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

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.

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

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 317-317 ◽  
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.

scholarly journals Resistance of Aegilops Species from Israel to Widely Virulent African and Israeli Races of the Wheat Stem Rust Pathogen

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1309-1320 ◽  
Author(s):  
Jeness C. Scott ◽  
Jacob Manisterski ◽  
Hanan Sela ◽  
Pnina Ben-Yehuda ◽  
Brian J. Steffenson
Keyword(s):  
Stem Rust ◽  
High Frequency ◽  
Infection Type ◽  
Low Frequency ◽  
Puccinia Graminis ◽  
Aegilops Species ◽  
Wheat Stem Rust ◽  
Transfer Resistance ◽  
Desert Region ◽  
Rust Pathogen

Widely virulent races of the stem rust pathogen (Puccinia graminis f. sp. tritici) such as those isolated from Africa (e.g., TTKSK, isolate synonym Ug99) threaten wheat production worldwide. To identify Aegilops accessions with effective resistance to such virulent stem rust races, up to 10 different species from Israel were evaluated against African races TTKSK, TTKST, and TTTSK and the Israeli race TTTTC as seedlings in the greenhouse. A wide diversity of stem rust reactions was observed across the Aegilops spp. and ranged from highly resistant (i.e., infection type 0) to highly susceptible (infection type 4). The frequency of resistance within a species to races TTTTC and TTKSK ranged from 7 and 14%, respectively, in Aegilops searsii to 98 and 100% in AE. speltoides. In all, 346 accessions were found resistant to the three African races and 138 accessions were resistant (or heterogeneous with a resistant component) to all four races. The species with broadly resistant accessions included Ae. longissima (59 accessions), Ae. peregrina (47 accessions), Ae. sharonensis (15 accessions), Ae. geniculata (9 accessions), Ae. kotschyi (5 accessions), and Ae. bicornis (3 accessions). Few geographical trends or correlations with climatic variables were observed with respect to stem rust resistance in the Aegilops spp. The exception was Ae. longissima infected with race TTTTC, where a high frequency of resistance was found in central and northern Israel and a very low frequency in southern Israel (Negev desert region). This geographical trend followed a pattern of annual precipitation in Israel, and a significant correlation was found between this variable and resistance in Ae. longissima. Although difficult, it is feasible to transfer resistance genes from Aegilops spp. into wheat through conventional wide-crossing schemes or, alternatively, a cloning and transformation approach. The broadly resistant accessions identified in this study will be valuable in these research programs.

scholarly journals Pathogenic Variability of Puccinia coronata f. sp. avenae and P. graminis f. sp. avenae on Oat in South Africa

Plant Disease ◽  
2001 ◽  
Vol 85 (10) ◽  
pp. 1085-1090 ◽  
Author(s):  
B. D. van Niekerk ◽  
Z. A. Pretorius ◽  
W. H. P. Boshoff
Keyword(s):  
South Africa ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Stem Rust ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Puccinia Graminis ◽  
Wild Oat ◽  
Low Frequencies ◽  
Pathogenic Variability

Although crown rust (caused by Puccinia coronata f. sp. avenae) and stem rust (caused by Puccinia graminis f. sp. avenae) are generally considered to be the most widespread and damaging diseases of oat (Avena spp.) in South Africa, pathogenic variability has never been studied. During 1997 and 1998, one dominant crown rust pathotype (SBLL) was identified with virulence to resistance genes Pc40, Pc45, Pc46, Pc51, and Pc54. Four other pathotypes (SGLL, PBBB+Pc35, SDQL, and JBBM+Pc35), occurring at low frequencies and further rendering resistance genes Pc35, Pc39, Pc48, Pc50, Pc52, and Pc64 ineffective, were also detected. Resistance gene Pc40 was postulated in Wisconsin X1588-2; Pc51 in Euro, Maluti, Overberg, OX88I 075-106, Perdeberg, and Swartberg; and Pc39 was confirmed in the cultivar Fidler. During the same period, four stem rust pathotypes were identified with virulence to resistance genes Pg1, Pg2, Pg4, Pg8, Pg9, Pg12,Pg15, and Pga. Resistance gene Pga was postulated in Alpha, OX87 080-1, OX88I 075-106, Sederberg, and W94/4; Pg2 and/or Pg4 in Euro, Perdeberg, Potberg, and Swartberg; and Pg9 in Pallinup and Victorian. Collections of wild oat species Avena fatua, A. byzantina, A. sterilis, and A. barbata were susceptible to all crown rust patho-types, while the four stem rust pathotypes were virulent on all species except A. barbata.

