GRM 2013: Improving and deploying markers for biotic stresses in cassava -- C Egesi

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GRM 2013: Improving and deploying markers for biotic stresses in cassava -- C Egesi

  1. 1. Improving and deploying markers for biotic stresses in cassava GCP Project #: G7010.01.02 Chiedozie Egesi NRCRI, Nigeria
  2. 2.  Biotic constraints of cassava in Africa  Mapping and new QTLs for cassava mosaic disease (CMD)  Pyramiding of QTLs for CMD  Validating QTLs for cassava brown streak disease (CBSD)  Mining for resistance genes for cassava bacterial blight (CBB) and cassava green mite (CGM)  Summary Outline
  3. 3. Cassava brown streak diseaseCassava bacterial blight Cassava mosaic disease Cassava green mite Each could cause yield losses of 30 to 100% Major Biotic Constraints in African Cassava Productivity
  4. 4.  To develop mapping populations for CMD  To identify and map QTLs for new sources of CMD  To develop populations for validation of QTLs for CBSD  To identify sources of resistance to CGM and CBB Specific Objectives
  5. 5. New QTLs for CMD
  6. 6. Umudike: 97/2205 x 30555 N=340 Frequency distribution of severity scores for CMD in 2 mapping populations in Umudike and Otobi Otobi: 96/1089A x 30555 Otobi: 97/2205 x 30555 Umudike: 96/1089A x 30555 N=141 Disease severity scores from 1 to 5. Plants with scores 1-2 are considered resistant.
  7. 7. Mean symptom severity scores for CMD in 2 mapping populations in Umudike and Otobi Family Trial Severity scores of parents Severity scores of progenies 30555 97/2205 Check Lowest Highest F-value 97/2205x30555 Otobi 3 1 3.82 1 5 4.31*** N = 340 Umudike 3 1 2.76 1 4.04 2.72*** 30555 96/1089A Check Lowest Highest F-value 96/1089Ax30555 Otobi 4 1 4.08 1 4 5.14*** N = 141 Umudike 2.6 1 2.5 1 4.08 1.39*
  8. 8. Linkage group size for SNP markers from family 97/2205 x 30555 Linkage group Number of markers Average marker interval (cM) Size (cM) 1 48 2.13 102.3 2 35 3.57 125.1 3 37 3.59 132.8 4 51 1.98 100.9 5 46 2.48 114.2 6 34 1.28 43.5 7 40 2.93 117.0 8 41 1.94 79.6 9 37 3.09 114.3 10 35 3.96 138.6 11 34 3.34 113.4 12 32 3.63 116.1 13 25 5.43 135.7 14 18 4.52 81.4 15 14 2.16 30.3 16 13 4.47 58.1 17 29 3.01 87.3 18 8 2.21 17.7 Total/Average* 577 3.1* 94.9*
  9. 9. SNP genetic linkage map of family 97/2205 x 30555
  10. 10. QTLs associated with resistance to CMD Chr Position Left Marker Right Marker LOD 2 501 md076 md077 24.3743 4 1703 md168 md170 21.9322 8 636 md333 md334 18.4417 10 290 md402 md403 26.5707 13 358 md504 md506 23.5867
  11. 11. QTLs associated with resistance to CMD
  12. 12. Pyramiding of QTLs for CMD
  13. 13.  Combining CMD2 and new QTLs to broaden resistance  Crosses derived from parents with new QTLs already being phenotyped  ca. 100 progenies in multi-site trials for resistance to CMD  Integration of SSR and SNP maps and markers for consensus maps/QTLs Pyramiding of QTLs for CMD
  14. 14. Validating QTLs for CBSD
  15. 15. Populations developed and segregating for CBSD in Tanzania Parents Number of F1 Seeds derived Number of seedlings established Resistant Susceptible Namikonga AR37-80 5551 621 Kiroba 3C83-13 926 334 Muzege Cheupe 657 111 B2C20-65 AR37-80 302 150 Total 7436 1216  Evaluation for the second year in Tanzania is nearing completion  Markers derived from a BMGF project to be used for validation
