scholarly journals Identification of New Sources of Resistance to Wheat Stem Rust in Aegilops spp. in the Tertiary Genepool of Wheat

2018 ◽  
Vol 9 ◽  
Author(s):  
Pablo D. Olivera ◽  
Matthew N. Rouse ◽  
Yue Jin
Keyword(s):  
Stem Rust ◽  
Sources Of Resistance ◽  
Wheat Stem Rust

scholarly journals Sources of Resistance to Stem Rust Race Ug99 in Spring Wheat Germplasm

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 762-766 ◽  
Author(s):  
M. N. Rouse ◽  
R. Wanyera ◽  
P. Njau ◽  
Y. Jin
Keyword(s):  
Spring Wheat ◽  
Resistance Genes ◽  
North American ◽  
Stem Rust ◽  
Wheat Breeding ◽  
Field Resistance ◽  
Eastern Africa ◽  
Adult Plant ◽  
Sources Of Resistance ◽  
Wheat Stem Rust

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.

scholarly journals Genetic Characterization of Resistance to Wheat Stem Rust Race TTKSK in Landrace and Wild Barley Accessions Identifies the rpg4/Rpg5 Locus

2015 ◽  
Vol 105 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Bullo Erena Mamo ◽  
Kevin P. Smith ◽  
Robert S. Brueggeman ◽  
Brian J. Steffenson
Keyword(s):  
Stem Rust ◽  
Incubation Temperature ◽  
Wild Barley ◽  
Bulked Segregant Analysis ◽  
Single Gene ◽  
Temperature Sensitive ◽  
Resistance Locus ◽  
Sources Of Resistance ◽  
Wheat Stem Rust ◽  
Barley Landraces

Race TTKSK of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici) threatens the production of wheat and barley worldwide because of its broad-spectrum virulence on many widely grown cultivars. Sources of resistance against race TTKSK were recently identified in several barley landraces (Hordeum vulgare subsp. vulgare) and wild barley accessions (H. vulgare subsp. spontaneum). The objectives of this study were to characterize the inheritance of resistance to wheat stem rust race TTKSK in four barley landraces (Hv501, Hv545, Hv602, and Hv612) and two wild barley (WBDC213 and WBDC345) accessions, map the resistance genes, and determine the allelic relationships among the genes in these accessions and the previously described rpg4/Rpg5 locus. Resistant accessions were crossed with the susceptible cv. Steptoe and resulting F3 populations were evaluated for resistance to race TTKSK at the seedling stage. Segregation of F3 families in populations involving the resistance sources of Hv501, Hv545, Hv612, WBDC213, and WBDC345 fit a 1:2:1 ratio for homozygous resistant (HR)/segregating (SEG)/homozygous susceptible (HS) progenies (with χ2 = 2.27 to 5.87 and P = 0.053 to 0.321), indicating that a single gene confers resistance to race TTKSK. Segregation of F3 families in cross Steptoe/Hv602 did not fit a 1:2:1 ratio (HR/SEG/HS of 20:47:43 with χ2 = 11.95 and P = 0.003), indicating that more than one gene is involved in imparting resistance to race TTKSK. Bulked segregant analysis using >1,500 single-nucleotide polymorphism markers positioned a resistance locus in all six populations on chromosome 5HL in very close proximity to the known location of the rpg4/Rpg5 complex locus. Allelism tests were conducted by making crosses among resistant accessions Hv501, Hv545, and Hv612 and also Q21861 with the rpg4/Rpg5 complex. No segregation was observed in F2 families inoculated with race TTKSK, demonstrating that all Hv lines carry the same allele for resistance and that it resides at or very near the rpg4/Rpg5 locus. Phenotype evaluations of the six barley accessions with wheat stem rust race QCCJ revealed resistant infection types (ITs) at a low incubation temperature and susceptible ITs at a high incubation temperature, similar to Q21861, which carries the temperature-sensitive gene rpg4. The accessions also exhibited low ITs against the rye stem rust isolate 92-MN-90, suggesting that they also carry Rpg5. This result was confirmed through molecular analysis, which revealed that all six barley accessions contain the serine threonine protein kinase domain that confers Rpg5 resistance. These results indicate that cultivated barley is extremely vulnerable to African stem rust races such as TTKSK because even these diverse selections of landrace and wild barley accessions carry only one locus for resistance.

SOURCES OF RESISTANCE TO NORTH CAUCASIAN STEM RUST POPULATION AMONG SOFT WHEAT SAMPLES FROM THE ALL-RUSSIAN PLANT RESEARCH INSTITUTE COLLECTION

1970 ◽  
pp. 50-53
Author(s):  
G. V. Volkova ◽  
О. О. Miroshnichenko ◽  
Е. V. Gladkova ◽  
А. V. Dement’ev ◽  
Е. V. Zuev
Keyword(s):  
Stem Rust ◽  
Plant Genetic Resources ◽  
Triticum Aestivum L ◽  
Soft Wheat ◽  
Artificial Infection ◽  
Sources Of Resistance ◽  
Wheat Stem Rust ◽  
The North ◽  
Resistant Varieties ◽  
Russian Plant

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).

