Resistance to Race TTKSK of Puccinia graminis f. sp. tritici in Emmer ...

RESEARCH 

Resistance to Race TTKSK of Puccinia 

graminis f. sp. tritici in Emmer Wheat 

Pablo D. Olivera, Ayele Badebo, Steven S. Xu, Daryl L. Klindworth, and Yue Jin* 

ABSTRACT 

Race TTKSK (Ug99) of Puccinia graminis f. sp. 

tritici is a serious threat to wheat production 

worldwide because of its wide virulence on 

many cultivars and rapid spread. Emmer wheat 

[Triticum turgidum L. subsp. dicoccon (Schrank) 

Thell.] is known to be a source of resistance 

to stem rust but has not been evaluated 

against race TTKSK. In attempts to identify 

and characterize stem rust resistance genes 

effective against race TTKSK at the seedling 

stage, we evaluated 359 accessions of emmer 

wheat with race TTKSK and other races with 

broad virulence. A high frequency (31.8%) of 

accessions were resistant to TTKSK at the 

seedling stage with low infection types ranging 

from 2 = to 2 + . Thirty-seven accessions exhibited 

a resistant to moderately resistant response in 

Debre Zeit, Ethiopia, and St. Paul, MN, nurseries 

in 2010 and 2011. Studies were conducted to 

determine the inheritance of TTKSK resistance 

in fi ve accessions at the seedling stage. Results 

from evaluating F 2 and F 2:3 generations revealed 

that resistance was conferred by single genes. 

One additional gene effective against race 

TTTTF was identifi ed in the resistant parents. 

Results from this study indicated that emmer 

wheat is a source of resistance to race TTKSK 

and may contribute novel resistance genes. 

Since emmer wheat shares the same genome as 

durum [Triticum turgidum subsp. durum (Desf.) 

Husn.] wheat and is in cultivated form, resistance 

genes should be easily transferred to durum 

wheat by conventional breeding approaches. 

P.D. Olivera, Department of Plant Pathology, University of Minnesota, 

St. Paul, MN 55108; A. Badebo, Ethiopian Institute of Agricultural 

Research (EIAR), Debre Zeit, Ethiopia; S.S. Xu and D.L. Klindworth, 

USDA-ARS, Northern Crop Science Laboratory, Fargo, ND 58108; 

Y. Jin, Department of Plant Pathology, University of Minnesota, St. 

Paul, MN, and USDA-ARS, Cereal Disease Laboratory, St. Paul, MN 

51108. Received 7 Dec. 2011. *Corresponding author: (Yue.Jin@ars. 

usda.gov). 

Abbreviations: APR, adult plant resistance; IT, infection type; NSGC, 

National Small Grain Collection. 

Stem rust, caused by Puccinia graminis Pers.:Pers. f. sp. tritici 

Eriks. and E. Henn., is one of the most destructive diseases of 

durum and common or bread wheat (Triticum aestivum L.) worldwide. 

In particular, a group of TTKS (or Ug99) related races possess 

broad virulence to wheat cultivars worldwide, and only a few 

genes in adapted cultivars are eff ective against these races (Jin and 

Singh, 2006; Jin et al., 2007; Pretorius et al., 2011). Since fi rst 

reported in 1999 (Pretorius et al., 2000), TTKSK and its variants 

have been found throughout eastern and southern Africa (Jin et 

al., 2008; Singh et al., 2011; Visser et al., 2010; Wanyera et al., 

2006; Wolday et al., 2011) and Iran (Nazari et al., 2009). The lack 

of resistance in adapted germplasm coupled with its rapid evolution 

and spread urgently requires the identifi cation and introgression 

of eff ective resistance genes into adapted wheat. Wild and 

cultivated relatives of wheat are known to be a good source of 

stem rust resistance genes. A number of resistance genes derived 

from wild relatives of wheat appeared to be more eff ective against 

the TTKS races of P. graminis f. sp. tritici than genes of wheat 

origin (Jin et al., 2007; Singh et al., 2006). However, the use of 

Published in Crop Sci. 52:2234–2242 (2012). 

doi: 10.2135/cropsci2011.12.0645 

© Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA 

All rights reserved. No part of this periodical may be reproduced or transmitted in any 

form or by any means, electronic or mechanical, including photocopying, recording, 

or any information storage and retrieval system, without permission in writing from 

the publisher. Permission for printing and for reprinting the material contained herein 

has been obtained by the publisher. 

2234 WWW.CROPS.ORG CROP SCIENCE, VOL. 52, SEPTEMBER–OCTOBER 2012

esistance from cultivated wheat relatives may be preferred 

to hasten the introgression process. 

Emmer wheat is a tetraploid (2n = 4x = 28, genome 

AABB) ancient hulled wheat. It is the oldest cultivated 

wheat (Kuckuck, 1970), and it is still grown in Ethiopia 

(Beteselassie et al., 2007), the Middle East, and Europe 

(Hammer and Perrino, 1984; Stallknecht et al., 1996). 

Emmer wheat is known to be a good source of resistance 

to wheat diseases (Gras, 1980; Oliver et al., 2008), pests 

(Liu et al., 2005), and environmental stresses (Sayed, 

1985). Emmer wheat has contributed important genes for 

stem rust resistance, including Sr2 from Yaroslav emmer 

(McFadden, 1930) and Sr13 and Sr14 from Khapli (CItr 

4013) (Heermann and Stoa, 1956). Reaction of emmer 

wheat to the recently emerged race TTKSK and its variants 

has not been characterized. The high variability observed 

in emmer wheat for agronomic and quality traits (Damania 

et al., 1992; Pfl üger et al., 2001; Sayed, 1985) opens the 

possibility for the identifi cation of new and diverse stem 

rust resistance genes if germplasm collections are extensively 

screened. In addition, since emmer and durum wheat have 

the same genome constitution and share complete genomic 

compatibility (Yanchenko, 1985), resistance to stem rust 

from emmer could be easily introgressed into durum wheat. 

To identify novel stem rust resistance genes eff ective against 

TTKSK and its variants, we evaluated emmer wheat for 

resistance to stem rust races with broad virulence at the 

seedling and adult stage and conducted preliminary studies 

on the genetic basis of stem rust resistance. 

