First Report of a Puccinia graminis f. sp. tritici Race Virulent to the Sr24 and Sr31 Wheat Stem Rust Resistance Genes in South Africa

Isolates of Puccinia graminis f. sp. tritici belonging to the Ug99 race group are virulent to a broad spectrum of resistance genes, rendering most of the world's wheat germplasm susceptible to stem rust (3). Following the initial detection of Ug99 (TTKSK, North American [NA] race notation) in Uganda, virulence to the widely used Sr31 resistance gene has been reported from Kenya, Ethiopia, Sudan, and Iran (2,3). In November 2009, a wheat genotype suspected to carry Sr31 showed a susceptible response to stem rust in a disease nursery (29°08′05.02′′S, 30°38′29.18′′E), inoculated with race TTKSP, near Greytown in KwaZulu-Natal, South Africa. Inoculation of urediniospores of the field collection (isolate UVPgt60) onto seedlings of line Federation4*/Kavkaz confirmed virulence for Sr31. In three independent, replicated, and comparative seedling tests, eight single-pustule isolates of UVPgt60 all typed to race PTKST following the NA race nomenclature. These isolates produced compatible infection types (ITs) (3+ to 4) on the Sr31 testers Gamtoos, Sr31/6*LMPG, Federation4*/Kavkaz, Kavkaz, and Clement, whereas isolate UVPgt59 (TTKSP) was avirulent (ITs ;1 to 1) on these genotypes. In addition to Sr31 virulence, the new race differed from TTKSP by producing a lower IT (2 to 2++) on Cns_T.mono_ deriv., the accepted entry for Sr21 in the NA differential set. The UVPgt60 isolates were clearly avirulent on Einkorn (Sr21) (IT ;1=), a response that also differed from those produced by BPGSC, TTKSF, and TTKSP (IT 2). With the exception of Sr21, UVPgt60 isolates had a virulence pattern similar to race TTKST (1), notably the virulence combination for Sr24 and Sr31. Isolate UVPgt60.6 was randomly selected for testing on additional Sr genes and South African wheat cultivars and breeding lines. Similar to the race identification experiments seedling tests were duplicated and compared with reactions produced by TTKSP and other races. Greenhouse temperatures for all seedling tests ranged between 18 and 25°C. On the basis of primary leaf responses, PTKST is avirulent (ITs 0; to 2++) for Sr13, 14, 21, 22, 25, 26, 27, 29, 32, 33, 35, 36, 37, 39, 42, 43, 44, Em, Tmp, and Satu and virulent (ITs 3 to 4) for Sr5, 6, 7b, 8a, 8b, 9a, 9b, 9d, 9e, 9g, 10, 11, 16, 17, 24, 30, 31, 34, 38, 41, and McN. From 103 South African wheat cultivars and lines tested as seedlings, 59 and 47 were susceptible (IT ≥ 3) to races PTKST and TTKSP, respectively. Simple-sequence repeat analysis (4) with selected primer pairs showed that PTKST clusters with isolates belonging to the Ug99 lineage. Subsequent to the collection made at Greytown, stem rust sampled in December 2009 from naturally infected breeders' lines at Cedara (29°32′19.59′′S, 30°16′03.50′′E), KwaZulu-Natal, revealed five isolates with a virulence profile similar to PTKST. On the basis of current evidence it appears that PTKST may be an introduction to South Africa rather than a single-step mutation from local stem rust races. References: (1) Y. Jin et al. Plant Dis. 92:923, 2008. (2) K. Nazari et al. Plant Dis. 93:317, 2009. (3) R. P. Singh et al. Adv. Agron. 98:271, 2008. (4) B. Visser et al. Mol. Plant Pathol. 10:213, 2009.

