Cassava germplams characterization

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Cassava germplams characterization

  1. 1. TaxonomyKingdom : PlantaeDivision : MagnoliophytaClass : magnoliolpsidaOrder : MalpighialesFamily : EuphorbiaceaeSubfamily : CrotonoideaeTribe : ManihoteaeGenus : ManihotSpecies : M. esculenta
  2. 2. Introduction• Origin – Brazil• Highly cross pollinated crop• Duration – 7 months to 2 years• Introduced to Africa and Asia from south America• Grown in 90 countries
  3. 3. Contd…• Cassava ranks 4th after rice, sugarcane, and maize• Extensively cultivated countries are Argentina, Brazil, Colombia, and Paraguay• Area under cultivation – 16 mha• Provide food & livelihood for >500 million people in the world - Best and Henry, 1992
  4. 4. Contd… Biochemical aspectsRoot: Roots are mostly contain carbohydrates Also rich in vit.C, carotene, Ca, and K Poor in proteinLeaf: Rich in protein and vitamins Consumed as a vegetable
  5. 5. Genome structure• 2n = 36• Genome size - 1.67 pg 772 M bp in the haploid genome
  6. 6. GermplasmWorld germplasm collection held at CIAT, ColombiaHas around 5,724 accession Brazil – 1,340 accessions Colombia - 2,003 accessions • Kenya • Uganda • Rwanda • Burundi • Congo • Madagoscar
  7. 7. Wild speciesManihot anomalaM. caerulescenceM. epruinosaM. flabellifoliaM. glazioviiM. dichotomaM. tristisM. peruvianaM. maracasensis
  8. 8. UsesStarch as raw material for Paper industries Textiles Pharmaceuticals Animal feed Sago industries and also used as a poultry feed
  9. 9. MarkersPhenotypic marker• Graner (1942) described two morphological markers Leaf shape Root colour• Hershey & ocampo (1989) described eight morphological markers located on the stem, leaves, and root.
  10. 10. cassava phenotypic markers Organs Types • ErectPlant shape • Tall and spread • Spread 1. GreenColour of the 2. Yellow-greenyoung part of 3. Green and beginning of petiole redthe stem 4. Green and beginning of petiole red with red ribs 5. Green and red in equal area 6. Some traces of green 7. Entirely light red • GreenColour of the • coloured base and green scaleseye (bud) • Green base and coloured scales • Entirely coloured
  11. 11. Emergence of eye (bud) • Deep • ProjectingAlignment of internodes • Zigzag(young part) • Straightleaf shape • Palmipartite (normal shape) • Palmisequate (the lobes totally separate) • Entirely green • Yellowish greenColoration of petiole • Vivid red • Purple red • Entirely purple • Less than 3Number of leaf lobes • 3 to 5 • 5 to 7 • 7 to 9
  12. 12. •Very narrow •Parallel edgeShape of lobes •Normal •Wide •Rounded with two widening points •ProximalForm of lobes defined by position of •Medianmaximal widening point •Terminal •White without chlorophyll •Light greenColoration of upper surface of lamina •Yellow-green •Dark green •Purplish •Green •Whitish-greenColoration of underside of lamina •Yellow-green •Purple of red •Always green •red of upperside of young leavesColoration of lamina nerves •red on underside of young leaves •red on both side of young leaves
  13. 13. Leaf variation
  14. 14. Stem variation
  15. 15. Tuber variation
  16. 16. Inflorescence 1. WideForms of sepals 2. Medium 3. narrow 1. Entirely green Sepals colour in female 2. Green and coloured nerveflower 3. Red and green 4. Red to purple 1. Always straight Shape of 6 wings on the 2. Straight then sinous at maturityovary with 3 carpels 3. Sinous then straight at maturity 4. Always sinousOvary body colour 1. Green 2. Red
  17. 17. Root 1. Short ( < 40 cm ) Length of root 2. Normal ( 40 to 80 cm ) 3. Long ( > 80 cm) 1. Conical Shape of root 2. Fusiform 3. Cylindro-conical 4. cylindrical 1. Smooth Texture of root surfaces 2. Medium 3. Rough Appearance of external 1. Grey and thinbark 2. Brown and thick Colour of pulp 1. White 2. Yellow
  18. 18. Biochemical Marker• Isozymes – fingerprinting and genetic diversity studies (Hussain et al., 1987; Ramirez et al., 1987; Ocampo et al., 1992; Lefevere & Charrier., 1993a)• Applied to characterizing relationships among cassava accessions (Lefevere & Charrier, 1993b; Wanyera et al.,1994)• Alpha & beta esterase more informative,provide 22 alleles, which have complemented morphological descroptors for identification of duplicates in cassava germplasm (Ocampo et al., 1995)