MATERIALS AND METHODS 

Germplasm 

A total of 359 accessions of emmer wheat deposited at the USDA- 

ARS National Small Grain Collection (NSGC) (Aberdeen, ID) 

were evaluated in this study. Six emmer wheat accessions were 

selected for an inheritance and allelism study based on their reaction 

to races TTKSK, TRTTF, and TTTTF. Five accessions (PI 

101971, PI 193883, PI 217640, PI 298582, and PI 319869) were 

used as the resistant parents, and one accession (CItr 7966) was 

used as the susceptible parent. In total, 11 crosses were developed 

to investigate the number of genes conferring resistance or 

to determine the relationship between resistant parents. The F 1 

plants were grown and selfed to produce F 2 populations. Individual 

F 2 plants were then selfed to produce F 2:3 families. 

Inoculation, Incubation, 

and Disease Assessment 

Seedling Evaluations 

The entire emmer wheat collection of the NSGC was evaluated 

for reaction to three P. graminis f. sp. tritici races with broad virulence 

and diff erent geographic origin: TTKSK (Kenya), TRTTF 

(Yemen), and TTTTF (United States). Accessions exhibiting resistance 

to race TTKSK were further characterized for their reaction 

to six additional U.S. races (TPMKC, RKQQC, RCRSC, 

QTHJC, QCCLC, and MCCFC). The race designation is based 

on the letter code nomenclature system (Roelfs and Martens, 

1988; Roelfs et al., 1993), modifi ed to further delineate races in 

the TTKS group (Jin et al., 2008). Information about the stem 

rust isolates used in the disease phenotyping tests is summarized 

in Table 1. Five seedlings per accession were inoculated on fully 

expanded primary leaves 8 to 9 d after planting. Experimental 

procedures in inoculation and disease assessment were described 

by Jin et al. (2007). Wheat cultivar McNair 701 (Cltr 15288) was 

used as the susceptible control. All the assessments were done 

with one replicate and were repeated once. 

Adult Evaluation 

All the emmer entries were evaluated for resistance in fi eld tests in 

stem rust nurseries planted in St. Paul, MN, (April to July 2010) 

and in Debre Zeit, Ethiopia (June to October 2010). Accessions 

rated as resistant with a maximum 30% stem rust severity and 

moderately susceptible infection response or lower in the 2010 

Debre Zeit fi eld nursery were further evaluated in the Debre Zeit 

and St. Paul nurseries in May 2011 and July 2011, respectively. 

In St. Paul, the nursery was inoculated with a composite of six 

U.S. races (TPMKC, RKQQC, RCRSC, QTHJC, QFCSC, 

and MCCFC). Accessions were planted in single 1-m-row plots. 

In 2010, the Debre Zeit nursery was artifi cially inoculated with 

race TTKSK and a bulk of Ethiopian isolates (with unknown race 

identities) collected from durum lines at the Debre Zeit Research 

Center at a ratio of 50:50 whereas in 2011 the inoculum was composed 

only of a bulk of Ethiopian isolates. Accessions were planted 

in double 1-m-row plots. In both nurseries, continuous rows of 

stem rust spreader (mixture of susceptible cultivars) were planted 

perpendicular to all entries to facilitate inoculum buildup and uniform 

dissemination. Spreader rows were artifi cially inoculated by 

needle injection two to three times at a weekly interval starting at 

stem elongation (stage Zadoks 31) (Zadoks et al., 1974). Urediniospores 

were suspended in distilled water plus one drop of Tween 20 

per 0.5 L of suspension and delivered with a hypodermic syringe 

into the base of the stems. Disease assessment was done at the 

soft-dough stage of plant growth. Due to diff erences in maturity 

among emmer entries, three data points were recorded at 1 and 

2 wk interval starting when the fi rst entries reach the soft-dough 

stage. Plants were evaluated for their infection response (pustule 

type and size) (Roelfs et al., 1992) and stem rust severity following 

the modifi ed Cobb scale (Peterson et al., 1948). Infection 

responses resistant and resistant to moderately resistant were considered 

as indicative of resistance, and infection responses moderately 

resistant, moderately resistant to moderately susceptible, and 

moderately susceptible with a maximum 30% stem rust severity of 

moderately or intermediate resistant. 

Inheritance and Allelism Studies 

To determine the genetic control of resistance to wheat stem 

rust at the seedling stage, crosses between resistant and susceptible 

emmer wheat accessions were evaluated. The F 1 plants 

were evaluated for response to race TTKSK to determine 

gene action. The F 2 populations were evaluated against races 

TTKSK, TRTTF, and TTTTF to determine the inheritance 

of resistance. The F 2:3 families were evaluated only against race 

TTKSK. The F 2:3 families from CItr 7966 × PI 217640 were 

also evaluated against race TRTTF. Twenty plants from each 

F 2:3 family were tested. According to Hanson (1958), this F 2:3 

CROP SCIENCE, VOL. 52, SEPTEMBER–OCTOBER 2012 WWW.CROPS.ORG 2235

Table 1. Isolate designation, origin, and virulence phenotype of Puccinia graminis f. sp. tritici races used to evaluate resistance 

in emmer wheat (Triticum turgidum subsp. dicoccon). 

Race Isolate Origin Avirulence and virulence formula 

TTKSK 04KEN156/04 Kenya Sr24 36 Tmp/Sr5 6 7b 8a 9a 9b 9d 9e 9g 10 11 17 21 30 31 38 McN 

TRTTF 06YEM34-1 Yemen Sr8a 24 31/Sr5 6 7b 9a 9b 9d 9e 9g 10 11 17 21 30 36 38 McN Tmp 

TTTTF 02MN84A-1-2 United States Sr24 31/Sr5 6 7b 8a 9a 9b 9d 9e 9g 10 11 17 21 30 36 38 McN Tmp 

TPMKC 74MN1409 United States Sr6 9a 9b 24 30 31 38/Sr5 7b 8a 9d 9e 9g 10 11 17 21 36 McN Tmp 

RKQQC 99KS76A-1 United States Sr9e 10 11 17 24 30 31 38 Tmp/Sr5 6 7b 8a 9a 9b 9d 9g 21 36 McN 

RCRSC 77ND82A United States Sr6 8a 9e 11 24 30 31 38 Tmp/Sr5 7b 9a 9b 9d 9g 10 17 21 36 McN 

QTHJC 75ND717C United States Sr7b 9a 9e 24 30 31 38 36 Tmp/Sr5 6 8a 9b 9d 9g 10 11 17 McN 

QFCSC 06ND76C United States Sr6 7b 9b 9e 11 24 20 31 36 38 Tmp/Sr 5 8a 9a 9d 9g 10 17 21 McN 

QCCLC 07WA140-17-1 United States Sr6 7b 8a 9b 9d 9e 10 11 24 30 31 38 Tmp/Sr5 9a 9g 17 21 McN 

MCCFC 59KS19 United States Sr6 8a 9a 9b 9d 9e 11 21 24 30 31 36 38/Sr5 7b 9g 10 17 McN Tmp 

family size has a 99% probability of distinguishing between 

segregating and nonsegregating families for monogenic inheritance. 