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First Report of a New TTKSF Race of Wheat Stem Rust (Puccinia graminis f. sp. tritici) in South Africa and Zimbabwe

Plant Disease ◽

10.1094/pdis-12-11-1027-pdn ◽

2012 ◽

Vol 96 (4) ◽

pp. 590-590 ◽

Cited By ~ 45

Author(s):

Z. A. Pretorius ◽

L. J. Szabo ◽

W. H. P. Boshoff ◽

L. Herselman ◽

B. Visser

Keyword(s):

South Africa ◽

South African ◽

Stem Rust ◽

Infection Type ◽

Puccinia Graminis ◽

Nucleotide Polymorphisms ◽

Wheat Stem Rust ◽

Letter Code ◽

Formed Part ◽

Sr Gene

Seven races have been described in the Ug99 race group of Puccinia graminis f. sp. tritici (2). Ug99-related races previously recorded in South Africa are TTKSF, TTKSP, and PTKST (4). In December 2010, severe stem rust infection of the winter wheat cv. Matlabas was observed for the first time in South Africa. Race analysis using the 20 North American (NA) stem rust differential lines and letter code system classified the race as TTKSF. In comparative infection studies in a greenhouse, cv. Matlabas seedlings were susceptible (infection type [IT] 4) to isolate UVPgt61/1 (TTKSF+) collected from Afrikaskop in the eastern Free State, whereas the cultivar was resistant (IT 1 to 2) to stem rust isolates 2013 (TTKSF), UVPgt55 (TTKSF), UVPgt59 (TTKSP), and UVPgt60 (PTKST). Isolate 2013 represents the original collection of race TTKSF in South Africa (1). In addition to the NA differentials, no variation in the IT range of seedlings of lines with Sr7a, 8b, 12, 13, 14, 16, 18, 19, 22, 25, 26, 27, 28, 29, 32, 33, 34, 35, 39, 41, 42, 43, 44, Em, R, Tt2, and Satu was observed between UVPgt61/1 and UVPgt55. With the exception of cv. Matlabas, ITs of 106 South African cultivars likewise did not differentiate UVPgt61/1 and UVPgt55. Seedling IT studies were conducted at least twice. Microsatellite analysis (4) showed that all single pustule isolates established from the original Matlabas isolate formed part of the Ug99 group. When characterized with selected single nucleotide polymorphisms (SNPs), all single pustule isolates shared an identical genotype that differed from UVPgt55 (TTKSF), a foreign introduction into South Africa (1,3). SNP genotype analysis suggests that UVPgt61/1 is genetically dissimilar to UVPgt55, as is Zim1009, another TTKSF+ isolate that was collected from Birchenough in Zimbabwe. Studies are underway to determine the identity of the defeated Sr gene in Matlabas and the cultivar has been added to the South African stem rust differential set. TTKSF+ is the eighth race detected in the Ug99 group. Since no other cultivars or advanced lines were found to carry the Matlabas gene, it is unlikely that race TTKSF+ will threaten wheat production in South Africa. However, the occurrence of a new Ug99-related race emphasizes the variability within this internationally important group. References: (1) W. H. P. Boshoff et al. Plant Dis. 86:922, 2002. (2) R. F. Park et al. Euphytica 179:109, 2011. (3) B. Visser et al. Mol. Plant Pathol. 10:213, 2009. (4) B. Visser et al. Euphytica 179:119, 2011.

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Detection of Variants of Wheat Stem Rust Race Ug99 (Puccinia graminis f. sp. tritici) in Zimbabwe and Mozambique

Plant Disease ◽

10.1094/pdis-04-11-0300 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1188-1188 ◽

Cited By ~ 10

Author(s):

F. Mukoyi ◽

T. Soko ◽

E. Mulima ◽

B. Mutari ◽

D. Hodson ◽

...

Keyword(s):