  16. 16. Frequency distribution for CBSD in 4 mapping populations 0 20 40 60 80 100 120 1 2 3 4 5 Muzege x Cheupe CBSD 6 MAP 0 20 40 60 80 100 120 1 2 3 4 5 Muzege x Cheupe CBSD 3 MAP 0 20 40 60 80 100 120 1 2 3 4 5 B2C20-65xAR 37-80 CBSD 3 MAP 0 20 40 60 80 100 120 140 1 2 3 4 5 B2C20-65 x AR 37-80 CBSD 6 MAP 0 100 200 300 400 500 600 700 1 2 3 4 5 Namikonga x AR 37-80 CBSD 3 MAP 0 100 200 300 400 500 600 1 2 3 4 5 Namikonga x AR 37-80 CBSD 6MAP 0 50 100 150 200 250 300 1 2 3 4 5 Kiroba x 3C83-13 CBSD 3 MAP 0 50 100 150 200 250 300 1 2 3 4 5 Kiroba x 3C83-13 CBSD 6 MAP 0 20 40 60 80 100 120 1 2 3 4 5 Muzege x Cheupe CBSD 9 MAP 0 20 40 60 80 100 1 2 3 4 5 B2C20-65 x AR 37-80 CBSD 9 MAP 0 100 200 300 400 500 600 1 2 3 4 5 Namikong x AR 37-80 CBSD 9 MAP 0 50 100 150 200 250 300 1 2 3 4 5 Kiroba x 3C83-13 CBSD 9 MAP
  17. 17. Mining for resistance gene donors in African cassava to cassava bacterial blight (CBB) and cassava green mite (CGM)
  18. 18. 1. Leaf blighting, brownish vascular discoloration 2. Wilting 3. Die back & rapid defoliation=‘candle sticks’ 1, 3 2 1 1 4 5 Cassava Bacterial Blight (CBB)
  19. 19. CGM Cassava green mite (CGM) symptoms
  20. 20.  Field evaluation for two years  Multi-site, replicated trials Germplasm assessed for resistance to CBB and CGM Population Type Number of Accessions Trait Assessed Landraces 256 CBB, CGM Improved 183 CBB, CGM Total 439
  21. 21. 23.0 74.2 2.7 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 R MS HS Frequency(%) R = Resistant; MS = Moderately susceptible; HS = Highly susceptible 21.46 52.79 25.75 0.00 10.00 20.00 30.00 40.00 50.00 60.00 R MS S Frequency(%) CBB CGM Distribution of 256 African casssava landraces for resistance to cassava bacterial blight (CBB) and cassava green mite (CGM)
  22. 22. 13.4 59.3 27.3 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 R MS HS Frequency(%) 30.2 46.1 23.5 0 5 10 15 20 25 30 35 40 45 50 R MS HS Frequency(%) CBB CGM R = Resistant; MS = Moderately susceptible; HS = Highly susceptible Distribution of 183 improved casssava genotypes for resistance to cassava bacterial blight (CBB) and cassava green mite (CGM)
  23. 23. NRCRI germplasm CBB score CGM score IITA germplasm CBB score CGM score NR/8010 1 1 188/023543 1 1 74/2 1 2 189/00748 1 1 74/640 1 2 TME-226 1 1 73/30 1 2 T983/00016 1 1 73/192 1 2 188/01226 1 1 73/404 1 2 088/00623 1 1 75/647 1 2 TME-236 1 2 75/726 1 2 TME-478 1 2 77/169 1 2 088/00378 1 2 TMX4009 1 2 087/00183 1 2 Disease and pest severity scores on the basis of 1 to 5 where 1 is no symptom and 5 is very severe symptoms Clones identified with combined resistance to cassava bacterial blight (CBB) and cassava green mite (CGM)
  24. 24.  New mapping populations for CMD and CBSD formed and evaluated  QTLs for resistance to CMD identified  Pyramiding of different sources of resistance to CMD commenced  New sources of resistance to CGM and CBB identified Summary
  25. 25. Acknowledgements NRCRI, Nigeria Emmanuel Okogbenin Joseph Onyeka Others CRI, Ghana Elizabeth Parkes Bright Peprah Others ARI, Tanzania Geoffrey Mkamilo Heneriko Kulembeka Others GCP Xavier Delannay Chunlin He Others Project Partners
  26. 26. Thank You!

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