Durable Leaf Rust Durable Leaf Rust Resistance in WheatResistance in Wheat

J. A. KolmerJ. A. Kolmer

USDA-ARS USDA-ARS

Cereal Disease LaboratoryCereal Disease Laboratory

Puccinia triticina - Puccinia triticina - Wheat Leaf RustWheat Leaf Rust

Most common rust Most common rust of wheat in U.S.of wheat in U.S.

Occurs nearly Occurs nearly wherever wheat is wherever wheat is growngrown

Asexual in Asexual in North AmericaNorth America 50-60 races in U.S.50-60 races in U.S. Annual yield lossesAnnual yield losses

Leaf Rust Virulence Dynamics Leaf Rust Virulence Dynamics Kansas - NebraskaKansas - Nebraska

1978 1982 1986 1990 1994 1998 20020

10

20

30

40

50

60

70

80

90

100

Year

Lr1

Lr9

Lr24

Lr26

Lr11

Lr17

Lr10

U.S. Hard Red Spring WheatU.S. Hard Red Spring Wheat Wheaton (1983) Wheaton (1983) Lr10, Lr10, Lr23Lr23, Lr13, , Lr13, Lr34Lr34 +? +? Norm (1992) Norm (1992) Lr1, Lr10, Lr13, Lr1, Lr10, Lr13, Lr16, Lr23Lr16, Lr23, , Lr34Lr34 both highly resistance since releaseboth highly resistance since release

Alsen (2000) Alsen (2000) Lr2a, Lr10, Lr13, Lr23, Lr34 Lr2a, Lr10, Lr13, Lr23, Lr34 R-MRR-MR Knudson (2002) Knudson (2002) Lr3, Lr10, Lr13, Lr3, Lr10, Lr13, Lr16, Lr23, Lr34Lr16, Lr23, Lr34 Briggs (2002) Briggs (2002) Lr13, Lr13, Lr16, Lr30, Lr34Lr16, Lr30, Lr34 Both highly resistantBoth highly resistant Marshall (1982) Marshall (1982) Lr2a, Lr10, Lr13, Lr2a, Lr10, Lr13, Lr34Lr34 Mod. SusceptibleMod. Susceptible

Effective Effective LrLr genes genesin spring wheat cvs.in spring wheat cvs.

AlsenAlsen 2a,10, 13, 23, 342a,10, 13, 23, 34 5 -20 MR5 -20 MR

NormNorm 1, 10, 16, 23, 13, 341, 10, 16, 23, 13, 34 Trace RTrace R

KnudsoKnudsonn

3, 10, 16, 23, 13, 343, 10, 16, 23, 13, 34 Trace RTrace R

TcTcLr16Lr16 50 - 70 MS50 - 70 MS

TcTcLr23Lr23 5 - 10 R MR5 - 10 R MR

TcTcLr34Lr34 5 - 10 M5 - 10 M

ThatchThatcherer

50 - 80 S50 - 80 S

Lr16, Lr23, Lr34 common in spring wheat

South American LandracesSouth American Landraces

Americano 25e (1918) Americano 25e (1918) Lr3, Lr3, Lr16Lr16, , LrX1,LrX1,LrAPRLrAPR

Americano 44d (1918) 1-2 APR genesAmericano 44d (1918) 1-2 APR genes

THBJ FieldTHBJ Field Tc*2/Am. 25e Tc*2/Am. 25e LrAPRLrAPR ;2- 30 MRMS ;2- 30 MRMS Tc*2/Am.44d Tc*2/Am.44d LrAPR LrAPR ;23 20 M;23 20 M Tc*2/Am.44d Tc*2/Am.44d LrAPRLrAPR ;2- 20 ;2- 20

MRMSMRMS

U.S. Soft Red Winter WheatU.S. Soft Red Winter Wheat

Coker 9663 (1996) Coker 9663 (1996) Lr9Lr9, Lr10, Lr14a , Lr10, Lr14a

R-MRR-MR

Pioneer 26R61 (1999) Pioneer 26R61 (1999) Lr13, Lr14b, Lr13, Lr14b, Lr26Lr26

R-MRR-MR

Lr34Lr34 in U.S. Wheat in U.S. Wheat

Hard red spring wheatHard red spring wheat Minnesota Minnesota common 1966-mid 1990scommon 1966-mid 1990s FHB resistant cvs. lack FHB resistant cvs. lack

Lr34Lr34 South Dakota - South Dakota - few cvs. with few cvs. with Lr34Lr34 North Dakota - North Dakota - few cvs. with few cvs. with Lr34Lr34

TcLr34 Tc

Lr34 Lr34 in U.S. Wheatin U.S. Wheat

Soft red winter Soft red winter wheatwheat - old and new - old and new cvs.cvs.

- not present- not present

Hard red winterHard red winter wheat - very rarewheat - very rare

Western spring Western spring wheatwheat - not present - not present

TcLr34 Tc

CSIRO PCR MarkerTip die back

LrLr genes in U.S. Wheat genes in U.S. Wheat Seedling resistance genes Seedling resistance genes - lower ploidy relatives - lower ploidy relatives - common wheat- common wheat Virulent races arise quicklyVirulent races arise quickly Lr9, Lr16, Lr26 - still provide Lr9, Lr16, Lr26 - still provide

some resistancesome resistance Adult Plant GenesAdult Plant Genes Lr34 - not sufficient aloneLr34 - not sufficient alone Lr12 - ineffectiveLr12 - ineffective Lr13 - ineffectiveLr13 - ineffective Lr23 - characteristics of APRLr23 - characteristics of APR

Combinations of Lr34 + Combinations of Lr34 + effective seedling genes effective seedling genes

= best resistance= best resistance

TcLr34 TcLr13 TcLr12 Tc