South Africa ◽

Stem Rust ◽

Genetic Similarity ◽

Puccinia Graminis ◽

Wheat Stem Rust ◽

The North ◽

Ssr Analysis ◽

Kwazulu Natal ◽

Fungal Dna ◽

Race Analysis

The migration of Ug99 variants of Puccinia graminis f. sp. tritici is of concern to global wheat production (1). Seven races have been characterized in the Ug99 lineage (3), three of which occur in South Africa (4). During surveys of wheat fields for Ug99 in Zimbabwe and Mozambique in August and September 2010, high stem rust severities were found at Chiredzi, Chisumbanje, and Birchenough in Zimbabwe and at Rotanda in Mozambique. Stem rust was widespread in the lowlands (<800 m above sea level) of Zimbabwe and trace amounts were present in the mid-altitude areas. In Mozambique, stem rust was only observed at Rotanda (sample Moz1001). Collections from Chiredzi (samples Zim1004 and Zim1005), Chisumbanje (Zim1006), and Birchenough (Zim1009 and Zim1010) yielded viable urediniospores for infection studies. According to race analysis conducted on seedlings of the North American stem rust differential set (2) in a greenhouse at 18 to 25°C, Zim1005 and Zim1006 were typed as PTKST and Zim1004 and Zim1009 as TTKSF. Both TTKSF and PTKST were detected in the Zim1010 sample. Race analysis experiments were conducted three times. Urediniospores of isolate Moz1001 were not viable in infection studies, but yielded fungal DNA for simple sequence repeat (SSR) analysis. Using eight selected SSR primer combinations (4), all six isolates clustered within the Ug99 lineage. Isolates Zim1005, Zim1006, Zim1009, Zim1010, and Moz1001 and the stem rust control races TTKSF, TTKSK, and PTKST grouped into two main clusters, with Zim1009 and Zim1010 clustering together and sharing 88% similarity with the rest of the isolates. Zim1005 and Zim1006 were identical to TTKSF and TTKSK, respectively. Zim1004 shared 96% genetic similarity with the TTKSP control, with these two sharing 74% genetic similarity with the remaining isolates. The SSR data correlated with the infection data, except for Zim1004, which was typed as TTKSF but clustered close to TTKSP. Wheat cvs. SC Nduna, SC Shine, SC Stallion, SC Smart, Kana, Insiza, and Dande are predominant in Zimbabwe. Cv. SC Stallion and other unidentified cultivars were susceptible to P. graminis f. sp. tritici in the field in Zimbabwe. In Mozambique, the tall, local cv. Sitsonko was susceptible to P. graminis f. sp. tritici but no infections were observed on SC Nduna or SC Shine. The similarity in P. graminis f. sp. tritici races in Zimbabwe, South Africa, and Mozambique suggests that inoculum is exchanged within the region and explains the detection of race PTKST in South Africa in 2009. Trajectory models showed winds originating at Birchenough in October 2009, where stem rust was observed, passing directly over KwaZulu-Natal, South Africa within 48 to 72 h. Race PTKST was confirmed from collections in KwaZulu-Natal in November 2009 (4). The confirmation of Sr31 virulence in race PTKST in Zimbabwe is important because it provides new geographical records for an Ug99-related race and puts Southern African cultivars with 1B.1R resistance at risk. References: (1) D. Hodson. Euphytica 179:93, 2011. (2) Y. Jin et al. Plant Dis. 92:923, 2008. (3) R. F. Park et al. Euphytica 179:109, 2011. (4) B. Visser et al. Euphytica 179:119, 2011.

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Detection of Wheat Stem Rust (Puccinia graminis f. sp. tritici) Race TTKSK (Ug99) in Iran

Plant Disease ◽

10.1094/pdis-93-3-0317b ◽

2009 ◽

Vol 93 (3) ◽

pp. 317-317 ◽

Cited By ~ 66

Author(s):

K. Nazari ◽

M. Mafi ◽

A. Yahyaoui ◽

R. P. Singh ◽

R. F. Park

Keyword(s):

