and drought prone climates Hence, liable to positively cope with the current climate change effects Cassava plant
  • 3. Utilization of Cassava Domestic consumption Tubers: Fresh Flour making (Ugali) Cooked/boiled Crisps Leaves: As vegetable
  • 4. Utilization cont. Cassava cake Industrial raw material: Food industries Confectioneries (cakes, biscuits, etc) Bakeries (breads) Cassava biscuits Weaning food for babies e.g. Power foods (agro processing company) Bread
  • 5. Utilization cont. Starch production Ethanol production e.g. 280 L (222kgs) of 96% pure ethanol from 1 ton of cassava roots with 30% starch
  • 6. Animal feed Cassava chips Silage
  • 7. Main cassava cropping zones in Tanzania High production Moderate production Low production
  • 8. National cassava production statistics Location (zones) Production (%) Production (tones) Eastern & Southern 48.8 2,684,000 Lake 23.7 1,303,500 Southern Highlands Western Central Others TOTAL 13.7 7.9 5.0 0.9 100 753,500 434,500 276,100 49,510 5,451,600
  • 9. Constraints in cassava production Average yield in the farmers fields ~ 10.5 tones per hectare. Far below the crop potential production potential of up to 90 tones per hectare. The decline is contributed by: o Low yielding ability inheritable to the varieties o Poor agronomic practices o Varieties susceptibility to existing pests and diseases (Major)
  • 10. Important diseases 1. Cassava mosaic disease (CMD) Symptoms: o Distortion of leaf shape o Reduction in leaflet size o General stunting Yield reduction of up to 95 percent o
  • 11. 2. Cassava brown streak disease (CBSD) Leaf symptoms Stem symptoms Root symptoms
  • 12. Causal agents and spread of both CMD and CBSD Causal agent: Viruses Spread: Whitefly (Bemisia tabaci)
  • 13. Control of CMD and CBSD Phytosanitation Selection of healthy planting materials Up rooting of diseased plants Use of tolerant/resistant varieties Developed through conventional breeding Marker assisted selection
  • 14. EFFORTS DONE BY ROOT/TUBER RESEARCH PROGRAM IN TANZANIA Molecular Marker-Assisted and Farmer Participatory Improvement of Cassava Germplasm for Farmer/Market Preferred Traits in Tanzania Project Phase 1: 2003 – 2006 (Rockefeller foundation funded) Phase 2: 2007 – 2009 (Alliance for Green Revolution in Africa funded)
  • 15. Objectives Improve local germplasm for cassava mosaic resistance using improved genotypes from CIAT Impalement Molecular Marker-Assisted (MAS) for Cassava Mosaic Disease to increase cost-effectiveness Train NARS breeders in Molecular breeding methods Involve end users and trade intermediaries in uptake
  • 16. Identification of markers associated with CMD resistance (CIAT) Tagging of CMD resistance gene CMD2 R Dist cM Marker Name rGY115 Molecular markers (SSR) that explain > 90% of phenotypic variance for CMD resistance, identified 7.9 rGY9 15.6 rGY1 16.1 CMD2 rSSRY28 11.3 Ai19 RME1, RME2, NS158 and NS169
  • 17. MAS Scheme to Improve Tanzanian Cassava Germplasm Introduce CMD resistant varieties from CIAT ≈ 90 (Year1) Controlled crossing (next slide) (Year 2) Seedling trial (60,000 seedlings) (Year 3) Single row trial ≈ 10,000 genotypes (Year 4) Local varieties with CBSD tolerance (selected by farmers) ≈ 60 (Year 1) MAS (Year 3) Farmer participatory trial ≈ 600 genotypes (Year 5)
  • 18. Development of resistant varieties Female flower: Adaptable and Tolerance to CBSD (Local variety) Male flower: With a molecular marker associated with CMD resistance (from CIAT, Colombia) X F1 s Fruits and seeds (Segregating population)
  • 19. Typical cassava conventional breeding scheme Year Activity 1 4 Collection , evaluation and selection of parents Crosses among elite clones planned, nurseries planted and pollinations made F1: Evaluation of seedlings from botanical seeds. Strong selection for CMD and CBSD in Africa Clonal evaluation trial (CET) 5 Preliminary yield trial (PYT) 6 Advanced yield trial (AYT) 2 3 7-9 Regional trials (RT) Number Plants per genotype Up to 100,000 100,000a; 50,0000b; 50,00 c 20,000–30,000a,b 700 c 100 a; 300 b; 80 c 25 a; 100 b; 20–25 c 5-30 a, b, c 1 6–8 (1 rep, 1 location) 20–60 (3 reps, 1 location) 100–500 (3 reps, 2–3 location) 500-4 000 (3 reps, 3–4 locations)
  • 20. Enhanced development, evaluation and official release of four CMD/CBSD resistant cassava varieties S/N Variety 1. Pwani Pedigree Female Male parent parent Namikonga AR 42-4 2. Mkumba Namikonga AR 42-4 3. Dodoma Kiroba AR 3x-1 4. Makutupora AR 11-12 Namikonga
  • 21. Recommended agro ecologies for the dissemination of the new varieties S/no Clone (Variety) Target zone Agro ecology 1. Pwani (B2C20-65) Eastern and southern Lowland warm sub humid 2. Mkumba (3C20-10) Southern Lowland warm sub humid 3. Makutupora (2C80-42) Central Mid to high altitude warm semi arid 4. Dodoma (BC231-2) Central Mid to high altitude warm semi arid
  • 22. Characteristics of the varieties S/no. Variety Maturity age Yield Root taste potential 1. Pwani 11 - 12 50.8 Sweet 2. Mkumba 9 -10 23.3 Sweet 3. Makutupora 9 - 10 30.3 Bitter 4. Dodoma 9 - 10 36.1 Sweet
  • 23. Thank you
  • 24. FUTURE PLANS Multiplication and dissemination of the officially released varieties to the farming communities

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