scholarly journals Detection of Virulence to Wheat Stem Rust Resistance Gene Sr31 in Puccinia graminis. f. sp. tritici in Uganda

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 203-203 ◽  
Author(s):  
Z. A. Pretorius ◽  
R. P. Singh ◽  
W. W. Wagoire ◽  
T. S. Payne
Keyword(s):  
South African ◽  
Stem Rust ◽  
Rust Resistance ◽  
The United States ◽  
Chromosome Translocation ◽  
Research Station ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Light Mineral ◽  
Infection Types

In much of the world, resistance to stem rust in wheat, caused by Puccinia graminis f. sp. tritici, is based at least in part on the gene Sr31. During February 1999, high levels of stem rust infection were observed on entries in wheat (Triticum aestivum) grown in a nursery at Kalengyere Research Station in Uganda. Because several of the rusted entries were known to carry the 1BL-1RS chromosome translocation containing the Sr31, Lr26, and Yr9 genes for rust resistance, virulence to Sr31 was suspected. Urediniospores, collected in bulk from rusted stems of seven entries containing Sr31, were suspended in light mineral oil and sprayed on primary leaves of 7-day-old seedlings of South African wheat cv. Gamtoos (=Veery #3, pedigree: Kvz/Buho‘S’//Kal/BB). Plants were kept overnight at 19 to 21°C in a dew chamber before placement in a greenhouse at 18 to 25°C. After ≈14 days, urediniospores were collected from large, susceptible-type stem rust pustules and subsequently increased on Gamtoos, which served as a selective host for the new rust culture, designated Pgt-Ug99. Pathogenicity of Pgt-Ug99 was studied in seedling tests of available wheats containing Sr31, as well as other stem rust differential lines. All seedling tests were conducted at least three times in independent inoculations. Isolate Pgt-Ug99 was not virulent to Avocet‘S’/Yr9 (Australian line containing Sr26) or Oom Charl (South African cultivar) but was virulent to the other Sr31 testers: Alondra ‘S’, Bobwhite, Chokka, Clement, Federation/Kavkaz, Gamtoos, Grebe, Kavkaz, Letaba, Line E/Kavkaz, RL6078, and Veery ‘S’. Virulence to Sr31 (infection types [ITs] 3-3 to 3++4) was clearly contrasted by the low reactions (ITs 0; to 1) produced by UVPgt53, a South African pathotype avirulent to Sr31. According to the reactions of the differential lines, Pgt-Ug99 is avirulent to Sr21, -22, -24, -25, -26, -27, -29, -32, -33, -34, -35, -36, -39, -40, -42, and -43, Agi, and Em and virulent to Sr5, -6, -7b, -8a, -8b, -9b, -9e, -9g, -11, -15, -17, -30, -31, and -38. Virulence to the T. ventricosum-derived gene Sr38, which is linked to Lr37 and Yr17 and occurs in cultivars from Australia, the United Kingdom, and the United States, was not known previously (1). Both Pgt-Ug99 and UVPgt53 produced a continuum of ITs (; to 2+3) on Petkus rye (obtained from the USDA-ARS National Small Grains Collection, Aberdeen, ID), the original Sr31 donor source. Pgt-Ug99 did not appear more virulent than UVPgt53 on Petkus. All triticales tested, as well as oat cv. Overberg, were highly resistant to Pgt-Ug99. According to McIntosh et al. (1), Huerta-Espino mentioned a Sr31-virulent culture from Turkey, but this could not be confirmed. Should the Sr31-virulent pathotype migrate out of Uganda, it poses a major threat to wheat production in countries where the leading cultivars have resistance based on this gene. Reference: (1) R. A. McIntosh et al. 1995. Wheat Rusts: An Atlas of Resistance Genes. Kluwer Academic Publishers, Dordrecht, the Netherlands.

