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

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).

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

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

Spring Oat Canadian Prairies (Chong) Spring Oat ND, SD, NE, IA, MN, WI (Carson) Winter Oat TX, LA, MS, FL, GA, AL, SC (Carson) 2005

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

Country of origin No. of accessions Middle East Israel, Iran, Libya … 3200 Africa Algeria, Ethiopia, Tunisia … 200 Europe Spain, Turkey, Morocco … 640 Avena sterilis Accessions Screened for Crown Rust Reactions in Greenhouse / Field since 1999

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

Avena sterilis Accession PI (Israel) immune to Crown Rust Primary leaves Immune to rust

Number of Avena sterilis accessions Selected for Genetic Studies Country of origin Number Middle East Israel10 Lebanon1 Africa Algeria3 Europe Portugal1 Italy1

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

Materials & Methods crosses/backcrosses to a susceptible cultivar.crosses/backcrosses to a susceptible cultivar. F 1 and BCF 1 and progenies raised in growth chambers.F 1 and BCF 1 and progenies raised in growth chambers. panicles bagged to prevent out-crossing.panicles bagged to prevent out-crossing. rust tests at seedling and adult-plant stages to identify adult-plant resistance.rust tests at seedling and adult-plant stages to identify adult-plant resistance.

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

Flood at the Glenlea Oat Nursery

BeforeAfter

Harmon x PI (Israel) No. of F 3 lines InoculumRes Seg (IT) SusRatio X2X2X2X2P CR (0 IT) 27:8: Bulk :2: Bulk :2: two dom. genes resistant to CR only one was effective to bulk03 and bulk04. - ineffective gene most likely Pc48.

Harmon 2 x PI (Israel) No. of plants or families BCF 1 Resistant (IT) SusRatio X2X2X2X2P - CR (0) 113: BCF 2 Segregating (IT) Sus - CR (0) 6 (;-;1) 56:1: Bulk03 24 (0) 211: one rec. and one dom. gene resistant to CR dom. gene effective to Bulk03. - within segregating lines, 462 res : 132 sus plants (X 2 = 2.444, P = ).

Harmon 2 x CAV1979 (Algeria) No. of families Isolate Segregating (IT) SusRatioX2P CR (0;-;1-) 571: CR (0-;) 571:1 CR (0;-;11+) 571:1 CR (0;-;1-) 571:1 CR (;1-12) 571:1 CR (;1-11+) 571:1 - 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

Harmon 2 x CAV1180 (Algeria) No. of plants or families BCF 1 BCF 1 Resistant (IT) SusRatio X2X2X2X2P - CR (;) 10 (;11+) 333: <0.05 BCF 2 Segregating (IT) Sus - CR (0;-;1) 227: < CR (0;-;1) 323: Bulk04 61 (0;-;1) 323: CR (;-;1) 521: CR13 23 (;-;1) 711: one rec. and two loosely linked (dom. and p. dom) genes resistant to CR 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).

AC Morgan x CAV1980 (Algeria) No. of F 2 plants & F 3 lines Res (IT) SegSusRatioX2P CR225 F 2 seedlings F 2 seedlings0…127 F 2 adults F 2 adults 32 (;1-;2) …951: F 3 lines F 3 lines :2: CR181 F 3 seedlings F 3 seedlings :2: field - F 3 34 (0-20 RMR) : 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.

Summary of Crown Rust Resistance Genes Identified Accession & Field No. of genes* originreactionidentifiedeffectiveComments Israel CAV1339trMSS 2 (D, r) PI (r) PI (D, r) 1 (D) PI trS 2 (D) 1 (D) PI MRMS-10MR 2 (D) 1 (D) Field (10 RMR) PI375695trMRMS-5MR 1 (r) PI RMR-trS 2 + 1(r) PI RMR-trS 1 (D) 1(D)inhibitor Lebanon CAV1180 2(D) 1(r) 1(D) 1(r) inhibitor of 'r‘; Field (10MR) *D = dominant or near-dominant, r = recessive or near-recessive.

Summary of Crown Rust Resistance Genes Identified (cont.) AccessionField No. of genes & origin reactionIdentifiedEffectiveComments Algeria CAV (D, r) 1 (D) CAV1979 1? (D-r) Field ( MR) CAV19805RMR 2 (D, APR) 1 (APR) APR field (0-5RMR) Portugal IB (D), 2 (linked r) 1 (r) inhibitor of 'r' Italy CAV256860R 1 (D) 2(r) 1 (D) 1(r) PI497690trR-5RMR 3?(0, ;1, 2 ITs) 1+ ? progenies mostly sterile (MN788788, Amagalon) inhibitor present ? *D = dominant or near-dominant, r = recessive or near-recessive

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

CURRENT EFFECTIVE CROWN RUST RESISTANCE SOURCES Pc53 – A. sterilisPc53 – A. sterilis Pc91 – amagalon materialPc91 – amagalon material Pc94 – A. strigosaPc94 – A. strigosa Pc96 – A. sativaPc96 – A. sativa Adult-plant resistance from MN841801Adult-plant resistance from MN841801

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

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 ACKNOWLEDGEMENTS