Resistance Genes ◽

Stem Rust ◽

Puccinia Graminis ◽

Wheat Cultivars ◽

Alternate Host ◽

Wheat Stem Rust ◽

Wheat Production ◽

Commercial Cultivars ◽

Differential Set ◽

Infection Types

In 2007, new reports of stem rust caused by Puccinia graminis Pers. f. sp. tritici Eriks. in Lorestan and Hamadan provinces of Iran were considered unusual because stem rust had not been recorded previously in the Hamadan area where winter habit wheat cultivars are grown. Detailed investigations in these areas showed significant levels of stem rust in experimental plots and occasionally in farmers' fields, some that showed moderate to high levels of infection. Race analysis of four stem rust samples collected from Borujerd, Hamadan, and Poldokhtar (southwest) and Kelardasht (north) in 2007 was conducted using a modified North American Pgt differential set representing the resistance genes Sr5, 6, 7b, 8a, 9a, 9b, 9d, 9e, 9g, 10, 11, 17, 21, 24, 30, 31, 36, 38, Tmp, and McN, commercial cultivars, and genotypes known to carry the 1B.1R translocation. A race collected from Borujerd in 1997 was also included for comparison. Tests were carried out under standard controlled conditions (1,2). Two isolates from samples collected from Borujerd and Hamadan in 2007 showed high infection types (ITs 33+ to 4) on differential lines carrying resistance genes Sr5, 6, 7b, 8a, 9a, 9b, 9d, 9e, 9g, 10, 11, 17, 21, 30, 31, 38, and McN, and low ITs of ;C1= to 2=, ;C to ;N1=, and 2+ on lines carrying Sr24, Sr36, and SrTmp, respectively. On the basis of the high/low ITs on the 20 differentials in the modified Pgt differential set of North America, the two isolates of Pgt collected from Borujerd and Hamadan in 2007 were identified as race TTKSK. The two isolates from samples collected from Poldokhtar and Kelardasht in 2007 and the isolate collected from Borujerd in 1997 were identified as races TRFSC, TTJQC, and RRHSC, respectively. Race TTKSK identified in the current study produced high ITs of 3+ to 4 on the wheat genotypes Line E*4/Kavkaz, Fed.*4/Kavkaz, Clement, and Mildress and commercial cultivars Falat (Seri 82), Shiroodi (CIMMYT name Attila and Indian name PBW343), Atrak (Kauz), and MV17, all carrying the 1BL.1RS translocation and further confirming virulence for Sr31. The spread of Ug99 to Kenya (1999 to 2002), Ethiopia (2003), and Yemen (2006) suggests progressive migration from Uganda, following the pattern believed to have occurred for the spread of wheat stripe rust pathogen from East Africa in 1986 to India in 1998 (3). Our results are consistent with the TTKSK race identified in Iran migrating from the new African population. Seedling evaluation of Iranian wheat cultivars and advanced lines to isolates of TTKSK from Iran confirmed full susceptibility. These results reinforce the serious threat of race TTKSK to wheat production in Iran. In conclusion, the occurrence of race TTKSK in Iran, the susceptibility of Iranian wheat cultivars to this race, the presence of environmental conditions conducive to disease epidemics in different parts of the country, and the occurrence of the alternate host barberry in many of the mountainous areas of Iran, indicate a new and serious threat to wheat production in Iran and a potentially serious threat to neighboring countries. References: (1) Y. Jin et al. Plant Dis. 91:1096, 2007. (2) Z. A. Pretorius et al. Plant Dis. 84:203, 2000. (3) R. P. Singh et al. CAB Rev. 1 (No. 054), 2006.

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Wheat stem rust in Australia dash 1969-1985

Australian Journal of Agricultural Research ◽

10.1071/ar9920399 ◽

1992 ◽

Vol 43 (3) ◽

pp. 399 ◽

Cited By ~ 29

Author(s):

PK Zwer ◽

RF Park ◽

RA McIntosh

Keyword(s):

Survey Data ◽

Common Wheat ◽

Resistance Genes ◽

Stem Rust ◽

Puccinia Graminis ◽

Wheat Cultivars ◽

Wheat Stem Rust ◽

Cultivar Development ◽

Resistant Genes ◽

Australian Wheat

Pathogenic changes in Puccinia graminis f. sp. tritici (P. g. tritici) in Australia during the period 1969-1985 are reviewed. As found in a previous study covering the period 1954-1968, the frequencies of individual pathotypes were influenced by the combinations of resistance genes present in the most common wheat cultivars. From 1969 to 1978, pathotype composition and diversity varied between the four regions comprising the Australian wheat-growing area. However, from 1978 to 1985, pathotype 343-1,2,3,5,6 predominated in all regions. It is suggested that this pathotype was repeatedly derived from pathotype 326-1,2,3,5,6 at widely separated locations, and that these events facilitated its widespread increase. Another significant event was the specialization of P. g. tritici on triticale. Survey data suggest that pathotype 34-2,12, which rendered cultivar Coorong susceptible, developed from pathotype 34-2, possibly during 1979. A second pathotype which attacked cultivar Satu (designated 34-2,12,13) was detected in 1984. The deployment of different resistant genes in triticale and wheat has resulted in distinct populations within P. g. tritici adapted to each crop. Future Cultivar development for triticale should be aimed at maintaining this divergence.