scholarly journals Identification of Resistance to Races of Puccinia graminis f. sp. tritici with Broad Virulence in Triticale (×Triticosecale)

Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 479-484 ◽  
Author(s):  
P. D. Olivera ◽  
Z. A. Pretorius ◽  
A. Badebo ◽  
Y. Jin
Keyword(s):  
South African ◽  
Stem Rust ◽  
Triticum Turgidum ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Cereal Rye ◽  
Infection Types ◽  
Stem Rust Resistance Genes ◽  
Moderately Resistant ◽  
Excellent Source

Triticale (×Triticosecale), an amphiploid of wheat (mainly Triticum turgidum) and cereal rye (Secale cereale), is an excellent source of resistance to wheat stem rust, caused by Puccinia graminis f. sp. tritici. A collection of 567 triticale accessions originating from 21 countries was evaluated at the seedling stage for reaction to races of P. graminis f. sp. tritici with broad virulence, including TTKSK, TRTTF, and TTTTF. A high frequency (78.4%) of accessions was resistant to race TTKSK, with low infection types ranging from 0; to X. A selection of 353 TTKSK-resistant accessions was evaluated for reaction to three South African isolates of P. graminis f. sp. tritici with single and/or combined virulences to stem rust resistance genes SrSatu, Sr27, and SrKw present in triticale. Genes SrSatu, Sr27, and SrKw were postulated to be present in 141 accessions and contributed to TTKSK resistance. The remaining 212 resistant accessions may possess uncharacterized genes or combinations of known genes that could not be determined with these isolates. These accessions were further evaluated for resistance to races TTKST, TPMKC, RKQQC, RCRSC, QTHJC, QCCSM, and MCCFC. Resistance remained effective across the entire set of races in the majority of the accessions (n = 200), suggesting that the resistances are effective against a broad spectrum of virulence. In all, 129 (79.6%) resistant accessions with noncharacterized genes were resistant to moderately resistant in field stem rust nurseries at Debre Zeit (Ethiopia) and St. Paul (Minnesota). Results from evaluating F2 populations derived from resistant–susceptible crosses revealed that resistance to TTKSK in triticale was conferred mostly by single genes with dominant effects.

scholarly journals Races of Puccinia graminis Identified in the United States During 2003

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1125-1127 ◽  
Author(s):  
Y. Jin
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
The United States ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Stem Rust Resistance Genes ◽  
Rust Resistance Genes

Stem rust of small grain cereals, caused by Puccinia graminis, is a major disease of wheat, barley, and oat. In order to effectively utilize stem rust resistance in the improvement of small grain cereals, it is necessary to monitor the virulence composition and dynamics in the stem rust population. Races of P. graminis from barberry, wheat, barley, and oat were surveyed across the United States during 2003. Aecial infections on barberry were primarily due to P. graminis f. sp. secalis, as inoculations using aeciospores failed to produce infection on wheat and oat. Race QFCS of P. graminis f. sp. tritici was the most common race identified from wheat and barley. Race QFCS has virulence on stem rust resistance genes Sr5, 8a, 9a, 9d, 9g, 10, 17, and 21 that are used for race identification. Race TTTT was identified in 2003. This race possesses virulence to all 16 stem rust resistance genes present in the wheat stem rust differentials and should be targeted in breeding for stem rust resistance. Race QFCN appeared to be a new race in the U.S. stem rust population. Races QCCJ and MCCF were identified, but at low frequencies. Seven races of P. graminis f. sp. avenae were identified from oat, and races NA-27, NA-29, and NA-67 were the predominant races. Race NA-76 was identified for the first time in the United States.