The allelism tests involved testing F 2 populations derived 

from crosses between two resistant accessions. The χ 2 test was 

applied to determine the goodness-of-fi t to expected genetic 

ratios in the F 2 and F 2:3 generations. Additionally, χ 2 value also 

was calculated from a contingency table to assess the relationship 

of the reactions of F 2:3 families from the CItr 7966 × PI 

217640 cross to races TTKSK and TRTTF. 

RESULTS AND DISCUSSION 

Seedling Evaluation 

A high frequency of resistance to the three races evaluated at 

the seedling stage was observed in this emmer wheat collection, 

as 107 (31.8%), 123 (36.6%), and 148 (44.8%) accessions 

exhibited a resistant reaction to race TTKSK, TRTTF, and 

TTTTF, respectively (Table 2). Ninety (25.1%) accessions 

were resistant to all three races. These results demonstrate 

that emmer wheat is a rich source of stem rust resistance. 

Resistance to wheat stem rust at the seedling stage was 

reported by Beteselassie et al. (2007) in Ethiopian emmer 

wheat, as 18 of 41 accessions were resistant to a bulk of six 

local isolates. The frequency of resistance to race TTKSK 

observed in this emmer collection was similar to the one 

reported in wild emmer [T. turgidum subsp. dicoccoides (Körn. 

ex Asch. & Graebn.) Thell.] (Olivera et al., 2009) and other 

cultivated tetraploids (Olivera et al., 2011). The characteristic 

infection types of the emmer wheat resistant accessions to the 

three races ranged from 2 = to 2 + , and lower infection types 

(ITs) (IT = 0; to 1) were observed in nine (8.2%), 15 (13.6%), 

and 33 (30.0%) accessions to races TTKSK, TRTTF, and 

TTTTF, respectively (data not shown). The predominance 

of infection types ranging from 2 = to 2 + appears to be a common 

feature in cultivated tetraploid wheat as similar results 

were observed in wild emmer, Polish, Oriental, and Pollard 

wheat (P. Olivera and Y. Jin, unpublished data, 2011). 

Ten diff erent infection type patterns were obtained 

when the 107 TTKSK-resistant accessions were 

characterized with six additional U.S. races (Table 3). 

Eighty-two (76.7%) accessions were resistant to all 

evaluated races whereas 13 accessions were susceptible to 

Table 2. Number and percentage of emmer wheat (Triticum 

turgidum subsp. dicoccon) accessions exhibiting resistant, 

susceptible, and heterogeneous † reaction to Puccinia 

graminis f. sp. tritici races TTKSK, TRTTF, and TTTTF. 

TTKSK TRTTF TTTTF 

No. % No. % No. % 

Resistant 107 31.8 123 36.6 148 44.8 

Susceptible 215 64.0 199 59.2 176 53.3 

Heterogeneous 14 4.2 13 4.2 6 1.8 

† Accessions that contained both resistant and susceptible plants. 

only one race. Six patterns were not duplicated. These 

results suggest that resistance to TTKSK in emmer wheat 

is not highly diverse but may be useful against a broad 

spectrum of races. A higher level of diversity for stem rust 

resistance was observed in free threshing tetraploid wheat 

(McVey, 1991). In our study, we observed a lower level 

of diversity of stem rust resistance than that reported by 

McVey (1991), but this result may be explained by the fact 

that we characterized the accessions that were resistant 

to race TTKSK only. When we evaluated the accessions 

susceptible to race TTKSK against four additional U.S. 

races, we identifi ed over 30 infection type patterns (data 

not shown). Emmer wheat has contributed race specifi c 

stem rust resistance genes. In particular, Sr13 and Sr14 

were derived from Khapli emmer (Heermann and Stoa, 

1956). These genes exhibit a moderate level of resistance 

(IT = 2 + ) and susceptibility (IT = 4) to race TTKSK, 

respectively (Jin et al., 2007). In addition, Sr13 exhibits 

a high reaction (IT = 3 + ) to race TRTTF (Olivera et al., 

2012). The infection types to races TTKSK, TRTTF, 

and TTTTF observed in the TTKSK resistant accessions 

indicate that resistance genes present in these accessions 

were likely not Sr13 or Sr14. 

Adult Evaluation 

Minor diff erences in maturity were observed among the 

emmer entries. At both locations, about 80% of the accessions 

reached the soft-dough stage of plant growth on 

the same week (90–97 d after planting). Five percent of 

the entries reached the soft-dough stage 8 to 10 d before 


Table 3. Number and infection type † patterns of emmer wheat (Triticum turgidum subsp. dicoccon) accessions resistant to 

race TTKSK of Puccinia graminis f. sp. tritici at the seedling stage. 

Number of lines TTKSK TRTTF TTTTF TPMKC 

Races 

RKQQC RCRSC QTHJC QCCLC MCCFC 

82 L L L L L L L L L 

6 L H L L L L L L L 

4 L L H L L L L L L 

1 L L L H L L L L L 

1 L L L L L H L L L 

1 L L L L L L L L H 

1 L H H L L L L L L 

1 L H L H L L L L L 

1 L H H H H H L L L 

1 L L L H H H H H H 

† Infection types observed on seedlings at 14 d postinoculation using a 0 to 4 scale according to Stakman et al. (1962), in which L stands for low infection types 0, ;, 1, 2, or 

combinations and H stands for high infection types 3 or 4. 

Table 4. Number and percentage of emmer wheat (Triticum turgidum subsp. dicoccon) accessions † in fi eld evaluations in 

Debre Zeit and St. Paul in 2010 and 2011 according to infection response and disease severity. 

