Borlaug Global Rust Initiative Technical Workshop – 2014 Session: “Rust Resistance in Tetraploids” Ciudad Obregon, March 23, 2014

Advances in Breeding for Resistance to Stem Rust

Caused by Ug99 and Ethiopian Pgt Races in Durum Wheat

Ayele Badebo DZARC – EARO, Ethiopia

Karim Ammar, Abeyo Bekele, Alexandro Loladze, Susanne Dreisigacker, Roberto-Javier Peña & Masahiro Kishii Global Wheat Program - CIMMYT

Stem Rust on Durum Wheat Specificity of the pathogen and current presence

�  Ug99+variants ■  Present in Kenya, Ethiopia, Yemen, Iran

■  Widespread resistance in most durum germplasm groups

�  Ethiopian races, pre-dating Ug99 ■  Not as well characterized ■  Sr13+Sr9e combined virulence (Olivera et al. 2010)

■  Very little resistance (5%) in all germplasm groups worldwide (Olivera et al. 2010)

■  Confined to Ethiopia?, Sr13 virulence present in Turkey

Stem Rust on Durum Wheat Durum areas threatened by the “Ethiopian” races:

�  Durum areas of Central India (1.0-1.5 million ha) ■  Through Yemen, most likely path as confirmed by migration of Ug99 ■  Stem rust (less virulent races) already endemic in the region

�  Turkey, North-Africa, Middle-East (>5 million ha) ■  Less likely dissemination path, but cannot

be ignored ■  Sr13-virulence present in Turkey ■  Durum critical in these areas ■  Historically favorable climatic conditions for

the development of stem rust epidemics David Hodson et al. 2008

�  Threat likely to increase with warming temperatures earlier in the cropping seasons as predicted by climate change scenarios

Breeding for Stem Rust Resistance in Durum Wheat Screening in Njoro-Kenya vs. Debre Zeit-Ethiopia

y = 0.9729x + 22.67R2 = 0.223

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SR reading KENYA

SR re

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PIA

Breeding for Stem Rust Resistance in Durum Wheat The basis of our strategy

�  Establishment of bi-annual screening program in Ethiopian “hot-spot” ■  Hosted by the Debre Zeit Ag. Res. Center ■  Artificial inoculation with mixture of relevant races (Ethiopian races + Ug99) ■  Screening of 1000s of lines annually:

•  Resistance sources discovery for crossing •  Resistance confirmation in new advanced lines •  Genetic studies for resistance characterization

Photos: Dr. Ayele Badebo

Breeding for Stem Rust Resistance in Durum Wheat Rare resistance to start with in 2009… but enough to work with

50 – 70 S

80 – 100s

278

64

71.3

16.4

Reaction Class

Number of Lines

Percent of Total

10 MR – 20 MRMS 12 3.1 30 MR – 40 MSS 36 9.3

Data from Debre Zeit, off-season 2009

390 Elite Lines

Breeding for Stem Rust Resistance in Durum Wheat Emphasis in CIMMYT crossing program

296 456

268 219

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2009 2010 2011 2012

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Crosses made for Stem Rust Resistance 2009 - 2012

Stem Rust Crosses

20 – 46% of program’s crossing effort

�  Resistance Sources ■  CIMMYT Elite ■  European germplasm ■  North-American

germplasm ■  ICARDA germplasm ■  Genetic resources ■  Stocks with marked

genes (MAS)

Breeding for Stem Rust Resistance in Durum Wheat Selection stream: parallel selection Ethiopia/Mexico of new fixed lines

F3 Toluca

F2 Obregon

F6 PYT Obregon

F5 Toluca/Batan

F4 Obregon

F6 Off season Debre Zeit

F7 HR Batan

F7 Main season Debre Zeit

F8 Rep YT Obregon

F8 Off season Debre Zeit

Distribution Globally

Release Ethiopia

Selection for LR, YR, agronomic type, earliness and grain-fill

MEXICO: Selection for yield, drought tolerance, quality

ETHIOPIA: Selection for Stem Rust resistance

Breeding for Stem Rust Resistance in Durum Wheat Significant increase in resistant germplasm distributed globally

Number % Number % Number % Number %

Reaction Group of Lines Total of Lines Total of Lines Total of Lines Total

Resistant 20 13.2 5 3.3 17 10.7 26 12.0

Moderately Resistant 5 3.3 17 11.3 44 27.7 60 27.8

Useful for Stem Rust 25 16.4 22 14.6 61 38.4 86 39.8

Moderately Susceptible 12 7.9 19 12.7 5 3.1 2 0.9

Susceptible 115 75.7 109 72.7 93 58.5 128 59.3

N = 152 N = 150 N = 159 N = 216

43 IDYN+IDSN 44 IDYN+IDSN 45 IDYN+IDSN 46 IDYN+IDSN

Distributed 2011 Distributed 2012 Distributed 2013 Distributed 20142009: 3.1%

Breeding for Stem Rust Resistance in Durum Wheat Significant increase in resistant germplasm distributed globally while maintaining agronomic performance

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Grain Yield as % of Check JUPARE C2001

Yield Distribution under FULL IRRIGATION within germplasm distributed in 2013 and 2014 International Nurseries

ALL (N=304)

