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Amino acid analysis of GEM germplasm

Amino acid analysis of GEM germplasm. M. Paul Scott USDA-ARS Ames, Iowa 50011 pscott@iastate.edu. U.S. Corn Uses National Corn Growers Association, 2004. Annual value: $25 Billion. Impact of increased ethanol production. Corn Prices Up Corn Acres Up Soybean price Down

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Amino acid analysis of GEM germplasm

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  1. Amino acid analysis of GEM germplasm M. Paul Scott USDA-ARS Ames, Iowa 50011 pscott@iastate.edu

  2. U.S. Corn UsesNational Corn Growers Association, 2004 Annual value: $25 Billion

  3. Impact of increased ethanol production Corn Prices Up Corn Acres Up Soybean price Down Gov’t Payments Down Livestock income Slight decrease Overall Farm income Up N, P Lost to water Up Soil Erosion Up Source: WRI policy note,2006 Marshall & Greenhalgh

  4. Food and Fuel Grain Oilseeds Petroleum Starch Protein Oil Protein Oil hydrocarbons Food Transportation Feed

  5. Grain Oilseeds Starch Protein Oil Protein Oil Petroleum 3.9 Billion Gallons EtOH in 2005 13% of Corn crop Food Transportation Feed 146 Billion Gallons Gasoline used/year in US Food and Fuel

  6. A solution Petroleum Lignocellulosic Biomass Grain Oilseeds Starch Protein Oil Protein Oil Food Transportation Feed Grain + Ethanol Co-products: DDGs

  7. What corn traits are important? • Yield (insect, disease, drought …) • N use efficiency • What about quality traits?

  8. Grain Ethanol Production Protein 10% Fiber 3% Fat 4% Starch 75% Protein is concentrated by ethanol production! Problems are amplified! Corn Protein, Fiber, Fat Starch 18 lb/bu $0.68/bu 2.7 gal/bu $4.32/bu EtOH Protein 30% Fiber 10-50% Fat 10-20% Starch 5% Co-products: DDGS, Solubles

  9. Water Salt Alcohol Base Albumins Globulins Prolamins “Zeins” Glutelins Seed FractionationOsborn, 1924

  10. Seed Proteins Endosperm-storage Embryo-vegetative Zeins SDS-PAGE Coomassie Blue Stained

  11. Zeins • Zeins are so abundant that they have a large impact on protein quality of grain • Zeins are concentrated in ethanol co-products so their impact is even greater • Zeins are nutritionally poor for non-ruminants • They are poorly digested • They are deficient in certain essential amino acids

  12. Amino acid levelsCorn vs. Egg

  13. Nutritionally limiting amino acids Methionine is the limiting AA in Poultry diets Lysine is limiting in poultry and swine diets, but can be supplemented inexpensively Tryptophan is limiting in swine diets

  14. Absolute amino acid level What corn traits are important? • Yield (insect, disease, drought …) • N use efficiency • For Ethanol: • Fermentable starch • Protein quality • Available P • For non-ruminant feed: • Protein content • Protein quality • Available P Amino acid/ protein

  15. Questions about biofuel co-products • How are differences in grain composition reflected in co-product composition? • How will co-products be improved by processing? • Can yeast components be used to complement grain components in co-products?

  16. Evaluation of amino acid content of GEM germplasm • About 80 GEM accessions / year selected for agronomics and past AA performance. • Good lines are re-tested in subsequent years • Lys, Met, Trp, Index (Lys,Met,Trp) • Checks: • B101 (high Met) • B45o2 (high Lys, Trp) • B73xMo17, B73, Mo17, B45

  17. Microbial assay for Met Low High Met Concentration

  18. Evaluation of amino acid composition of GEM germplasm Two year Evaluation

  19. Evaluation of amino acid composition of GEM germplasm Four year evaluation

  20. Highlights of the GEM AA program • DKXL212:N11a-139 Index was significantly higher than B73xMo17 in 4 yr tests. • CHIS740:S1411a-783-2 Met/protein was not significantly different that hi met check and significantly higher than other checks in 4 yr tests • Seven XL370 and XL380 derived lines were not different than high met check in 2 yr evaluations.

  21. Recommendations • Evaluation of hybrids • Selection within GEM “lines” • Development of synthetics for recurrent selection

  22. Divergent selection for amino acid content • Advantages: • Differences are magnified by selection in both directions • Generate unique material to answer biological questions

  23. Intermating of Selections BS31HM C1 Selections (5 ears) BS31HM Selections (5 ears) BS31 BS31HM C2 BS31HM C1 Evaluation of 50 ears Recurrent Selection

  24. Divergent selection for AA Content BS11 BS31

  25. Acknowledgements • Mike Blanco and the GEM team • Merinda Struthers • Funding from USDA-ARS project funds Thanks for your attention!

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