2010 2011 

Disease evaluation Debre Zeit St. Paul Debre Zeit St. Paul 

Infection response ‡ Severity § No. % No. % No. % No. % 

R T–30 13 4.0 51 16.0 0 0.0 25 15.9 

R 31–60 0 0.0 0 0.0 0 0.0 0 0.0 

RMR–MRR T–30 11 3.4 25 7.9 5 3.2 22 14.0 

RMR–MRR 31–60 0 0.0 5 1.6 0 0.0 0 0.0 

MR T–30 27 8.3 21 6.6 19 12.1 18 11.5 

MR 31–60 0 0.0 8 2.5 0 0.0 0 0.0 

MRMS–MSMR T–30 74 22.7 17 5.3 20 12.7 11 7.0 

MRMS–MSMR 31–60 7 2.1 28 8.8 1 0.6 3 1.9 

MS T–30 32 9.8 6 1.9 6 3.8 6 3.8 

MS 31–60 10 3.1 25 7.9 1 0.6 14 8.9 

MS 61–100 0 0.0 3 0.9 0 0.0 0 0.0 

MSS–SMS T–30 40 12.3 1 0.3 11 7.0 6 3.8 

MSS–SMS 31–60 37 11.3 36 11.3 33 21.0 31 19.7 

MSS–SMS 61–100 0 0.0 4 1.3 0 0.0 0 0.0 

S T–30 21 6.4 0 0.0 9 5.7 0 0.0 

S 31–60 54 16.6 37 11.6 40 25.5 18 11.5 

S 61–100 0 0.0 51 16.0 9 5.7 1 0.6 

Total 326 100 318 100 157 100 157 100 

† Accessions characterized as resistant to moderately resistant with a maximum 30% stem rust severity and maximum moderately susceptible infection response at the 2010 

Debre Zeit fi eld nursery were evaluated in 2011 in St. Paul and Debre Zeit. 

‡ Pustule type and size (Roelfs et al., 1992). R, resistant; RMR, resistant to moderately resistant; MRR, moderately resistant to resistant; MR, moderately resistant; MRMS, 

moderately resistant to moderately susceptible; MSMR, moderately susceptible to moderately resistant; MS, moderately susceptible; MSS, moderately susceptible to 

susceptible; SMS, susceptible to moderately susceptible; S, susceptible. 

§ Stem rust severity following the modifi ed Cobb scale (Peterson et al., 1948). T, traces. 

whereas 15 to 17% of the entries reached the soft-dough 

stage 2 wk after the main group. A higher frequency of 

susceptible accessions was observed in the late maturity 

group. Resistance to wheat stem rust at the adult stage was 

observed in emmer, as 164 (50.3%) and 161 (50.6%) accessions 

exhibited resistant to moderately resistant response 

in the 2010 Debre Zeit and St. Paul fi eld nurseries, respectively 

(Table 4). Accessions characterized as resistant with 

a maximum 30% stem rust severity and maximum moderately 

susceptible infection response in the Debre Zeit 

fi eld nursery in 2010 were further evaluated in both nurseries 

in 2011. Fifty-one (32.5%) and 85 (54.1%) accessions 

exhibited resistant to moderately resistant response in the 

2011 Debre Zeit and St. Paul fi eld nurseries, respectively 

(Table 4). The higher disease pressure and the inoculum 

composition in the off -season nursery (May 2011) in 

Debre Zeit may explain why only 32% of the accessions 

resistant in 2010 remained resistant in the 2011 evaluations. 

The lower frequencies of resistance in Debre Zeit 

compared to St. Paul in 2010 and 2011 may indicate the 

presence of races of P. graminis f. sp. tritici in the Debre Zeit 

nursery that overcome resistance genes in emmer wheat 

that are eff ective against U.S. races. 


Table 5. Stem rust reaction of emmer wheat (Triticum turgidum subsp. dicoccon) accessions in fi eld evaluations in Debre Zeit 

and St. Paul in 2010 and 2011, and seedling evaluations to races TTKSK, TRTTF, TTTTF, TPMKC, RKQQC, QTHJC, and MCCFC 

of Puccinia graminis f. sp. tritici. 

Field evaluation † Seedling evaluation ‡ 

Debre Zeit St. Paul TTKSK TRTTF TTTTF TPMKC RKQQC QTHJC MCCFC 

Accession 2010 2011 2010 2011 04KEN156/04 06YEM34-1 01MN84A-1-2 74MN1409 99KSD76A-1 75ND717C 59KS19 

CItr 4013 40MSMR 30MRMS 30RMR 10RMR 33+ 4 3+ 3–3 2-; 2-; ;1- 

CItr 12213 10MRR 20MR 30MR 20MR 2N 22- ;2-N 2+ 2- 2-N 2-N 

CItr 12214 20MRMS 30MR 30MR 30MR 2N 22-; 2-N 22+N 2- 2-N 2–2N 

PI 41024 10R 20MR 40MRR 20MRR 2-N 2- 2-N 2-N 2- 2- 2-;N 

PI 94624 20MR 20 MS 10R 10R 22+ 4 ;N2- 31; ;N2 2- X 

PI 94625 20MR 10 MR 5R 10RMR 33- 4 ;13 31; X- ;C X- 

PI 94626 10MR 15 MRMS 20R 15MRR 22+ 3+ 1; 3+ ;C1- 2+ 2-;C 

PI 94635 10MR 10 MR, 20S 15RMR ;C2- 2=1; 2-; ;C2- ;C2- 2-; ;C 

PI 94656 10R 20MRMS 20RMR 20MRR 2-N 2- ;2- 2-N 2- 2- ;N2- 

PI 94665 20MRMS 30MSMR 20RMR 30MS 33+ 33+ 3+ 2-/3–3 2=; 3- 3–3 

PI 94674 30MRMS 30MS 30MR 5R ;2-N ;1 ;N1- 2-; ;CN 2-; ;CN1- 

PI 94747 5R 10MRR 30RMR 20RMR 2-N 2-; 2-; 2-N 2- 2-N ;N2- 

PI 101971 20R 20RMR 30MR 25MR 2-N 2-; ;2- 2-N 2- 2-;N 2-N 

PI 133134 5R 20MR 40MRR 20MR 22- 2-; ;2- 2-N 2-; 2-;N 2-;N 

PI 193879 20MR 20 MR, 40SMS 50MR 40MRMS 2-N 2 ;N 2-N 2-;N 2-; ;1 

PI 193880 30MSMR 20MR, 50SMS 40MRMS 30MRMS ;12- 2–2= ;2- ;12- ;12- ;2–1 ;1 

PI 193881 30MSMR 30MSS 40MR 30MR 3+ 3+3 33+ 3–3 3 3–2+ 3- 

PI 193882 40MRMS 30MR, 30S 50MRMS 30MS ;2- 2- ;2- 2- 22- 2-; ;1 

PI 193883 20MR 30MR, 40S 30MR 30MS ;2- 2–2 2- 2–2 2-; ;2- ;2- 

PI 197481 20MSMR 20MSMR 30MRR 20MR ; ;1- ;- ;C ;C ;2–1 ;CN 

PI 217637 10R 20MRMS 30RMR 20RMR 2 22- 2- 2-N 2- 2-; 2-;N 

PI 217639 5R 20RMR 30R 30RMR 2-N 2 2-;N 2-; 2-;N ;2- 2-N; 