scholarly journals The wheat Sr22, Sr33, Sr35 and Sr45 genes confer resistance against stem rust in barley

2018 ◽  
Author(s):  
M. Asyraf Md. Hatta ◽  
Ryan Johnson ◽  
Oadi Matny ◽  
Mark A. Smedley ◽  
Guotai Yu ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Puccinia Hordei ◽  
Puccinia Graminis ◽  
Golden Promise ◽  
Wheat Stem Rust ◽  
Potential Source ◽  
Barley Leaf

SummaryIn the last 20 years, stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt), has re-emerged as a major threat to wheat and barley cultivation in Africa and Europe. In contrast to wheat with 82 designated stem rust (Sr) resistance genes, barley’s genetic variation for stem rust resistance is very narrow with only seven resistance genes genetically identified. Of these, only one locus consisting of two genes is effective against Ug99, a strain of Pgt which emerged in Uganda in 1999 and has since spread to much of East Africa and parts of the Middle East. The objective of this study was to assess the functionality, in barley, of cloned wheat Sr genes effective against Ug99. Sr22, Sr33, Sr35 and Sr45 were transformed into barley cv. Golden Promise using Agrobacterium-mediated transformation. All four genes were found to confer effective stem rust resistance. The barley transgenics remained susceptible to the barley leaf rust pathogen Puccinia hordei, indicating that the resistance conferred by these wheat Sr genes was specific for Pgt. Cloned Sr genes from wheat are therefore a potential source of resistance against wheat stem rust in barley.

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

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 784-784 ◽  
Author(s):  
Z. A. Pretorius ◽  
C. M. Bender ◽  
B. Visser ◽  
T. Terefe
Keyword(s):  
South Africa ◽  
South African ◽  
Resistance Genes ◽  
Stem Rust ◽  
Single Step ◽  
Current Evidence ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Wheat Stem Rust ◽  
Kwazulu Natal

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.

scholarly journals 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 Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1096-1099 ◽  
Author(s):  
Y. Jin ◽  
R. P. Singh ◽  
R. W. Ward ◽  
R. Wanyera ◽  
M. Kinyua ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Plant Infection ◽  
Infection Types ◽  
Sr Genes ◽  
Seedling Infection

Stem rust, caused by Puccinia graminis f. sp. tritici, historically was one of the most destructive diseases of wheat and barley. The disease has been under effective control worldwide through the widespread use of host resistance. A number of stem rust resistance genes in wheat have been characterized for their reactions to specific races of P. graminis f. sp. tritici. Adult plant responses to race TTKS (also known as Ug99) of monogenic lines for Sr genes, a direct measurement of the effectiveness for a given gene, have not been investigated to any extent. This report summarizes adult plant infection responses and seedling infection types for monogenic lines of designated Sr genes challenged with race TTKS. High infection types at the seedling stage and susceptible infection responses in adult plants were observed on monogenic lines carrying Sr5, 6, 7a, 7b, 8a, 8b, 9a, 9b, 9d, 9g, 10, 11, 12, 15, 16, 17, 18, 19, 20, 23, 30, 31, 34, 38, and Wld-1. Monogenic lines of resistance genes Sr13, 22, 24, 25, 26, 27, 28, 32, 33, 35, 36, 37, 39, 40, 44, Tmp, and Tt-3 were effective against TTKS both at the seedling and adult plant stages. The low infection types to race TTKS observed for these resistance genes corresponded to the expected low infections of these genes to other incompatible races of P. graminis f. sp. tritici. The level of resistance conferred by these genes at the adult plant stage varied between highly resistant to moderately susceptible. The results from this study were inconclusive for determining the effectiveness of resistance genes Sr9e, 14, 21, and 29 against race TTKS. The understanding of the effectiveness of individual Sr genes against race TTKS will facilitate the utilization of these genes in breeding for stem rust resistance in wheat.

Wheat stem rust in Australia dash 1969-1985

1992 ◽  
Vol 43 (3) ◽  
pp. 399 ◽  
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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