PHYSIOLOGIC SPECIALIZATION IN OAT STEM RUST IN CANADA FROM 1944 TO 1959

1961 ◽  
Vol 41 (1) ◽  
pp. 153-165 ◽  
Author(s):  
G. J. Green ◽  
T. Johnson ◽  
J. N. Welsh

Annual physiologic race surveys of oat stem rust have shown that races 1, 2, and 5 predominated in Canada from 1921 to 1944; races 8, 10, and 11 from 1945 to 1952; and races 3, 7, and 12 from 1953 to 1959. The increased prevalence of races 8, 10, and 11 led to increased rusting of the rust-resistant varieties produced in Canada between 1937 and 1941. The increased prevalence of races 3, 7, and 12 was of little economic significance because these varieties were resistant to this group of races. Race 7A, which differs from other cultures of race 7 in being virulent on Rodney, has increased slowly but steadily since its discovery in 1952. Races 6A, 8A, 11A, and 13A which are virulent on Garry as well as Rodney have been found in eastern Ontario and Quebec. The "A" signifies virulence on the variety Rodney which is resistant to earlier cultures of races 6, 7, 8, 11, and 13. Race 6A is virulent on varieties with any or all of the resistance genes A, BC, D, and E. These are the only genes for resistance to stem rust carried by present-day varieties that are grown commercially in Canada. Several sources of resistance to these new and dangerous races have been found. The variety C.I. 4023 appears to have outstanding resistance.

2018 ◽  
Vol 29 (1) ◽  
pp. 19 ◽  
Author(s):  
Diego Rodríguez-Ortega ◽  
Laura Vega-Jiménez ◽  
Ángel Rubén Murillo-Ilbay ◽  
Eduardo Peralta-Idrovo ◽  
Juan Carlos Rosas-Sotomayor

Anthracnose caused by Colletotrichum lindemuthianum is one of the most economically important diseases of bean (Phaseolus vulgaris L.) cultivation in Ecuador. The best control alternative is the use of resistant varieties. C. lindemuthianum presents great pathogenic variability, which hinders the development of varieties with a lasting resistance, therefore, the knowledge of the presence and distribution of the physiological races of the pathogen and the identification of resistance genes are key to developing varieties with broad and lasting resistance. The objective of this research was to determine the pathogenic variability of C. lindemuthianum and to evaluate the resistance of Ecuadorian bean germplasm. The research was carried out between 2013 and 2014. Seventeen isolates of C. lindemuthianum from northern central Ecuador were characterized by the inoculation of a group of twelve standard differential bean varieties. Among the analyzed samples, thirteen races were identified; five of those races had not been previously reported in the country. The differential G2333 (Co-42, Co-52 and Co-7) presented resistance to every characterized races in Ecuador. In addition, twenty - one improved varieties and elite bean lines were evaluated with sixteen of the seventeen isolates, three genotypes were identified (TB2, TB3 and INIAP 485 Urcuquí) with resistance to the mentioned isolates, which can be used as sources of resistance to Anthracnose. The identified sources of resistance in this study will allow to plan the development of bean varieties with broad and durable resistance to C. lindemuthianum.


1964 ◽  
Vol 44 (5) ◽  
pp. 418-426 ◽  
Author(s):  
G. J. Green ◽  
R. I. H. McKenzie

New races of oat stem rust that can attack varieties carrying all identified resistance genes were found in Canada between 1957 and 1963. Varieties moderately resistant to some of these races have been found, but they are susceptible to other less-prevalent races. Some of the sources of resistance are: Ukraine, C.I. 3259; Ark. 674(2)-39-F, C.I. 4529; C.I. 4673; C.I. 5109; Santa Fe Selection, C.I. 5844; C.I. 6792; Silva No. 1729-49-1, C.I. 6849; and Rosen’s Mutant. White Russian (gene D) and Sevnothree (gene E) were resistant in the adult plant stage to one culture of race 6AF, although susceptible in the seedling stage.


Plant Disease ◽  
2016 ◽  
Vol 100 (6) ◽  
pp. 1101-1109 ◽  
Author(s):  
Mahbubjon Rahmatov ◽  
Matthew N. Rouse ◽  
Brian J. Steffenson ◽  
Staffan C. Andersson ◽  
Ruth Wanyera ◽  
...  