PI 217640 10R 20RMR 20R 30R 2-N 2-; 2-;N 2-;N 2-; 2-; ;N2- 

PI 225332 10MR 20MSMR 10R 5R 3–2; 32; ;32 32; ;23 ;32 ;23- 

PI 248991 20RMR 25MRMS 50MR 30MR 2-N 2- 3- ;N2- 2- 2- 2-;N 

PI 254163 20MRMS 30MS 10R 10R 2-;N 4 3 3-; 2;N 3-;N 3-; 

PI 254165 10MSMR 30MSMR 5R 32; 3+2; 3–2; 3–2; 3–2; 3–2; 32; 

PI 254167 30MSMR 30MSMR 10R 10R 3 3+ ;N 2+3 3-; 32; 13; 

PI 254175 10MRMS 30MSMR 5R 5R 3–2; 4 32; 32; 23-; 32; ;3- 

PI 275996 20MRR 30MR 30R 20MR 2+3- 2- ;3- 2+3- 2- ;3- 2–2 

PI 298582 40MSMR 40MS 50MRMS 30MS 22+ 22+ 2 22+ 22+ 22+ 2-; 

PI 310471 20RMR 40MRMS 40MR 30MRR 2 22- 2- 2 2- 2- 2N 

PI 319869 30MS 30MSS 50MR 30MR 22- 2 2- 2–2 2- 2- 2-; 

PI 322232 20MR 30MRMS 40MR 30MR 22+ 22+ 2-; 2N 2- 2-N 2-; 

PI 324076 20RMR 30MR 40MRMS 20MR 2+ 22+ ;2- 2–2N 2-; 2-N 2-N 

PI 352548 20MR 20MR 20MR 20MSMR 22- 2 2 2-N 2- 2–2N 2-N 

PI 355477 20RMR 30MRMS 30MR 20R 2 2 ;C 2+2 2 2N 2-N 

PI 470739 20MRMS 10MR, 5MS 5R 5R 32 32 32; 2–2 2- 2- X- 

PI 532304 10MRMS 20MRMS 40RMR 20MR 3+ 3+ 3+3 3- 3 2+ 33- 

† Plants evaluated for infection response (Roelfs et al., 1992) and severity (0–100) following the modifi ed Cobb scale (Peterson et al., 1948). R, resistant; RMR, resistant 

to moderately resistant; MRR, moderately resistant to resistant; MR, moderately resistant; MRMS, moderately resistant to moderately susceptible; MSMR, moderately 

susceptible to moderately resistant; MS, moderately susceptible; MSS, moderately susceptible to susceptible; SMS, susceptible to moderately susceptible; S, susceptible. 

‡ Infection types observed on seedlings at 14 d postinoculation using a 0 to 4 scale according to Stakman et al. (1962), where infection types (ITs) of ;, 1, 2, or X are considered 

as a low IT and ITs of 3 or higher are considered as a high IT. N denotes excessive necrosis. “/” indicated accessions were heterogeneous with dominant type given fi rst. 

Forty-one (26.1%) accessions were resistant to 

moderately resistant in the two nurseries in 2011, and 39 

accessions exhibited a resistant to moderately resistant 

response in the Debre Zeit and St. Paul nurseries in 2010 

and 2011. Twenty-eight of these resistant accessions in 

fi eld evaluations exhibited a resistant reaction to races 

TTKSK, TRTTF, TTTTF, TPMKC, RKQQC, QTHJC, 

and MCCFC in seedling evaluations (Table 5). Selection 

of resistance based on seedling tests can be eff ective, as 

resistance detected at the seedling stage remains eff ective 

at the adult stage. Four accessions (CItr 4013, PI 94665, 

PI 193881, and PI 532304) that were susceptible to races 

TTKSK, TRTTF, and TTTTF in seedling evaluations 

remained resistant to moderately resistant across the two 


Table 6. Disease reaction of F 1 plants and segregation of F 2 populations of various crosses of emmer wheat (Triticum turgidum 

subsp. dicoccon) to race TTKSK of Puccinia graminis f. sp. tritici. 

Cross † 

F plants 1 F plants 

2 

No. plants tested Infection type Resistant (R) Susceptible (S) Ratio tested (R:S) χ2 p-value 

CItr 7966 (S) × PI 101971 (R) 2 2 + 3− 81 24 3:1 0.257 0.612 

CItr 7966 (S) × PI 193883 (R) 2 3/3 + 31 73 1:3 1.282 0.258 

CItr 7966 (S) × PI 217640 (R) 2 2 + 92 29 3:1 0.069 0.793 

CItr 7966 (S) × PI 298582 (R) 2 4 20 92 1:3 3.048 0.081 

CItr 7966 (S) × PI 319869 (R) 2 3/33 + 25 98 1:3 1.434 0.231 

PI 101971 (R) × PI 217640 (R) 2 2−N 112 0 – – – 

PI 193883 (R) × PI 298582 (R) 2 2 105 0 – – – 

PI 193883 (R) × PI 319869 (R) 2 2− 145 0 – – – 

PI 319869 (R) × PI 298592 (R) 2 2 + 132 0 – – – 

PI 217640 (R) × PI 193883 (R) 2 2 + 101 6 13:3 0.075 0.784 

PI 298582 (R) × PI 101971 (R) 2 22 + 146 6 13:3 1.772 0.183 

† Female parent × male parent; (R) and (S) indicate the resistant and susceptible parent, respectively. 

evaluations performed at the adult stage (Table 5). These 

results may indicate the presence of genes for adult plant 

resistance (APR) in these accessions. Sr2, an important gene 

for stem rust resistance (McIntosh, 1988) was transferred to 

hexaploid wheat from Yaroslav emmer (McFadden, 1930). 

Sr2 is reported in association with pseudo-black chaff , a 

black pigmentation that develops in the glumes and around 

stem internodes (Hare and McIntosh, 1979). Pseudo-black 

chaff and black internode were observed in a number of 

emmer accessions (PI 94624, PI 94625, PI 94626, PI 94674, 

PI 225332, PI 248991, PI 254163, PI 254165, PI 254167, 

PI 254175, PI 352548, and PI 532304). These accessions 

are being investigated further for the presence of Sr2 based 

on stem rust evaluations in seedling and adult plant stages 

as well as available markers (Mago et al., 2011). Accessions 

CItr 4013, PI 94665, and PI 193881 did not exhibit the 

Sr2 phenotype. Additional data are needed to confi rm the 

presence of APR genes in these accessions and determine 

the genetic relationship between these genes and Sr2. 