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Seedling Stage Resistance of Iranian Bread Wheat Germplasm to Race Ug99 of Puccinia graminis f. sp. tritici

Plant Disease ◽

10.1094/pdis-02-12-0138-re ◽

2013 ◽

Vol 97 (3) ◽

pp. 387-392 ◽

Cited By ~ 2

Author(s):

Mohsen Mohammadi ◽

Davoud Torkamaneh ◽

Mehran Patpour

Keyword(s):

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Stem Rust Resistance ◽

Puccinia Graminis ◽

Wheat Cultivars ◽

Breeding Lines ◽

Wheat Germplasm ◽

Stem Rust Resistance Genes ◽

Rust Resistance Genes

Following emergence of Ug99, the new virulent race of Puccinia graminis f. sp. tritici in Africa, a global effort for identification and utilization of new sources of Ug99-resistant germplasm has been undertaken. In this study, we conducted replicated experiments to evaluate the resistance of Iranian wheat germplasm to the TTKSK lineage of the Ug99 race of P. graminis f. sp. tritici. We also evaluated for presence of stem rust resistance genes (i.e., Sr2, Sr24, Sr26, Sr38, Sr39, Sr31, and Sr1RSAmigo) in wheat cultivars and breeding lines widely cultivated in Iran. Our phenotyping data revealed high levels of susceptibility to Ug99 in Iranian bread wheat germplasm. Our genotyping data revealed that Iranian cultivars do not carry Sr24, Sr26, or Sr1RSAmigo. Only a few salt-tolerant cultivars and breeding lines tested positively for Sr2, Sr31, Sr38, or Sr39 markers. In conclusion, the genetic basis for resistance to Ug99 in Iranian wheat cultivars was found to be vulnerable. Acquiring knowledge about existing resistance genes and haplotypes in wheat cultivars and breeding lines will help breeders, cereal pathologists, and policy makers to select and pyramid effective stem rust resistance genes.

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Characterization of Wheat Monogenic Lines with Known Sr Genes and Wheat Lines with Resistance to the Ug99 Race Group for Resistance to Prevalent Races of Puccinia graminis f. sp. tritici in China

Plant Disease ◽

10.1094/pdis-12-19-2736-re ◽

2020 ◽

Vol 104 (7) ◽

pp. 1939-1943

Author(s):

Xian Xin Wu ◽

Qiu Jun Lin ◽

Xin Yu Ni ◽

Qian Sun ◽

Rong Zhen Chen ◽

...

Keyword(s):