Stem Rust R/MR (N=124)

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Grain Yield as % of Check JUPARE C2001

Yield Distribution under DROUGHT within germplasm distributed in 2013 and 2014 International Nurseries

ALL (N=291)

Stem Rust R/MR (N=115)

�  Stem Rust Resistant lines have similar distribution than other lines ■  Yield Potential ■  Drought Tolerance ■  Quality attributes (gluten strength & yellow color)

Breeding for Stem Rust Resistance in Durum Wheat Stacking alien genes of resistance via MAS

Sr25/Lr19 7AL L. ponticum Durum w heat 1 PsyA1+PsyER4 Co-dominantFull phenotypic expression, routine use in parent characterization and MAS

cfa2123 Co-dominant

csKP81 Co-dominant

InheritancePhenotypic Validation and use in program

Sr22Full phenotypic expression, routine use in parent characterization and MAS

Location OriginSource

Originally Used

7AL T. boeticum Bread w heat

GeneMarker Designation

1: Transferred to durum by Dr. Adam Lukashewski, U.C. Riverside

Sr22 (cfa2123, cfa2019)

Sr25 (PSY1-EF2_ER4)

Photos: Susanne Dreisigacker

Breeding for Stem Rust Resistance in Durum Wheat Sr22 and Sr25 loci tightly linked , essentially inherited together, attempt at better gene stewardship…

Xgpw2242 -8.2 Xfba243 0.0 Xfba17 Xgpw4130 13.0 Xcfd62 18.7 Xfba231 22.4 XEF1R 33.9 Xfba127 38.9 Xfba109 58.4 Xbcd1438 59.4 Xgpw3201 65.3 Xgpw3234 76.2 Xfbb222 86.8 Xcfa2056 97.8 Xfbb79 98.9 Xfba71 99.5 Xfbb366 106.8 Xgpw3208 125.4 Xcfd6 129.5 Xgpw7313 136.1 Xpsr165 136.6 Xwmc182 137.7 Xpsp3050 138.4 Xcfa2110 147.5 XksuA5 168.5 Xbc9O10 169.6 Xglk478 174.5 XksuG12 178.2 Xcfa2123 193.3 Xfba69 198.7 Xpsp3094 Xgpw2252 210.6 Xtam51 219.9 Xcfa2019 224.0 Xcfa2293 232.4 XksuD2 232.8 Xfba350 244.7 Xwg232.1 253.6 Xwg232.2 253.8 Xcfa2040 256.2 XksuH9 267.5

7AL-1-0.39-0.71

7AL-18-0.9-1

Sr22 (cfa2123, cfa2019)

Sr25 (PSY1-EF2_ER4)

Chr. 7A (Courtot x C.S.)

DWSr22 x Elite 1

F1Sr22

DWSr25 x Elite 2

F1Sr25 X

Double-Cross Population

F2

F6

F8

Testing SR

Testing SR Yield, Drought

Quality

MAS

Breeding for Stem Rust Resistance in Durum Wheat Advanced lines with linked Sr22+Sr25

�  GISH of L. Ponticum segment ■  Telomeric

�  GISH of T. Boeticum segment ■  Not yet available

Photos: Masahiro Kishii

Breeding for Stem Rust Resistance in Durum Wheat Advanced lines with linked Sr22+Sr25: Characteristics

�  Confirmed homozygocity for both genes ■  Markers stably homozygous in F6 – F8 head-rows ■  Stably resistant over 2-3 seasons at Debre Zeit

�  Improved quality parameters ■  Better gluten strength than most local cultivars ■  Significantly higher yellow color than local cultivars

�  Variable yield performance and drought tolerance ■  Obregon: some yield penalty due to lower kernel size ■  Ethiopia: under evaluation ■  Second round breeding started!!

CIMMYT – DZARC Joint Breeding Effort for Stem Rust Resistance in Durum Wheat: Conclusions

�  Strategy of parallel Selection Mexico/Ethiopia has been successful ■  Significant progress in frequency of SR

resistant or moderately resistant lines in CIMMYT outgoing germplasm

■  Useful variability for yield potential, drought tolerance and quality maintained in new resistant germplasm

�  Debre Zeit phenotyping platform has been key! ■  Testing facilities have been enhanced, effort

needs sustaining

�  MAS with gene stewardship in mind provided valuable germplasm ■  If not usable for cultivar release, provides useful

parental stocks for further breeding

Stem Rust Resistance in Durum Wheat Research efforts to provide information and markers for breeding

�  Association Mapping of Stem Rusts resistance ■  Beachell-Borlaug scholar Tesfaye Dugo Letta ■  Led y Prof. Tuberosa team, Univ. Bologna, Italy ■  Results from adult plant reaction and seedling published

(Letta et al., TAG, 2013; Letta et al., Plant Genome, 2014)

�  Mapping of Stem Rust Resistance from Boohai ■  Beachell-Borlaug scholar Tesfaye Dugo Letta ■  Led y Prof. Tuberosa team, Univ. Bologna, Italy ■  Phenotyping done, mapping in process

�  Mapping of Stem Rust Resistance from COCORIT ■  Collaboration with Dr. Curtis Pozniak, Univ. Saskatchewan ■  Preliminary results presented, manuscript in progress