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Enhancing Corn Resilience to Aflatoxin: GEM Accessions Evaluation

Assessing agronomic performance and aflatoxin resistance in corn accessions. Objectives include identifying resistant germplasm and associated genes. Research focuses on increasing vulnerability factors to A. flavus.

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Enhancing Corn Resilience to Aflatoxin: GEM Accessions Evaluation

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  1. Assessing GEM accessions for agronomic performance and resistance to aflatoxin accumulation in grain in the Midsouth. Mike Clements

  2. USDA-ARS Corn Host Plant Resistance Research Unit Located at

  3. Objectives of CHPRRU: Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation

  4. Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation Objectives of CHPRRU: Identify/develop germplasm with favorable agronomics and resistance to A. flavus infection, aflatoxin accumulation, and insect feeding.

  5. Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation Identify germplasm with resistance to A. flavus infection, aflatoxin accumulation, and insect feeding. Objectives of CHPRRU: Identify proteins, molecular markers, and genes associated with resistance.

  6. Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation Identify/ develop germplasm with favorable agronomics and resistance to A. flavus infection, aflatoxin accumulation, and insect feeding. Objectives of CHPRRU: Identify proteins, molecular markers, and genes associated with resistance.

  7. Identify/ develop germplasm with favorable agronomics and resistance to A. flavus infection, aflatoxin accumulation, and insect feeding. My role within CHPRRU: Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation Identify proteins, molecular markers, and genes associated with resistance.

  8. Identify/ develop germplasm with favorable agronomics and resistance to A. flavus infection, aflatoxin accumulation, and insect feeding. My role within CHPRRU: Release resistant, agronomically favorable Inbred lines Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation Identify proteins, molecular markers, and genes associated with resistance.

  9. Identify/ develop germplasm with favorable agronomics and resistance to A. flavus infection, aflatoxin accumulation, and insect feeding. My role within CHPRRU: Release resistant, agronomically favorable Inbred lines Publish information Determine biotic and abiotic factors that increase vulnerability of corn to A. flavus infection and aflatoxin accumulation Identify proteins, molecular markers, and genes associated with resistance.

  10. My objectives: • Develop a rapid, inexpensive assay for screening • a large quantity of samples

  11. My objectives: • Develop a rapid, inexpensive assay for screening • a large quantity of samples • Identify novel sources of resistance • with an eye toward yield!

  12. My objectives: • Develop a rapid, inexpensive assay for screening • a large quantity of samples • Identify novel sources of resistance • with an eye toward yield! • Develop and release inbred lines with superior • resistance and functional agronomics that are • useful for private and public breeding programs

  13. My objectives: • Develop a rapid, inexpensive assay for screening • a large quantity of samples • Identify novel sources of resistance • with an eye toward yield! • Develop and release inbred lines with superior • resistance and functional agronomics that are • useful for private and public breeding programs • Collaborate!

  14. Why GEM? Collaborative effort: USDA-ARS Land-grant universities Industry Objective: Widen the germplasm base of commercial hybrid corn by introducing and incorporating novel, useful germplasm gathered from around the globe.

  15. Evaluation of GEM Accessions 2003 - 2004 Inoculated, replicated trials at Mississippi State, MS Characteristics examined: + Aflatoxin concentration in grain + Severity of Aspergillus ear rot + Maturity (MGDU planting to silking) -- Grain quality and weight -- Plant characteristics

  16. Tropical Sub-tropical Evaluation of GEM Accessions 2003 - 2004 • 28 GEM breeding crosses • Temperate x “Exotic”

  17. Tropical Sub-tropical Evaluation of GEM Accessions 2003 - 2004 • 28 GEM breeding crosses • Temperate x “Exotic” • - 25 to 50% exotic

  18. Tropical Sub-tropical Evaluation of GEM Accessions 2003 - 2004 • 28 GEM breeding crosses • Temperate x “Exotic” • - 25 to 50% exotic • Most genes not “fixed” • (~100% heterozygous)

  19. Evaluation of GEM Accessions 2003 - 2004 • 127 GEM lines • Selected from breeding crosses for • yield, agronomics or value added traits.

  20. Evaluation of GEM Accessions 2003 - 2004 • 127 GEM lines • Selected from breeding crosses for • yield, agronomics or value added traits. • - % exotic??

  21. Evaluation of GEM Accessions 2003 - 2004 • 127 GEM lines • Selected from breeding crosses for • yield, agronomics or value added traits. • - % exotic?? • Most genes “fixed” • (~75 to 97% homozygous)

  22. Evaluation of GEM Accessions 2003 • 83 testcrosses of GEM lines • - GEM line x commercial inbred Suggestive of hybrid performance

  23. Evaluation of GEM Accessions 2003 • 83 testcrosses of GEM lines • - GEM line x commercial inbred Suggestive of hybrid performance Unfortunately, multiple testers! Value of comparisons among testcrosses was minimized

  24. GEM Breeding Crosses 2003 - 2004

  25. Resistant Resistant Mod Resist Susceptible Susceptible

  26. GEM Lines 2003 - 2004

  27. GEM Lines 2003 - 2004

  28. GEM Lines 2003 - 2004

  29. 2003-2004 Top Resistant GEM Lines Resistant Resistant Resistant Mod Resistant Susceptible

  30. 2003-2004 Top Resistant GEM Lines Resistant Resistant Resistant Mod Resistant Susceptible

  31. 2003-2004 Top Resistant GEM Lines Resistant Resistant Resistant Mod Resistant Susceptible

  32. 2003-2004 Top Resistant GEM Lines Resistant Resistant Resistant Mod Resistant Susceptible

  33. Testcross aflatoxin eval 2005 • 16 GEM lines identified as resistant or susceptible in • previous work • 5 public inbred lines • (Mp494, Mp715, Mp80:04, NC258, NC320, Tx601) • 10 experimental lines from USDA-ARS at MS State. • 1 commercial check (Terral Seeds TV2100), • 1 susceptible check (GA209/SC212M) • 1 resistant check (Mp313E/Mo18W), • The cross LH195/LH210.

  34. Top lines: Testcross aflatoxin eval 2005 Resistant Resistant Resistant Resistant

  35. Top Resistant GEM Lines Testcrossed to LH195 or LH210 Resistant Resistant Resistant Mod Resistant Susceptible

  36. GEM Lines – Yield data (x LH287) 2001 data from 13 Southern Locations 2002 data from 6 Southern Locations

  37. GEM Lines – Yield data (x LH185Bt) 2001 data from 13 Southern Locations 2002 data from 6 Southern Locations

  38. GEM Lines – Yield data (x LH185) 2002 data from 6 Midwest Locations

  39. GEM Lines – Yield data (x LH185) 2002 data from 6 Midwest Locations Majority of these lines selected in North Carolina!

  40. Testcross Yield Trial 2005 • 145 GEM lines • 9 public inbred lines • (Mp420, Mp494, Mp715, Mp80:04, Mp717, NC258, • NC298, NC320, Tx601) • 4 experimental lines from USDA-ARS at, MS State • 3 commercial checks • (Pioneer Brand P3394, Terral Seeds TV2100, Dekalb • DK697) • The cross LH195/LH210

  41. Testcross Yield Trial 2005 X LH195 X LH210

  42. Continuing Research W. Paul Williams Tom Brooks CHPRRU, MS State

  43. Continuing Research Resistant Susceptible Susceptible

  44. Continuing Research Resistant Susceptible Susceptible

  45. Thanks!

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