Inheritance and Allelism Studies 

The infection types displayed by the F 1 plants (IT = 2 + to 2 + 3 − ) 

from the crosses between the resistant accessions PI 101971 

and PI 217640 and the segregation ratios observed in the 

resulting F 2 progeny (fi t to a 3:1 ratio for resistant:susceptible) 

indicate that in both accessions, seedling resistance to race 

TTKSK was controlled by a single gene with partial dominance 

eff ect (Table 6). On the other hand, F 1 plants from the 

crosses between resistant accessions PI 193883, PI 298582, 

and PI 319869 and susceptible accessions exhibited ITs (3/33 + 

to 4) that were similar to the susceptible parent (Table 6). 

The number of resistant:susceptible plants in F 2 fi t a 1:3 ratio 

(Table 6), indicating that resistance to race TTKSK in accessions 

PI 193883, PI 298582, and PI 319869 was controlled 

by a single recessive gene. In the F 2:3 generation, the populations 

segregated in a 1:2:1 ratio for homozygous resistant:se 

gregating:homozygous susceptible families, confi rming that 

a single gene conferred resistance to race TTKSK (Table 7). 

The simple inheritance of TTKSK resistance in the fi ve resistant 

emmer parents should simplify the transfer of resistance 

to durum and bread wheat. Accessions carrying the partially 

dominant gene (PI 101971 and PI 217640) exhibited a higher 

level of resistance at the adult stage comparing to the accessions 

that carry the recessive gene (PI 193883, PI 298582, 

and PI 319869) (Table 5). Five emmer accessions (CItr 12213, 

PI 41024, PI 94747, PI 133134, and PI 217639) exhibited a 

similar infection type pattern at the seedling stage and a level 

of resistance in fi eld evaluations that is comparable to the one 

observed in accessions PI 101971 and PI 217640 (Table 5). 

These accessions may carry the same resistance gene eff ective 

against TTKSK. All these accessions are good candidates for 

use in wheat breeding programs. 

In the allelism test, the F 2 population derived from 

the cross between the two resistant accessions carrying 

partially dominant genes (PI 101971 and PI 217640) 

produced only resistant progeny to race TTKSK (Table 

6). This indicated that the accessions carried resistance 

alleles that were allelic or diff erent genes that are linked 

to each other. A similar result was observed in the F 2 

populations derived from crosses between the three 

resistant accessions carrying recessive genes (PI 193883, PI 

298582, and PI 319869). On the other hand, segregation 

in F 2 populations derived from crosses between the 

resistant accessions carrying dominant and recessive genes 

(PI 217640 × PI 193883, and PI 298582 × PI 101971) fi t 

a 13:3 ratio for resistant and susceptible plants (Table 6). 

This indicated that the dominant and recessive resistance 

genes segregated independently. Beteselassie et al. (2007) 

also reported the presence of diverse stem rust resistance 

genes in a group of 18 Ethiopian emmer wheat accessions. 

Genetic diversity for stem rust resistance has also been 

observed in wild emmer, in which six stem rust resistant 

accessions were postulated to each carry a diff erent gene 

(Bai and Knott, 1994). 

To identify additional stem rust resistance genes in 

the selected resistant parents, we evaluated the F 2 progeny 


Table 7. Segregation of F 2:3 families of various crosses of emmer wheat (Triticum turgidum subsp. dicoccon) to race TTKSK of 

Puccinia graminis f. sp. tritici. 

Cross † Race 

for their reaction to races TRTTF and TTTTF. No 

additional resistance gene was identifi ed when crosses 

were evaluated against race TRTTF (Table 8). The χ 2 

value obtained from the contingency table indicated a 

signifi cant association in the reaction to races TTKSK and 

TRTTF in the F 2:3 families from the cross CItr 7966 × PI 

217640 (p = 1.40 −39 ). In accession PI 319869, resistance to 

TRTTF was conferred by a single dominant gene (Table 

8). This gene may be diff erent from the one eff ective 

against race TTKSK (recessive gene) or may indicate a 

change in the dominance relationship in the resistance 

gene. Kolmer and Dyck (1994) reported a change in the 

expression of resistance in Thatcher lines from completely 

dominant to recessive when Puccinia triticina isolates 

were homozygous or heterozygous for avirulence. Two 

resistance genes eff ective against race TTTTF were 

identifi ed in each of the fi ve resistant parents. Progenies 

segregated in a 15:1 or 13:3 ratio for resistant:susceptible 

F 2 plants, indicating the presence of two dominant genes 

or one dominant and one recessive gene, to race TTTTF 

(Table 8). The existence of a number of stem rust resistance 

genes appears to be a common feature of tetraploid wheat 

as accessions with multiple stem rust resistance genes have 

been described in emmer wheat Khapli (Sr13 and Sr14) 

(Heermann and Stoa, 1956), wild emmer (Knott et al., 

2005; Olivera et al., 2011), and Persian [Triticum turgidum 

subsp. carthlicum (Nevski) Á. Löve & D. Löve] and Pollard 

(T. turgidum subsp. turgidum) wheat (Olivera et al., 2011). 

The use of races with diff erent virulence spectrum and 

origin proved to be an effi cient tool to identify multiple 

stem rust resistance genes in individual accessions. 

F 2:3 families ‡ 

HR Seg. HS Ratio tested (HR:Seg:HS) p-value 

CItr 7966 (S) × PI 101971 (R) TTKSK 31 48 28 1:2:1 0.522 





‡ HR, homozygous resistant; Seg., segregating; HS, homozygous susceptible. 

Table 8. Disease reaction of F 2 populations of various crosses of emmer wheat (Triticum turgidum subsp. dicoccon) to races 

TRTTF and TTTTF of Puccinia graminis f. sp. tritici. 

