1. ACRCP-CIMMYT Component Adult plant resistance to wheat rusts
Ravi P. Singh
Sybil A. Herrera-Foessel
Caixia Lan
Julio Huerta-Espino
Progress up to Sept, 2011

2. Objectives
Long-term control of rust diseases through durable resistance
Enhancing wheat productivity (higher yield potential, APR to all three rusts, yield stability, WUE, etc.) and end-use quality
Pre-emptive phenotyping of wheat (Ug99, YR, LR) and barley (YR)

3. Outputs
Genomic locations of APR genes
Molecular markers for APR genes
Relevant germplasm with high levels of APR
Scientific information
Scientific capacity
Enhanced partnership
Research advocacy

4. Characterization and mapping of two slow rusting resistance genes
Lr68 SOURCE: PARULA (CIMMYT wheat)1
Lr67/Yr46 SOURCE: RL6077 (source of resistance in RL6077- an accession from Pakistan)2
1 Not published
2 Hiebert et al 2010, Herrera-Foessel et al 2011 TAG

5. Lr68: a new leaf rust slow rusting resistance gene
Apav
Lr67
Lr68
Lr46
Lr34
Avocet-YrA
LR response Obregon

6. Genetic linkage map of Lr68 and markers in chromosome 7BL based on Apav x Arula mapping population
gwm577
wmc273
barc182
wmc232
Cfa2257
csGS
7BLNLRR
Psy1-1
Lr68
gwm146
4.8
3.4
0.7
0.1
0.5
0.3
0.4
0.6
Co-dominant CAPS marker 7BLNLRR developed by E. Lagudah associated with Lr68 at 0.7 cM is useful for tagging Lr68

7. γ-irradiation induced deletion stock identified for Lr68 (+/- Lr14b)
Response
Origin
Flanking markers
Field (MBJ/SP)
Greenhouse 2-leaf stage (TCT/QB)
M3 line
Different M1
7BLNRR
Psy1-1
gwm146
Presence of Lr68
Presence of Lr14b 4 A
Intact
S (no Lr68)
R (Lr14b) 7 B
Deleted
S (no Lr14b) 23 C 25 D 33 F 34 39 G 43 H

8. Effect of Lr67/Yr46 on stem rust resistance
Stem rust evaluation in Obregon
Example of Non-Sr2 based high level of APR

9. Populations for mapping new slow rusting resistance genes
Sujata, New Pusa 876, Kundan, Ponta Grossa and Kenya Kongoni
Old wheat lines from India, Brazil and Kenya
Show LTN and slow rusting resistance to leaf rust and yellow rust
Lack Lr34 (based on gene based marker) and Lr46 (allelism test)
Mapping populations developed with crosses with susceptible parent Avocet, and with Lr46 tester.
F5 RIL populations from simple crosses and BC1 with Avocet-YrA phenotyped for LR and YR in Toluca/Batan 2011.
Frequency distributions of RILs indicate complex inheritance of resistance (between 2-5 minor genes depending on disease and parent)
Sujata also carries a seedling effective YR gene (infection type 23 on 0-9 Scale)
Phenotyping in Obregon for LR and DArT marker analysis is planned

10. Toluca stripe rust evaluations 2011
Avocet Ponta Sujata NP Kenya Kundan
Grossa Kongoni

11. Avocet/ Francolin F5 population
Francolin released or in advanced stage for release in several countries
Complex inheritance for both LR and YR including Lr46/Yr29 and Sr2/Yr30
Seedling leaf rust resistance gene that interacts with other genes in field (Lr16?, linked markers absent)
Seedling stripe rust resistance genes (one or two?) that interact with other genes in field
Between 3-5 genes conferred resistance to LR & YR

12. Interaction between APR Lr46/Yr29 and seedling gene LrF for leaf rust and stripe rust resistance in Avocet/Francolin

13. Interaction between APR Lr46/Yr29 and seedling gene YrF for leaf rust and stripe rust resistance for Avocet/Francolin F5 population

14. Babax/Lr42//Babax = RSM Norman 2008
High-yielding CIMMYT line derived from the cross of a Kansas germplasm with Lr42 from T. tauschii .
Some selections carry high level of APR to yellow rust.
Two white grained single backcross derived lines, Quaiu and Babax/Lr42//Babax*2/3/Kuruku, were crossed with Avocet and F5 RILs (198 for each cross) developed.
Populations phenotyped for LR and YR for two years in Mexico.
Complex inheritance for LR (including Lr42) and YR.
DArT and SSR analyses to identify genomic regions associated with resistance.

15. Avocet x Quaiu F5 population – QTLs for stripe rust resistance
LOD
LOD
LOD
Chr-1B (Yr 29)
Chr-2D (Novel ?)
Chr-3B (Novel ?)
Analysis with ICImapping software
Bhoja Basnet PhD student

16. Avocet x Quaiu F5 population – QTLs for leaf rust resistance
LOD
Chr-1B (Lr46)
LOD
Chr-1D (Lr42)
LOD
Chr-3D (Novel ?)
Bhoja Basnet PhD student

17. Interaction of Lr46, Lr68 and Sr2 in ‘Avocet’ x ‘Weebill 1/Brambling’ F5 population for leaf rust resistance using linked markers (Cd. Obregon )
Source:Violeta Calvo, BSc student

18. SSR markers, 520 in total, screened on parents of different populations
Bread wheat Durum wheat
Avocet-YrA x Francolin Atil*2/Local red x Atil C2000
Avocet-YrA x Fret*2/Tuk/Fret Atil*2/Local red x Quetru
Avocet-YrA x Weebill 1*2/Brambling Atil C2000 x Planeta
Avocet-YrA x Avocet/Lalb/Mono
Avocet x Ponta Grossa
Avocet x Sujata
Avocet x NP876
Avocet x Kenya Kongoni
Avocet x Kundan
Avocet x RL6077 (SR)

19. Polymorphic SSR markers between Avocet and six resistant parents of RIL populations
No. of SSR markers
Polymorphism between parents
Polymorphism (%)
FRANCOLIN
520
295
0.567
PONTA GROSSA 1
260
0.500
MUTATED C-306
261
0.502
NEW PUSA 876
244
0.469
KENYA KONGONI
226
0.435
DL153-2
253
0.487

20. Summary of stripe rust evaluations (Toluca 2011) for 1160 Barley accessions from Australia
Severity range SA WA
QLD
PBI-Lida
%YR
% lines
0-15 3 39 14 59
20-40 8 23 24 26
50-100 89 38 62 16
Number lines
346
317
231 90
Missing entries, lines with mixed response were not included, Mean value of Replicated lines (WA) were used for WA wh
ere some lines were replicated

21. Acknowledgements
Our collaborators in Australia (Australian Cereal Rust Control Program)
GRDC, Australia
Global Wheat Program, CIMMYT, Mexico