SOURCES OF RESISTANCE TO WHEAT STEM RUST IN EAST AFRICA

1969 ◽  
Vol 49 (6) ◽  
pp. 649-654 ◽  
Author(s):  
L. E. Evans ◽  
J. W. Martens ◽  
G. J. Green ◽  
E. A. Hurd
Keyword(s):  
East Africa ◽  
Resistance Gene ◽  
Stem Rust ◽  
Gene Pool ◽  
Wheat Cultivars ◽  
Good Resistance ◽  
Sources Of Resistance ◽  
Wheat Stem Rust

The stem rust reactions in the field and greenhouse of 38 wheat cultivars previously selected for resistance in Kenya are presented. A group of these cultivars had good resistance to the main races found in Canada. The cultivars appear to have a diversity of types of resistance, and there is evidence that their resistance results from the action of genes not previously identified. The 38 cultivars constitute a resistance gene pool that should facilitate the breeding of wheat cultivars resistant to stem rust in Kenya.

scholarly journals Identification of Resistance Sources to Wheat Stem Rust from Introduced Genotypes in Kenya

2017 ◽  
Vol 9 (2) ◽  
pp. 73
Author(s):  
Molly O. Akello ◽  
Felister Nzuve ◽  
Florence Olubayo ◽  
Godwin Macharia ◽  
James Muthomi
Keyword(s):  
Plant Height ◽  
Stem Rust ◽  
Agronomic Traits ◽  
Negative Relationship ◽  
Kernel Weight ◽  
Sources Of Resistance ◽  
Wheat Stem Rust ◽  
Progress Curve ◽  
Rust Severity ◽  
Infection Types

Stem rust Puccinia graminis Pers. f. sp. tritici of wheat is the most important disease in Kenya. Emergence of race Ug99 and other variants virulent to host resistance genes including Sr31 has rendered 95% of Kenyan cultivars susceptible. This study aimed to identify new sources of resistance to stem rust in a collection of exotic genotypes. Three hundred and sixteen wheat genotypes were screened at the Kenya Agricultural and Livestock Research Organization (KALRO) in Njoro for two seasons in 2015. The host reaction to disease was evaluated based on the modified Cobb scale. The relative Final Rust Severity (rFRS), Average Coefficient of Infection (ACI) and relative Area Under Disease Progress Curve (rAUDPC) were used to characterize the genotypes for stem rust resistance. Agronomic traits were also recorded. Six genotypes namely ALBW-100, ALBW- 204, EPCBW-261, EPCBW-295, PCHP-309 and PCHPBW-310 with significantly low ACI, rAUDPC and rFRS were identified. Thirty five genotypes showed Pseudo-Black Chaff (PBC) phenotype associated with resistant gene Sr2, a source of partial resistance in wheat. The genotypes also showed low disease severity (20-25%) and Moderately Susceptible (MS) – Susceptible (S) infection types in both seasons. Genotypes had significant differences (p ≤ 0.05) on plant height, 1000-kernel weight and number of tillers indicating genetic variation which could be exploited in breeding for resistance to stem rust. The negative relationship between agronomic variables involving plant height, spikelet length and 1000-kernel weight showed harmful effects of stem rust on plant characteristics including yield. The stem rust resistant genotypes with good agronomic traits could be introgressed into adapted Kenyan backgrounds while the genotypes showing presence of PBC could be utilized to develop durable stem rust resistant wheat. Inheritance studies to elucidate the exact genes conferring resistance to stem rust could be conducted for breeders to exploit their genetic variability.

scholarly journals Virulence and race structure of Puccinia graminis f. sp. tritici in Kazakhstan

2020 ◽  
Vol 56 (No. 4) ◽  
pp. 275-284
Author(s):  
Aralbek Rsaliyev ◽  
Gulbahar Yskakova ◽  
Akerke Maulenbay ◽  
Kunsulu Zakarya ◽  
Shynbolat Rsaliyev
Keyword(s):  
Stem Rust ◽  
Wheat Breeding ◽  
Puccinia Graminis ◽  
Sources Of Resistance ◽  
Wheat Stem Rust ◽  
East Kazakhstan ◽  
Breeding Programmes ◽  
Stem Rust Resistance Genes ◽  
Rust Resistance Genes ◽  
Virulence Diversity

Severe epidemics of wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) have been observed in recent years in major spring wheat producing regions in Kazakhstan. However, information on the virulence structure and race composition of Pgt is currently not available. Stem rust samples were collected in 2015–2018 in three regions of Kazakhstan to determine the virulence diversity and race distribution in the Pgt populations. A total of 203 single-pustule isolates were derived and evaluated on the stem rust differential and supplemental lines and 38 races were identified. Among them, the races QHHSF and THMTF were found in all the regions and in all the years. The races RFRTF, RHMRF, TKRPF and MHCTC were the most common races in the Akmola and Kostanay regions, and the races LHCSF, QKCSF and LKCSF were only widely distributed in East Kazakhstan. The virulence complexity (i.e., number of Sr genes on which the races were virulent) ranged from 5 to 16, with about 40% of the races having 14 or more virulence. The stem rust resistance genes Sr11, Sr13, Sr22, Sr26, Sr31, Sr33 and Sr35 were found to confer resistance to all the races identified during the study period. Hence, these genes can be used as sources of resistance in wheat breeding programmes in Kazakhstan.

Retrospective analysis of virulence of the North Caucasian population of wheat stem rust pathogen

2019 ◽  
Vol 1 (81) ◽  
pp. 85-90
Author(s):  
Galina Volkova ◽  
◽  
Olesya Miroshnichenko ◽  
Olga Tarancheva ◽  
◽  
...  
Keyword(s):  
Retrospective Analysis ◽  
Stem Rust ◽  
Caucasian Population ◽  
Wheat Stem Rust ◽  
The North ◽  
Rust Pathogen
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