In Search of New Effective Genes for Crown

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 R 3 T 2 M 9

BREEDING FOR RESISTANCE By the end of 1950 s, 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 in 1960 s.

Rapid Adaptation of Puccinia coronata to A. sterilis-derived Resistance Genes Dumont Robert Riel + (Pc 38, 39) Fidler (Pc 39) Triple Crown (Pc 48) AC Assiniboia Ronald + (Pc 38, 39, 68) Leggett (Pc 68, 94) Hi. Fi (Pc 91)

2005 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)

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

Avena sterilis Accession CAV 1980 (Algeria) with Adult-plant Resistance Susceptible check Flag leaf

Avena sterilis Accession PI 334961 (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 Israel 10 Lebanon 1 Africa Algeria 3 Europe Portugal 1 Italy 1

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. • F 1 and BCF 1 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.

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).

Flood at the Glenlea Oat Nursery - 2005

Before After

Harmon x PI 334961 (Israel) No. of F 3 lines Inoculum Res Seg (IT) Sus Ratio X 2 P CR 181 17 23 (0 IT) 2 7: 8: 1 0. 4422 0. 7 -0. 5 Bulk 03 11 21 10 1: 2: 1 0. 0476 0. 9 -0. 8 Bulk 04 11 21 10 1: 2: 1 0. 0476 0. 9 -0. 8 - two dom. genes resistant to CR 181. - only one was effective to bulk 03 and bulk 04. - ineffective gene most likely Pc 48.

Harmon 2 x PI 333699 (Israel) No. of plants or families BCF 1 Resistant (IT) Sus Ratio X 2 P 34 (0) 11 3: 1 0. 0074 0. 95 -0. 90 Segregating (IT) Sus - CR 181 34 (0) 6 (; -; 1) 5 6: 1: 1 0. 0963 0. 98 -0. 95 - Bulk 03 24 (0) 21 1: 1 0. 2 0. 70 -0. 50 - CR 181 BCF 2 - one rec. and one dom. gene resistant to CR 181. - dom. gene effective to Bulk 03. - within segregating lines, 462 res : 132 sus plants (X 2 = 2. 444, P = 0. 2 -0. 1).

Harmon 2 x CAV 1979 (Algeria) No. of families Isolate Segregating (IT) Sus Ratio X 2 P CR 181 43 (0; -; 1 -) 57 1: 1 0. 2596 0. 70 -0. 50 CR 240 43 (0 -; ) 57 1: 1 CR 205 43 (0; -; 11+) 57 1: 1 CR 192 43 (0; -; 1 -) 57 1: 1 CR 225 43 (; 1 -12) 57 1: 1 CR 223 43 (; 1 -11+) 57 1: 1 - either a single gene (temp. Pc 98) or two tightly linked genes conditioned resistance. - no putative recombinant was found in large number of segregating progenies. - resistant lines had 70 MR reaction in New Zealand 2004 -05.

Harmon 2 x CAV 1180 (Algeria) No. of plants or families BCF 1 Resistant (IT) Sus Ratio X 2 P 52 (; ) 10 (; 11+) 33 3: 1 4. 8034 <0. 05 Segregating (IT) Sus - CR 181 71 (0; -; 1) 22 7: 1 10. 5822 <0. 01 - CR 223 61 (0; -; 1) 32 3: 1 4. 3907 0. 05 -0. 02 - Bulk 04 61 (0; -; 1) 32 3: 1 4. 3907 0. 05 -0. 02 - CR 225 40 (; -; 1) 52 1: 1 1. 5652 0. 30 -0. 20 - CR 13 23 (; -; 1) 71 1: 3 0. 0141 0. 90 - CR 181 BCF 2 - one rec. and two loosely linked (dom. and p. dom) genes resistant to CR 181. - p. dom. gene ineffective to CR 223 and bulk 04. - rec. gene (pc 97 temp) resistant to CR 225 and bulk 04, suppressed by an inhibitor. - pc 97 temp: 10 MR (Canadian Prairies); 10 R (New Zealand).

AC Morgan x CAV 1980 (Algeria) No. of F 2 plants & F 3 lines Res (IT) Seg Sus Ratio X 2 P 0 … 127 32 (; 1 -; 2) … 95 1: 3 0. 0026 0. 98 -0. 95 35 56 32 1: 2: 1 1. 1301 0. 70 -0. 50 F 3 seedlings 26 70 31 1: 2: 1 1. 7244 0. 50 -0. 30 2004 field - F 3 34 (0 -20 RMR) 1: 3 0. 2125 0. 70 -0. 50 CR 225 F 2 seedlings F 2 adults F 3 lines CR 181 93 Lines with rec. adult-plant resistance gene (pc 99 temp) identified by CR 225 were resistant in 2004 field test. Dom. gene resistant to CR 181 was ineffective in the field.

Summary of Crown Rust Resistance Genes Identified Accession & origin Field No. of genes* effective reaction identified Comments CAV 1339 tr. MSS 2 (D, r) PI 333463 0 2 (D, r) 1 (r) PI 333699 0 2 (D, r) 1 (D) PI 334961 0 -tr. S 2 (D) 1 (D) PI 374915 2 MRMS-10 MR 2 (D) 1 (D) PI 375695 tr. MRMS-5 MR 1 (r) PI 378740 10 RMR-tr. S 2 + 1(r) PI 404589 5 RMR-tr. S 1 (D) 1(D) inhibitor 2(D) 1(r) 1(D) 1(r) inhibitor of 'r‘; Field (10 MR) Israel Field (10 RMR) Lebanon CAV 1180 *D = dominant or near-dominant, r = recessive or near-recessive.

Summary of Crown Rust Resistance Genes Identified (cont. ) Accession Field & origin reaction No. of genes Identified Effective 2 (D, r) 1 (D) Comments Algeria CAV 1975 CAV 1979 1? (D-r) Field ( MR) CAV 1980 5 RMR 2 (D, APR) 1 (APR) APR field (0 -5 RMR) 1 (D), 2 (linked r) 1 (r) inhibitor of 'r' 60 R 1 (D) 2(r) 1 (D) 1(r) tr. R-5 RMR 3? (0, ; 1, 2 ITs) 1+ ? Portugal IB 2433 Italy CAV 2568 PI 497690 (MN 788788, Amagalon) *D = dominant or near-dominant, r = recessive or near-recessive progenies mostly sterile inhibitor present ?

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.

CURRENT EFFECTIVE CROWN RUST RESISTANCE SOURCES • Pc 53 – A. sterilis • Pc 91 – amagalon material • Pc 94 – A. strigosa • Pc 96 – A. sativa • Adult-plant resistance from MN 841801

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

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