Cross † 

Resistant (R) Susceptible (S) 

TRTTF TTTTF 

Ratio tested 

(R:S) p-value Resistant Susceptible 

Ratio tested 

(R:S) p-value 

CItr 7966 (S) × PI 101971 (R) 78 32 3:1 0.322 129 12 15:1 0.267 

CItr 7966 (S) × PI 193883 (R) 28 45 1:3 0.008 117 15 13:3 0.030 

CItr 7966 (S) × PI 217640 (R) 49 17 3:1 0.145 209 34 13:3 0.057 

CItr 7966 (S) × PI 298582 (R) 11 40 1:3 0.571 104 23 13:3 0.853 

CItr 7966 (S) × PI 319869 (R) 38 11 3:1 0.507 125 15 13:3 0.015 


CONCLUSIONS 

The results of this study demonstrate that emmer wheat 

could serve as a source of resistance to race TTKSK. A 

number of accessions exhibited a resistant response in fi eld 

evaluations and resistant reaction to race TTKSK and all the 

races evaluated at the seedling stage (Table 5). These accessions 

can provide with resistance genes that are eff ective 

against TTKSK and other races with broad virulence. Two 

genes eff ective against race TTKSK have been identifi ed in 

this study. In particular, the partially dominant gene present 

in accessions PI 101971 and PI 217640 confers a high level of 

resistance in fi eld evaluations. This gene is a good candidate 

for use in wheat breeding programs. Further genetic studies 

are required to confi rm the presence of additional eff ective 

genes in the resistant accessions. Eff orts should be made to 

incorporate these eff ective genes from emmer wheat into 

adapted backgrounds. Since emmer wheat shares the same 

genome as durum wheat and is in cultivated form, resistance 

genes should be easily transferred to durum wheat by 

conventional breeding approaches. 

Acknowledgments 

This research is funded by USDA-ARS and the Durable Rust 

Resistance of Wheat (DRRW), Cornell University. The authors 

acknowledge Lucy Wanschura, Sam Gale, and GebreHiwot 

Abraha for their technical assistance. 

References 

Bai, D., and D.R. Knott. 1994. Genetic studies of leaf and stem rust 

resistance in six accessions of Triticum turgidum var. dicoccoides. 

Genome 37:405–409. doi:10.1139/g94-057 

Beteselassie, N., C. Fininsa, and A. Badebo. 2007. Sources 

of resistance to stem rust (Puccinia graminis f. sp. tritici) in 


Ethiopian tetraploid wheat accessions. Genet. Resour. Crop 

Evol. 54:337–343. doi:10.1007/s10722-005-5561-6 

Damania, A.B., S. Hakim, and M.Y. Moualla. 1992. Evaluation of 

variation in Triticum dicoccum for wheat improvement in stress 

environments. Hereditas 116:163–166. 

Gras, M.A. 1980. Disease resistance in wheat: I. T. dicoccum as 

a source of genetic factors against rust and mildew. Genet. 

Agrar. 34:123–132. 

Hammer, K., and P. Perrino. 1984. Further information on farro 

(Triticum monococcum L. and Triticum dicoccum Schrank) in South 

Italy. Kulturpfl anze 32:143–151. doi:10.1007/BF02002075 

Hanson, W.D. 1958. Minimum family sizes for the planning of 

genetic experiments. Agron. J. 51:711–715. doi:10.2134/agron 

j1959.00021962005100120005x 

Hare, R.A., and R.A. McIntosh. 1979. Genetic and cytogenetic 

studies of durable adult-plant resistances in ‘Hope’ and related 

cultivars to wheat rusts. Z. Pfl anzenzuchtg. 83:350–367. 

Heermann, R.M., and T.E. Stoa. 1956. New durum wheats resistant 

to 15B. N. Dakota Agric. Exp. Stn. Farm Res. 18:75–81. 

Jin, Y., and R.P. Singh. 2006. Resistance in U.S. wheat to recent 

eastern African isolates of Puccinia graminis f. sp. tritici with 

virulence to resistance gene Sr31. Plant Dis. 90:476–480. 

doi:10.1094/PD-90-0476 

Jin, Y., R.P. Singh, R.W. Ward, R. Wanyera, M. Kinyua, P. 

Njau, T. Fetch, Z.A. Pretorius, and A. Yahyaoui. 2007. 

Characterization of seedling infection types and adult plant 

infection responses of monogenic Sr gene lines to race TTKS 

of Puccinia graminis f. sp. tritici. Plant Dis. 91:1096–1099. 

doi:10.1094/PDIS-91-9-1096 

Jin, Y., L.J. Szabo, Z.A. Pretorius, R.P. Singh, R. Ward, and T. 

Fetch, Jr. 2008. Detection of virulence to resistance gene Sr24 

within race TTKS of Puccinia graminis f. sp. tritici. Plant Dis. 

92:923–926. doi:10.1094/PDIS-92-6-0923 

Knott, D.R., D. Bai, and J. Zale. 2005. The transfer of leaf and stem 

rust resistance from wild emmer wheats to durum and common 

wheat. Can. J. Plant Sci. 85:49–57. doi:10.4141/P03-212 

Kolmer, J.A., and P.L. Dyck. 1994. Gene expression in the Triticum 

aestivum-Puccinia recondita f. sp. tritici gene-for-gene system. 

Phytopathology 84:437–440. doi:10.1094/Phyto-84-437 

Kuckuck, H. 1970. Primitive wheats. In: OH Frankel and 

E. Bennett, editors, Genetic resources in plants – Their 

exploration and conservation. F. A. Davis Company. 

Philadelphia, PA. p. 249–266. 

Liu, X.M., G.L. Brown-Guedira, J.H. Hatchett, J.O. Owuoche, 

and M.S. Chen. 2005. Genetic characterization and molecular 

mapping of a Hessian fl y-resistance gene transferred from T. 

turgidum ssp. dicoccum to common wheat. Theor. Appl. Genet. 

111:1308–1315. doi:10.1007/s00122-005-0059-3 

Mago, R., G. Brown-Guedira, S. Dreisigacker, J. Breen, Y. Jin, R. 

Singh, R. Appels, E.S. Lagudah, J. Ellis, and W. Spielmeyer. 

2011. An accurate DNA marker assay for stem rust resistance 

gene Sr2 in wheat. Theor. Appl. Genet. 122:735–744. 

doi:10.1007/s00122-010-1482-7 

McFadden, E.S. 1930. A successful transfer of emmer characters to 

vulgare wheat. J. Am. Soc. Agron. 22:1020–1034. doi:10.2134/ 

agronj1930.00021962002200120005x 

McIntosh, R.A. 1988. The role of specifi c genes in breeding for durable 

stem rust resistance in wheat and triticale. In: N.W. Simmonds 

and S. Rajaram, editors, Breeding strategies for resistance to the 

rusts of wheat. CIMMYT, Mexico D.F., Mexico. p. 1–9. 