Stem rust is one of the most devastating diseases of wheat. Widely virulent races of the pathogen in the Ug99 lineage (e.g., TTKSK) are threatening wheat production worldwide; therefore, there is an urgent need to enhance the diversity of resistance genes in the crop. The objectives of this study were to identify new sources of resistance in wheat-alien introgression derivatives from Secale cereale, Leymus mollis, L. racemosus, and Thinopyrum junceiforme, postulate genes conferring the resistance, and verify the postulated genes by use of molecular markers. From seedling tests conducted in the greenhouse, the presence of seven known stem rust resistance genes (Sr7b, Sr8a, Sr9d, Sr10, Sr31, Sr36, and SrSatu) was postulated in the wheat-alien introgression lines. More lines possessed a high level of resistance in the field compared with the number of lines that were resistant at the seedling stage. Three 2R (2D) wheat-rye substitution lines (SLU210, SLU238, and SLU239) seemed likely to possess new genes for resistance to stem rust based on their resistance pattern to 13 different stem rust races but the genes responsible could not be identified. Wheat-rye, wheat-L. racemosus, and wheat-L. mollis substitutions or translocations with single and multiple interchanges of chromosomes, in particular of the B and D chromosomes of wheat, were verified by a combination of genomic in situ hybridization and molecular markers. Thus, the present study identified novel resistance genes originating from different alien introgressions into the wheat genome of the evaluated lines. Such genes may prove useful in enhancing the diversity of stem rust resistance in wheat against widely virulent pathogen races such as those in the Ug99 lineage.


1970 ◽  
Vol 48 (5) ◽  
pp. 969-975 ◽  
Author(s):  
J. W. Martens ◽  
R. I. H. McKenzie ◽  
G. J. Green

The results of 48 years of oat stem rust physiologic race surveys are interpreted in terms of the prevailing host genotype. Changes in the frequencies of genes that govern virulence in the pathogen can be explained only in part by changes in the resistance genes carried by the host population. Genes for virulence on newly released types of resistance have spread very quickly through the rust population, after initial 'breakdown' of the resistance. The most successful physiologic races carry genes for virulence in excess of those required for successful parasitism in North America. Many races carry genes for virulence on types of resistance that have never been used on this continent.


2019 ◽  
Author(s):  
Erena A. Edae ◽  
Matthew N. Rouse

AbstractMany disease resistance genes that have been transferred from wild relatives to cultivated wheat have played a significant role in wheat production worldwide. Ae. umbellulata is one of the species within the genus Aegilops that have been successfully used as sources of resistance genes to leaf rust, stem rust and powdery mildew. The objectives of the current work was to validate the map position of a major QTL that confers resistance to the stem rust pathogen races Ug99 (TTKSK) and TTTTF with an independent bi-parental mapping population and to refine the QTL region with a bulk segregant analysis approach. Two F2 bi-parental mapping populations were developed from stem rust resistant Ae. umbellulata accessions (PI 298905 and PI 5422375) and stem rust susceptible accessions (PI 542369 and PI 554395). Firstly, one of the two populations was used to map the chromosome location of the resistance gene. Later on, the 2nd population was used to validate the chromosome location in combination with a bulk segregant analysis approach. For the bulk segregant analysis, RNA was extracted from a bulk of leaf tissues of 12 homozygous resistant F3 families, and a separate bulk of 11 susceptible homozygous F3 families derived from the PI 5422375 and PI 554395 cross. The RNA samples of the two bulks and the two parents were sequenced for SNPs identification. Stem rust resistance QTL was validated on chromosome 2U of Ae. umbellulata in the same region in both populations. With bulk segregant analysis, the QTL position was delimited within 3.2 Mbp. Although there were a large number of genes in the orthologous region of the detected QTL on chromosome 2D of Ae. tauschii, we detected only two Ae. umbellulata NLR genes which can be considered as a potential candidate genes.


2016 ◽  
Vol 52 (No. 4) ◽  
pp. 242-249 ◽  
Author(s):  
Li Tian-ya ◽  
Wu Xian-xin ◽  
Xu Xiao-feng ◽  
Wang Wan-lin ◽  
Cao Yuan-yin

To determine stem rust resistance genes of wheat varieties in Yunnan province, 11 Chinese strains of Puccinia graminis f.sp. tritici with different virulence and 1 artificial mutant strain were used in 110 wheat varieties. The results indicated that among the 45 Sr genes, Sr31, Sr5, SrTmp, Sr30, Sr36, Sr8a, Sr11, Sr24, Sr29, Sr34, Sr9e, Sr26, Sr38, Sr47, and SrTt3 were characterised in 55 wheat varieties singly or in combination. Sr5, Sr31, SrTmp, Sr36, and Sr30 were contained in 17, 16, 5, 5, and 3 cultivars, respectively. Six cultivars contained Sr24 and/or Sr34. Three plant materials likely contained one or more of Sr8a, Sr11, Sr34, and Sr23 genes as well as other unknown genes. The 16 immune or highly resistant varieties contained one or more of Sr9e, Sr26, Sr38, Sr47, SrTt3, and other unknown resistance genes. The reaction types on 22 of the tested cultivars were different from those on Sr genes tested, and their resistance genes could not be analysed. Additionally, 17 varieties were susceptible to all the tested strains, having no postulation value. Our study provides a basis for improved breeding of stem rust resistant wheat in China.


Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 762-766 ◽  
Author(s):  
M. N. Rouse ◽  
R. Wanyera ◽  
P. Njau ◽  
Y. Jin

Wheat stem rust (Puccinia graminis f. sp. tritici) race TTKSK (Ug99), with virulence to the majority of the world's wheat (Triticum aestivum) cultivars, has spread from Uganda throughout eastern Africa, Yemen, and Iran. The identification and spread of variants of race TTKSK with virulence to additional stem rust resistance genes has reminded breeders and pathologists of the danger of deploying major resistance genes alone. In order to protect wheat from this rapidly spreading and adapting pathogen, multiple resistance genes are needed, preferably from improved germplasm. Preliminary screening of over 700 spring wheat breeding lines and cultivars developed at least 20 years ago identified 88 accessions with field resistance to Ug99. We included these resistant accessions in the stem rust screening nursery in Njoro, Kenya for two additional seasons. The accessions were also screened with a bulk of North American isolates of P. graminis f. sp. tritici in the field in St. Paul, MN. In order to further characterize the resistance in these accessions, we obtained seedling phenotypes for 10 races of P. graminis f. sp. tritici, including two races from the race TTKSK complex. This phenotyping led to the identification of accessions with either adult-plant or all-stage resistance to race TTKSK, and often North American races of P. graminis f. sp. tritici as well. These Ug99 resistant accessions can be obtained by breeders and introgressed into current breeding germplasm.


Author(s):  
G. V. Volkova ◽  
О. О. Miroshnichenko ◽  
Е. V. Gladkova ◽  
А. V. Dement’ev ◽  
Е. V. Zuev

Wheat stem rust (pathogen Puccinia graminis Pers. f. sp. tritici) is a dangerous disease that affects crops.  The pathogen causes many ruptures of the epidermis of the stem.  With a significant development of the pathogen, lodging of wheat crops is possible, the yield sharply decreases due to the so-called outflow of grain.  The use of pathogen resistant varieties is one of the most effective wheat protection methods. In 2018-2019, against the background of artificial infection with P. graminis, 263 samples of soft wheat (Triticum aestivum L.) from the collection of the Vavilov All - Russian Institute of Plant Genetic Resources (VIR) were evaluated, of which 186 were spring and 77 were winter. Varieties and lines of soft wheat were represented from 27 countries and mostly from Russia (44.9 % of the number studied). 56 sources of resistance to the North Caucasian population of P. graminis were identified, which are recommended for use in selection for immunity. A larger number of P. graminis-resistant specimens were isolated from Russia – 26 and Canada-9. Of particular interest for breeding are samples of soft wheat that were absolutely resistant to artificial infection with the pathogen: Stolypenskaya 2 (K - 66388, Russia, Omsk region), Grenada (K-66399, Russia, Tyumen region), Primorskaya 50 (K-66409, Russia, Primorsky Krai), Vishivanka (K-65257, Ukraine), K-66443 (Georgia), Shortandinskaya 2014 (K-66424, Kazakhstan), Chi Mai 1 (K-66440, China), byrsa (K-65852, Tunisia), Lovitt (K-66204, Canada), Nil Thatcher Lr35 (K-66207, Canada), Harding (K-66081, USA), Juchi F2000 (K-66252, Mexico).


Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 840-840 ◽  
Author(s):  
S. K. Jain ◽  
M. Prashar ◽  
S. C. Bhardwaj ◽  
S. B. Singh ◽  
Y. P. Sharma