Food Security ◽

Stem Rust ◽

Adult Plant ◽

Puccinia Graminis ◽

Wheat Cultivars ◽

Wheat Stem Rust ◽

Wheat Improvement ◽

Wheat Lines ◽

Sr Genes

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most serious fungal diseases in wheat production, seriously threatening the global supply of wheat and endangering food security. The present study was conducted to evaluate wheat monogenic lines with known Sr genes to the most prevalent P. graminis f. sp. tritici races in China. In addition, wheat lines introduced from the International Maize and Wheat improvement Center (CIMMYT) with resistance to the Ug99 race group were also evaluated with the prevalent Chinese P. graminis f. sp. tritici races. The monogenic lines containing Sr9e, Sr21, Sr26, Sr31, Sr33, Sr35, Sr37, Sr38, Sr47, and SrTt3 were effective against races 21C3CTTTM, 34C0MRGSM, and 34C3MTGQM at both seedling and adult-plant stages. In contrast, monogenic lines containing Sr6, Sr7b, Sr8a, Sr9a, Sr9b, Sr9d, Sr9f, Sr9g, Sr13, Sr16, Sr18, Sr19, Sr20, Sr24, Sr28, Sr29, and Sr34 were highly susceptible to these races at both seedling and adult-plant stages. Lines with Sr5, Sr10, Sr13, Sr14, Sr15, Sr17, Sr21, Sr22, Sr23, Sr25, Sr27, Sr29, Sr30, Sr32, Sr36, and Sr39 were resistant to one or more of the tested races. Among the 123 CIMMYT lines, 38 (30.9%) showed varying levels of susceptibility to Chinese P. graminis f. sp. tritici races. The results should be useful for breeding wheat cultivars with resistance to stem rust.

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Identification of stem rust resistance genes in wheat cultivars in China using molecular markers

PeerJ ◽

10.7717/peerj.4882 ◽

2018 ◽

Vol 6 ◽

pp. e4882 ◽

Cited By ~ 7

Author(s):

Xiaofeng Xu ◽

Depeng Yuan ◽

Dandan Li ◽

Yue Gao ◽

Ziyuan Wang ◽

...

Keyword(s):

Molecular Markers ◽

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Genetic Material ◽

Stem Rust Resistance ◽

Wheat Cultivars ◽

Wheat Stem Rust ◽

Stem Rust Resistance Genes ◽

Rust Resistance Genes

Wheat stem rust caused by Puccinia graminis f. sp. tritici Eriks. & E. Henn. (Pgt), is a major disease that has been effectively controlled using resistance genes. The appearance and spread of Pgt races such as Ug99, TKTTF, and TTTTF, which are virulent to most stem rust-resistant genes currently deployed in wheat breeding programs, renewed the interest in breeding cultivars resistant to wheat stem rust. It is therefore important to investigate the levels of resistance or vulnerability of wheat cultivars to Pgt races. Resistance to Pgt races 21C3CTHQM, 34MKGQM, and 34C3RTGQM was evaluated in 136 Chinese wheat cultivars at the seedling stage. A total of 124 cultivars (91.2%) were resistant to the three races. Resistance genes Sr2, Sr24, Sr25, Sr26, Sr31, and Sr38 were analyzed using molecular markers closely linked to them, and 63 of the 136 wheat cultivars carried at least one of these genes: 21, 25, and 28 wheat cultivars likely carried Sr2, Sr31, and Sr38, respectively. Cultivars “Kehan 3” and “Jimai 22” likely carried Sr25. None of the cultivars carried Sr24 or Sr26. These cultivars with known stem rust resistance genes provide valuable genetic material for breeding resistant wheat cultivars.

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RESISTANCE IN WHEAT TO FORMAE SPECIALES TRITICI AND SECALIS OF PUCCINIA GRAMINIS

Canadian Journal of Genetics and Cytology ◽

10.1139/g71-019 ◽

1971 ◽

Vol 13 (1) ◽

pp. 119-127 ◽

Cited By ~ 4

Author(s):

A. K. Sanghi ◽

N. H. Luig

Keyword(s):

Stem Rust ◽

Virulence Genes ◽

Somatic Hybrids ◽

Puccinia Graminis ◽

New Combinations ◽

Wheat Cultivars ◽

Wheat Stem Rust ◽

Formae Speciales ◽

Two Hybrid

Nine genes conditioning resistance to cultures of P. graminis tritici (possessing unusual genes for avirulence), P. graminis secalis, and sexual or somatic hybrids between these formae speciales were found in the wheat cultivars Mentana and Yalta. In Mentana, Sr8 operated against all six cultures utilized; but in Yalta, Sr11 conditioned resistance to only two hybrid cultures. In addition, four other genes in Mentana and three genes in Yalta operated against the cultures.The present study indicates that hybridization between wheat stem rust and rye stem rust can be important in producing new combinations of virulence genes which can attack known genes for resistance in wheat. The implications of such hybridization in relation to the transference to wheat of resistance in rye to P. graminis tritici are discussed.

