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In Search of New Effective Genes for Crown Rust Resistance in Avena sterilis

Explore the quest for novel genes providing crown rust resistance in Avena sterilis through genetic studies and inoculum research. Check out findings and effective sources of resistance identified for improved oat cultivation.

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In Search of New Effective Genes for Crown Rust Resistance in Avena sterilis

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  1. In Search of New Effective Genes for Crown Rust Resistance in Avena sterilis James Chong and Gang Chen Cereal Research Centre, Agriculture & Agri-Food Canada Winnipeg, MB, Canada R3T 2M9

  2. BREEDING FOR RESISTANCE By the end of 1950s, all deployable sources of resistance from cultivated oat had been overcome in North America (Martens & Dyck 1989).

  3. A large pool of genes for resistance to crown rust was discovered in Avena sterilis,native to the Middle East and North Africa in1960s.

  4. Rapid Adaptation of Puccinia coronata toA. sterilis-derived Resistance Genes Dumont Robert Riel + (Pc38,39) Triple Crown (Pc48) Leggett (Pc68,94) AC Assiniboia Ronald + (Pc38,39,68) Fidler (Pc39) HiFi (Pc91)

  5. 2005 Spring OatCanadian Prairies(Chong) Spring OatND, SD, NE, IA, MN, WI(Carson) Winter OatTX, LA, MS, FL, GA, AL, SC(Carson)

  6. Winter Oat(TX, LA, MS, FL, GA, AL, SC)(Carson) 2005 Spring OatND, SD, NE, IA, MN, WI(Carson)

  7. Avena sterilis Accessions Screened for Crown Rust Reactions in Greenhouse / Field since 1999

  8. Avena sterilis Accession CAV1980 (Algeria)with Adult-plant Resistance Susceptible check Flag leaf

  9. Avena sterilis Accession PI334961 (Israel) immune to Crown Rust Primary leaves Immune to rust

  10. Number of Avena sterilis accessionsSelected for Genetic Studies

  11. Main Objective Identify new effective crown rust resistance sources, particularly those expressed only at the adult-plant stage

  12. Materials & Methods • crosses/backcrosses to a susceptible cultivar. • F1 and BCF1 and progenies raised in growth chambers. • panicles bagged to prevent out-crossing. • rust tests at seedling and adult-plant stages to identify adult-plant resistance.

  13. INOCULUM • greenhouse - individual crown rust isolates/races to identify number of genes involved. • greenhouse and field - composites of crown rust isolates collected from annual surveys of previous year to identify effective gene(s).

  14. Flood at the Glenlea Oat Nursery - 2005

  15. Before After

  16. Harmon x PI 334961 (Israel) - two dom. genes resistant to CR181. - only one was effective to bulk03 and bulk04. - ineffective gene most likely Pc48.

  17. Harmon2 x PI333699 (Israel) - one rec. and one dom. gene resistant to CR181. - dom. gene effective to Bulk03. - within segregating lines, 462 res : 132 sus plants (X2 = 2.444, P = 0.2-0.1).

  18. Harmon2 x CAV1979 (Algeria) - either a single gene (tempPc98) or two tightly linked genes conditioned resistance. - no putative recombinant was found in large number of segregating progenies. - resistant lines had 70MR reaction in New Zealand 2004-05.

  19. Harmon2 x CAV1180 (Algeria) • one rec. and two loosely linked (dom. and p. dom) genes resistant to CR181. • p. dom. gene ineffective to CR223 and bulk04. • rec. gene (pc97temp) resistant to CR225 and bulk04, suppressed by an inhibitor. • pc97temp: 10 MR (Canadian Prairies); 10 R (New Zealand).

  20. AC Morgan x CAV1980 (Algeria) Lines with rec. adult-plant resistance gene (pc99temp) identified by CR225 were resistant in 2004 field test. Dom. gene resistant to CR181 was ineffective in the field.

  21. GENERAL SUMMARY • generally at least two genes present in each accession. • composite of isolates useful for identifying the putative, effective gene(s) in greenhouse tests. • effective adult-plant resistance rare. • gene inhibitors common.

  22. CURRENT EFFECTIVE CROWN RUST RESISTANCE SOURCES • Pc53 – A. sterilis • Pc91 – amagalon material • Pc94 – A. strigosa • Pc96 – A. sativa • Adult-plant resistance from MN841801

  23. FURTHER STUDIES • confirm segregation of genes in field studies. • isolate genes in single-gene lines & gene postulation. • verify effectiveness in multi-locations. • determine allelic/linkage relationships of genes with known Pc genes

  24. ACKNOWLEDGEMENTS Financial support provided in part from: - AAFC Matching Investment Initiative - Agriculture Research Development Initiative - The Quaker Oats Company - The North American Millers Association Technical assistance:Rebecca Dueck and Wayne Mayert Avena sterilis accessions from: - Original collection at AAFC, Winnipeg - National Small Grains Collection, Aberdeen - Plant Gene Resources of Canada, Saskatoon

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