  19. 19. Molecular / DNA Marker• Independent to environment• Stable• Important to study the genes, genomes, and genetic diversity.
  20. 20. Development of DNA markers1st generation DNA markers • RFLP (Grodzicker et al., 1974) • VNTR (Jeffrey’s et al., 1985) • ASO (Saiki et al., 1986) • AS-PCR (Saiki et al., 1986) • OP (Beckmann, 1988) • SSCP (Orita et al.,1989) • STS (Olsen et al., 1989)
  21. 21. 2nd generation DNA Markers• RAPD (Williams et al., 1990)• AP-PCR (Welsh and Mc Cleland, 1996)• STMS (Becknann& Soller, 1990)• RLGS (Hatada et al., 1991)• CAPS (Akopyanz et al.,1992)• DOP-PCR (Teknins, 1992)• SSR (Akkaya et al., 1992)• MAAP (Caetano-anolles et al., 1993)• SCAR (1993)
  22. 22. New generation markers IRAP ( 1998 ) REMAP ( 1999 ) MSAP ( 1999 ) MITE ( 2000 ) TE – AFLP ( 2000 ) IMP ( 2001 ) SRAP ( 2001 )Others ۩ ISSR ۩ SAMPL ۩ AFLP/SRFA ۩ ASAP ۩ CFLP ۩ ISTR ۩ SSAP ۩ RBIP
  23. 23. Molecular / DNA Markers used in Cassava • RFLPs (Botstein et al., 1980) • SSRs (Litt & Lutly, 1989a,b) • RAPDs (Williams et al., 1990) • Minisatellites (jeffreys et al., 1993) • AFLPs (Vos et al., 1995)
  24. 24. Relationship analysis of closely related species to cassava based on microsatellite PCR’ To study phylogenetic relationship between cassava and its closely related species from south America Manihot esculenta ssp esculenta M. esculenta ssp flabellifolia M. esculenta ssp peruviana M. pilosa M. triphylla
  25. 25. Contd…Multilocus markers are usedRAPD, AP-PCR, DAP, AFLP, & SSRRecently oligonucleotide based SSR used Two kinds of SSR data Sequence data base Specific genomic libraries
  26. 26. Contd… Result• Varied amplification• No of band is varied from 1 – 15• Fragment size varied from 200 – 3000 bp• Scored as dominant marker• Highest genetic diversity observed in M. esculenta ssp. Flabellifolia followed by, M. esculenta ssp esculenta, M. pilosa, M. esculenta ssp peruviana, M. triphylla
  27. 27. • CMD resistance conferred by dominant gene• BSA – Identify a SSR markers linked to the CMD resistant gene• 186 SSR markers are used
  28. 28. Contd…• Resistant gene – CMD 2• Flanked by SSRY28 & GY1 @ 9 and 8cM respectively• CMD resistant cassava – TME 3 X TMS 30555• 158 individual was established invitro from embryo axes the sub cloned• Transfer the plants into a field with low CMD pressure• CMD resistance evolved at 3 to 6 month old plant• Scoring – 1 to 5
  29. 29. Genetic mapping of a CMD resistant gene• 186 SSR markers – 80 SSR markers map positions are known• SSRY28 differentiate the CMD resistant genotype from CMD susceptible genotype• SSRY28 located on 17th chromosome of male- parent-derived molecular genetic map• Flanked by GY 1 & Ail 9b markers
  30. 30. Result• All 10 plants of each resist genotype in all 3 replication are showed without any visible symptoms• Susceptible genotypes are always heavily infected• SSRY 28 present in resistant genotypes and not in susceptible genotypes.
  31. 31. • Most popular• Dormaa, Wenchi, Nkoranza,& Asonafo• 50 Genotypes are taken• 4 primers (OPK-01, OPR-02, OPR-09, IOJ-14)• 41 different bands detected• Range of polymorphism % is 90% - 100%
  32. 32. 67 unlinked SSR loci assessed283 accessionsGrouped into 14
  33. 33. 76 varieties are grown in Rewa31 varieties – taken for AFLP analysis with some wild speciesTo assess: Intravarietal diversity Genetic variability in the local varieties
  34. 34. 78 accessions evolved • 1- breeding stock (clone 58308) • 5- improved lines • 10 - CMD susceptible • 62 - CMD resistant36 SSR Markers are used
  35. 35. Institutes• CIAT - Colombia• IITA - Nigeria• CDH - Africa• CTCRI - India, Indonesia, Tanzania• ESARC - Africa• INEAC - Belgian Congo• IRAT - West and Central Africa• IRAM - Madagascar• MARDI - Malaysia• IICA - Venezuela, Mexico, Brazil, Colombia, Costa Rica

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