Population genetics of Puccinia triticina in North America Maria E. Ordoñez James A. Kolmer USDA-ARS-Cereal Disease Laboratory University of Minnesota St. Paul, MN

P. triticina collections 89 isolates from U.S isolates from the U.S. 1980’s 1990’s 20 isolates from Canada mid 1990’s 5 isolates from durum wheat from Mexico 2003 Total = 151

Virulence phenotypes on 20 Thatcher near-isogenic lines Molecular genotypes with 23 simple sequence repeat markers (SSR) 89 virulence phenotypes 73 SSR genotypes

Diversity of virulence and SSR genotypes BLFPNDP-17TM-17TKMT’SDurum No. isolates No. races No. SSR genotype Diversity index I

NJ tree of clone corrected virulence phenotypes B FPN DL S P-17 T’ TK C M TM- 17 Groups based on Vir/Avir to Lr1, Lr2a, Lr2c, Lr3, Lr3bg, Lr17 and Lr28

Durum FPND B P-17 S L TKM NJ tree of clone corrected SSR genetic distances T’ TM-17 9 groups based on SSR and virulence to Lr1, Lr2a, Lr2c, Lr3, Lr3bg, Lr17 and Lr28

Distribution of SSR allelic variation, diversity index, heterozygosity F ST R ST Among pop.21%41% Within pop.79%59% I = Ho = He =

Unrooted NJ dendrogram based on pair-wise F ST values for SSR genotypes Significant difference (p<0.05) FPND - P-17 TKM - TM-17 T’ - all S - all Durum - all

Summary  Several groups of P. triticina found in NA based on virulence phenotype and SSR genotype  Difference in virulence and SSR genotypes suggest introduction or migration of a new race: TM-17 and other T, K, M T’ and other T races  Similar virulence and SSR genotype suggest mutation and selection: T low on Lr14a and Lr20, and T high on Lr14a and Lr20 T, M, K races P, F races  P-17 and other P races different groups  Durum isolates genetically different from common wheat isolates