Stem (black) rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks. & Henn., is one of the most destructive diseases of wheat. It could be controlled through introgression of race-specific resistance genes. However, such kind of resistance is mostly short lived due to emergence of new virulences. For example, resistance genes Sr11, Sr24, Sr30, and Sr31 are no longer effective (2,4). Detection of new virulences has remained vital in the evaluation and identification of new sources of resistance. We report here the detection of virulence to Sr25, a gene from Thinopyrum elongatum (4), which had been effective or partially effective against stem rust worldwide, including race Ug99 (TTKSK) (4). A stem rust isolate collected in 2006 from Karnataka (southern India) produced susceptible reactions (infection type [IT] 3+ to 4) on the primary leaves of differential genotype ‘Agatha’ carrying Sr25 and susceptible check ‘Agra Local’ at 22 ± 2°C. To verify virulence to Sr25, single-pustule isolates from this sample were inoculated onto seedlings of ‘Agrus’, ‘Agatha’, ‘RL6040’ (‘Thatcher’ + Sr25), ‘Superseri#1’, ‘Wheatear’, and ‘Morocco’ + Sr25 (obtained from CIMMYT), which all carry Sr25. All these accessions were found susceptible (IT 3+ to 4) to this isolate, except Wheatear which expressed resistance (IT ;1), indicating the presence of additional gene(s). These genotypes are resistant (ITs ;1 to 2+) to Sr25-avirulent pathotypes. The new pathotype is avirulent to Sr11, 13, 14, 21, 22, 23, 24, 26, 27, 29, 31, 32, 33, 35, 37, 38, 39, 40, 43, and Tmp and virulent to Sr5, 6, 7a, 7b, 8a, 9a, 9b, 9d, 9e, 9f, 9g, 10, 12, 15, 16, 17, 18, 19, 20, 25, 28, 30, 34, 36, 42, Wld-1, and Gt at 22 ± 2°C. This pathotype has been designated as 58G13-3 and PKTSC according to the Indian nomenclature (1) and the North American system (3), respectively. It represents race 40 based on Stakman's differentials. It may have arisen from race 40 through mutation. The type culture of the pathotype has been added to the culture collection at Flowerdale, Shimla. Interestingly, ‘Festiguay’ (Sr30) was found resistant to this pathotype, indicating the presence of additional gene(s), whereas ‘Webster’ (Sr30) was susceptible. Adult plants of Agrus, Agatha, RL6040, Superseri#1, and Morocco+Sr25 also were susceptible, producing 20S to 60S responses. Sr25-avirulent pathotype 62G29 produced a TR (flecking in traces) response on these lines except Morocco + Sr25 that showed 20 to 40MR (moderately resistant) responses. In the same study however, adult plants of Thatcher showed a resistant reaction (10R to MR) at low (16 ± 2°C) and susceptible (20S) at high (22 ± 2°C) temperatures. Agatha and RL6040, having Thatcher as one of the parents, had similar responses. The detection of Sr25 virulence is significant since Sr25 is an important gene to be targeted for breeding wheat cultivars resistant to Ug99. We should use either adult plant resistance and/or pyramiding two or more genes for seedling resistance to enhance the field life of wheat cultivars. References: (1) P. Bahadur et al. Proc. Indian Acad. Sci. 95:29, 1985. (2) S. C. Bhardwaj et al. J. Wheat Res. 1:51, 2007. (3) Y. Jin et al. Plant Dis. 92:923, 2008. (4) R. P. Singh et al. CAB Rev. No. 054:1, 2006.


2011 ◽  
Vol 101 (12) ◽  
pp. 1418-1423 ◽  
Author(s):  
M. N. Rouse ◽  
Y. Jin

Race TTKSK (or Ug99) of Puccinia graminis f. sp. tritici possesses virulence to several stem rust resistance genes commonly present in wheat cultivars grown worldwide. New variants detected in the race TTKSK lineage further broadened the virulence spectrum. The identification of sources of genetic resistance to race TTKSK and its relatives is necessary to enable the development and deployment of resistant varieties. Accessions of Triticum monococcum, an A-genome diploid wild and cultivated wheat, have previously been characterized as resistant to stem rust. Three resistance genes were identified and introgressed into hexaploid wheat: Sr21, Sr22, and Sr35. The objective of this study was to determine the genetic control and allelic relationships of resistance to race TTKSK in T. monococcum accessions identified through evaluations at the seedling stage. Generation F2 progeny of 8 crosses between resistant and susceptible accessions and 13 crosses between resistant accessions of T. monococcum were evaluated with race TTKSK and often with North American races, including races QFCSC, TTTTF, and MCCFC. For a selected population segregating for three genes conferring resistance to race TTKSK, F2:3 progeny were evaluated with races TTKSK, QFCSC, and TTTTF. In that population, we detected two genes conferring resistance to race TTKSK that are different from Sr21, Sr22, and Sr35. One of the new genes was effective to all races tested. The identification of these genes will facilitate the development of varieties with new resistance to race TTKSK.


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