McVey, D.V. 1991. Reaction of a group of related wheat species (AABB 

genome and AABBDD) to stem rust. Crop Sci. 31:1145–1149. 

doi:10.2135/cropsci1991.0011183X003100050012x 

Nazari, K., M. Mafi , A. Yahyaoui, and R.P. Park. 2009. Detection of 

wheat stem rust (Puccinia graminis f. sp. tritici) race TTKSK (Ug99) 

in Iran. Plant Dis. 93:317. doi:10.1094/PDIS-93-3-0317B 

Oliver, R.E., X. Cai, R.W. Stack, T. Friesen, S. Halley, and S.S. 

Xu. 2008. Fusarium head blight resistance in tetraploid wheat 

(Triticum turgidum L.). Crop Sci. 48:213–222. doi:10.2135/ 

cropsci2007.03.0129 

Olivera, P.D., Y. Jin, A. Badebo, S. Xu, and D. Klindworth. 2011. 

Resistance to race TTKSK of Puccinia graminis f. sp. tritici in 

tetraploid wheat. Phytopathology 101:S132. 

Olivera, P.D., Y. Jin, M. Rouse, A. Badebo, T. Fetch, R.P. Singh, 

and A. Yahyaoui. 2012. Races of Puccinia graminis f. sp. tritici 

with combined virulence to Sr13 and Sr9e in a fi eld stem rust 

screening nursery in Ethiopia. Plant Dis. 96:623–628. 

Olivera, P.D., M. Rouse, and Y. Jin. 2009. Resistance to wheat stem rust 

in spelt wheat, wild emmer and triticale. Phytopathology 99:S97. 

Peterson, R.F., A.B. Campbell, and A.E. Hannah. 1948. A 

diagrammatic scale for estimating rust intensity of leaves and 

stem of cereals. Can. J. Res. Sect. C 26:496–500. doi:10.1139/ 

cjr48c-033 

Pfl üger, L.A., L.M. Martín, and J.B. Alvarez. 2001. Variation in the 

HMW and LMW lutenin subunits from Spanish accessions of 

emmer wheat (Triticum turgidum ssp. dicoccum Schrank). Theor. 

Appl. Genet. 102:767–772. doi:10.1007/s001220051708 

Pretorious, Z.A., Y. Jin, C.M. Bender, L. Herselman, and R. 

Prins. 2011. Seedling resistance to stem rust race Ug99 and 

marker analysis for Sr2, Sr24 and Sr31 in South African wheat 

cultivars and lines. Euphytica doi:10.1007/s10681-011-0476-0 

Pretorius, Z.A., R.P. Singh, W.W. Wagoire, and T.S. Payne. 2000. 

Detection of virulence to wheat stem rust resistance genes Sr31 

in Puccinia graminis f. sp. tritici in Uganda. Plant Dis. 84:2003. 

Roelfs, A.P., D.L. Long, and J.J. Roberts. 1993. Races of Puccinia 

graminis in the United States during 1992. Plant Dis. 77:1122– 

1125. doi:10.1094/PD-77-1122 

Roelfs, A.P., and J.W. Martens. 1988. An international system of 

nomenclature for Puccinia graminis f. sp. tritici. Phytopathology 

78:526–533. doi:10.1094/Phyto-78-526 

Roelfs, A.P., R.P. Singh, and E.E. Saari. 1992. Rust diseases 

of wheat, concepts and methods of disease management. 

CIMMYT, Mexico D.F., Mexico. 

Sayed, H.I. 1985. Diversity of salt tolerance in germplasm collection 

of wheat (Triticum ssp.). Theor. Appl. Genet. 69:651–657. 

doi:10.1007/BF00251118 

Singh, R.P., D.P. Hodson, J. Huerta-Espino, Y. Jin, S. Bhavani, 

P. Njau, S.A. Herrera-Foessel, P. Singh, S. Singh, and V. 

Govindan. 2011. The emergence of Ug99 races of the stem 

rust fungus is a threat to world wheat production. Annu. 

Rev. Phytopathol. 49:465–481. doi:10.1146/annurevphyto-072910-095423 

Singh, R.P., D.P. Hodson, Y. Jin, J. Huerta-Espino, M.G. Kinyua, 

R. Wanyera, P. Njau, and R.W. Ward. 2006. Current status, 

likely migration and strategies to mitigate the threat to wheat 

production from race Ug99 (TTKS) of stem rust pathogen. 

CAB Rev. Perspect. Agric. Vet. Sci. Nutr. Nat. Res. 54:1–13. 

Stakman, E.C., D.M. Steward, and W.Q. Loegering. 1962. 

Identifi cation and physiologic races of Puccinia graminis var. tritici. 

USDA-ARS E-617. U.S. Gov. Print. Off ., Washington, DC. 

Stallknecht, G.F., K.M. Gilbertson, and J.E. Ranney. 1996. 

Alternative wheat cereals as food grains: Einkorn, emmer, 

spelt, kamut, and triticale. In: J. Janick, editor, Progress in 

new crops. ASHS Press, Alexandria, VA. p. 156–170. 


Visser, B., L. Herselman, R.F. Park, H. Karaoglu, C.M. Bender, 

and Z.A. Pretorius. 2010. Characterization of two new 

Puccinia graminis f. sp. tritici races within the Ug99 lineage in 

South Africa. Euphytica 179:119–127. doi:10.1007/s10681- 

010-0269-x 

Wanyera, R., M.G. Kinyua, Y. Jin, and R.P. Singh. 2006. The 

spread of stem rust caused by Puccinia graminis f. sp. tritici, 

with virulence on Sr31 in wheat in Eastern Africa. Plant Dis. 

90:113. doi:10.1094/PD-90-0113A 

Wolday, A., T. Fetch, Jr., D. Hodson, W. Cao, and S. Briere. 2011. 

First report of Puccinia graminis f. sp. tritici races with virulence 

to wheat stem rust resistance genes Sr31 and Sr24 in Eritrea. 

Plant Dis. 95:1591. doi:10.1094/PDIS-07-11-0582 

Yanchenko, I. 1985. A study of interspecifi c hybrids of Triticum 

durum Desf. × Triticum dicoccum (Schrank) Schuebl. and ways 

of using them in durum wheat breeding. Naucho Tek. Eyul. 

Sibirskogo Old. Vashknil. 45:3–7. 

Zadoks, J.C., T.T. Chang, and C.F. Konzak. 1974. A decimal 

code for the growth stage of cereals. Weed Res. 14:415–421. 

doi:10.1111/j.1365-3180.1974.tb01084.x

Resistance to Race TTKSK of Puccinia graminis f. sp. tritici in Emmer ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?