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Evaluation and identification of stem rust resistance genesSr2,Sr24,Sr25,Sr26,Sr31andSr38in wheat lines from Gansu Province in China

PeerJ ◽

10.7717/peerj.4146 ◽

2017 ◽

Vol 5 ◽

pp. e4146 ◽

Cited By ~ 3

Author(s):

Xiao Feng Xu ◽

Dan Dan Li ◽

Yang Liu ◽

Yue Gao ◽

Zi Yuan Wang ◽

...

Keyword(s):

Resistance Genes ◽

Stem Rust ◽

Rust Resistance ◽

Stem Rust Resistance ◽

Gansu Province ◽

Wheat Cultivars ◽

Wheat Stem Rust ◽

Stem Rust Resistance Genes ◽

Wheat Lines ◽

Rust Resistance Genes

Wheat stem rust, caused byPuccinia granimisf. sp.tritici, severely affects wheat production, but it has been effectively controlled in China since the 1970s. However, the appearance and spread of wheat stem rust races Ug99 (TTKSK, virulence toSr31), TKTTF (virulence toSrTmp) and TTTTF (virulence to the cultivars carryingSr9eandSr13) have received attention. It is important to clarify the effectiveness of resistance genes in a timely manner, especially for the purpose of using new resistance genes in wheat cultivars for durable-resistance. However, little is known about the stem rust resistance genes present in widely used wheat cultivars from Gansu. This study aimed to determine the resistance level at the seedling stage of the main wheat cultivars in Gansu Province. A secondary objective was to assess the prevalence ofSr2,Sr24,Sr25,Sr26,Sr31, andSr38using molecular markers. The results of the present study indicated that 38 (50.7%) wheat varieties displayed resistance to all the tested races ofPuccinia graminisf. sp.tritici.The molecular marker analysis showed that 13 out of 75 major wheat cultivars likely carriedSr2; 25 wheat cultivars likely carriedSr31; and nine wheat cultivars likely carriedSr38. No cultivar was found to haveSr25andSr26, as expected. Surprisingly, no wheat cultivars carriedSr24. The wheat lines with known stem rust resistance genes could be used as donor parent for further breeding programs.

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Pathogenic Variability of Wheat Stem Rust Pathogen (Puccinia graminis f. sp. tritici) in Hararghe Highlands, Ethiopia

Advances in Agriculture ◽

10.1155/2018/8612135 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7

Author(s):

Arif Abrahim ◽

Temam Hussein ◽

Ayele Badebo

Keyword(s):

Resistance Genes ◽

Stem Rust ◽

Agricultural Research ◽

Low Frequency ◽

Puccinia Graminis ◽

Total Production ◽

Rust Disease ◽

Wheat Stem Rust ◽

Pathogenic Variability ◽

Infection Types

Wheat is one of the important major crops of Hararghe Highlands. It is third in land coverage and total production after sorghum and maize. However, the wheat stem rust disease is threatening production of wheat in this region. So, this research was conducted with the following objective: to determine the population of Puccinia graminis f. sp. tritici in Hararghe Highlands. A total of 200 fields were surveyed and stem rust samples were collected and transported to Kulumsa Agricultural Research Center for race analysis. Inoculation of differentials carrying resistance genes Sr24 and Sr-Tmp indicated typical low infection types on all isolates. Isolates EH5, EH8, and EH3 from East Hararghe and WH2, WH1, and WH3 from West Hararghe showed high virulence of infection in all differential lines. Ten (10) races were identified by using Puccinia graminis tritici code system: TTGSK, PTJQK, TTSSK, TTKSK, TRSSK, and TTJQK from East Hararghe and TTTSK and TTSQK from West Hararghe zones. Race TTSSK was most frequent (25%) followed by TTKSK (25%) in East Hararghe. Race TTSSK showed 50% frequency of occurrence in West Hararghe zones. The low frequency of occurrences indicated high variability of the races in the survey areas. Therefore, monitoring of populations of pathogens is important for the national and regional research centers. Detection of pathogen virulence evolution and of currently effective resistance genes is necessary and must be applied within a system of resistance gene management.

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