scholarly journals The situation of common wheat rusts in the Southern Cone of America and perspectives for control

2007 ◽  
Vol 58 (6) ◽  
pp. 620 ◽  
Author(s):  
Silvia Germán ◽  
Amarilis Barcellos ◽  
Marcia Chaves ◽  
Mohan Kohli ◽  
Pablo Campos ◽  
...  

Approximately 9 million ha of wheat (Triticum aestivum and T. durum) is sown in the Southern Cone of America (Argentina, Brazil, Chile, Paraguay, and Uruguay). Two rust epidemiological zones separated by the Andean mountain range have been described in the region. Presently, leaf rust (caused by Puccinia triticina) is the most important rust disease of wheat. The utilisation of susceptible or moderately susceptible cultivars in a high proportion of the wheat area allows the pathogen to oversummer across large areas, resulting in early onset of the epidemics. Severe epidemics cause important economic losses if chemical control is not used. The pathogen population is extremely dynamic, leading to transitory resistance in commercial cultivars. Lr34 is commonly present in the regional germplasm, but there is limited knowledge about the presence of other genes conferring resistance in cultivars. Genes Lr28, Lr36, Lr38, Lr41, and Lr43 provide effective resistance in the region. The best strategy for the stabilisation of the pathogen population and resistance is considered to be the use of adult plant resistance conferred by minor additive genes including Lr34 and Lr46. Sources of this type of resistance from CIMMYT and the region have been made available to breeding programs in the Southern Cone. Stripe rust (P. striiformis f. sp. tritici) is endemic in Chile where chemical control is required to prevent severe losses in stripe rust susceptible cultivars. Although new virulent races emerge frequently, resistance genes Yr5, Yr8, Yr10, Yr15, and YrSp are currently effective in Chile. Some important stripe rust epidemics have occurred in Argentina, Brazil, and Uruguay. Avoiding the use of highly susceptible cultivars appears to be an effective strategy to prevent stripe rust epidemic development in this area. There have been no serious stem rust (P. graminis f. sp. tritici) epidemics for over 2 decades; the disease was controlled by resistant cultivars. The most important genes conferring resistance in Southern Cone germplasm at the present time are probably Sr24 and Sr31. Other effective genes are Sr22, Sr25, Sr26, Sr32, Sr33, Sr35, Sr39, and Sr40. Several stem rust susceptible wheat cultivars have recently been released. The increased cultivation of susceptible cultivars may lead to higher stem rust incidence, increasing the probability of appearance of new virulent races. Since the 1BL.1RS translocation possessing Sr31 is present in a high proportion of the regional germplasm, the possible introduction of stem rust with Sr31 virulence from Africa is of great concern.


2010 ◽  
Vol 61 (12) ◽  
pp. 1036 ◽  
Author(s):  
J. Zhang ◽  
C. R. Wellings ◽  
R. A. McIntosh ◽  
R. F. Park

Seedling resistances to stem rust, leaf rust and stripe rust were evaluated in the 37th International Triticale Screening Nursery, distributed by the International Wheat and Maize Improvement Centre (CIMMYT) in 2005. In stem rust tests, 12 and 69 of a total of 81 entries were postulated to carry Sr27 and SrSatu, respectively. When compared with previous studies of CIMMYT triticale nurseries distributed from 1980 to 1986 and 1991 to 1993, the results suggest a lack of expansion in the diversity of stem rust resistance. A total of 62 of 64 entries were resistant to five leaf rust pathotypes. In stripe rust tests, ~93% of the lines were postulated to carry Yr9 alone or in combination with other genes. The absence of Lr26 in these entries indicated that Yr9 and Lr26 are not genetically associated in triticale. A high proportion of nursery entries (63%) were postulated to carry an uncharacterised gene, YrJackie. The 13 lines resistant to stripe rust and the 62 entries resistant to leaf rust represent potentially useful sources of seedling resistance in developing new triticale cultivars. Field rust tests are needed to verify if seedling susceptible entries also carry adult plant resistance.



2007 ◽  
Vol 58 (6) ◽  
pp. 567 ◽  
Author(s):  
C. R. Wellings

The wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici; Pst) was first detected in Australia in 1979. The features of the initial pathotype suggested that it was of European origin, and later work provided evidence that it was most likely transmitted as adherent spores on travellers’ clothing. Despite long-held views that this cool temperature pathogen would not adapt to Australian conditions, Pst became endemic and progressively adapted to commercial wheat production through step-wise mutation. Several of these mutant pathotypes became frequent in the Pst population, causing widespread infection and significant costs to production (yield and quality losses; chemical control expenditure) in certain cultivars and seasons. Pathotype evolution, including adaptation to native barley grass (Hordeum spp.) populations, is described. The occurrence of an exotic pathotype of Pst in Western Australia in 2002, and its subsequent spread to eastern Australia, represented a major shift in the pathogen population. This pathotype dominated pathogen populations throughout Australia from 2003, with chemical control expenditure estimated at AU$40–90 million annually. Another exotic introduction was detected in 1998. Initial data indicated that certain isolates collected from barley grass were highly avirulent to wheat differentials, with the exception of partial virulence to Chinese 166. Further seedling tests revealed that these isolates, tentatively designated barley grass stripe rust (BGYR), were virulent on several Australian barleys, notably those of Skiff parentage. Data, including molecular studies, suggest that BGYR is a new forma specialis of P. striiformis. Field nurseries indicate that BGYR is likely to have little impact on commercial barley, although this may change with further pathotype evolution or the release of susceptible cultivars.



2020 ◽  
Vol 110 (5) ◽  
pp. 1082-1092 ◽  
Author(s):  
Javier Hernandez ◽  
Alicia del Blanco ◽  
Tanya Filichkin ◽  
Scott Fisk ◽  
Lynn Gallagher ◽  
...  

Stripe rust (incited by Puccinia striiformis f. sp. hordei) and stem rust (incited by P. graminis f. sp. tritici) are two of the most important diseases affecting barley. Building on prior work involving the introgression of the resistance genes rpg4/Rpg5 into diverse genetic backgrounds and the discovery of additional quantitative trait locus (QTLs) for stem rust resistance, we generated an array of germplasm in which we mapped resistance to stripe rust and stem rust. Stem rust races TTKSK and QCCJB were used for resistance mapping at the seedling and adult plant stages, respectively. Resistance to stripe rust, at the adult plant stage, was determined by QTLs on chromosomes 1H, 4H, and 5H that were previously reported in the literature. The rpg4/Rpg5 complex was validated as a source of resistance to stem rust at the seedling stage. Some parental germplasm, selected as potentially resistant to stem rust or susceptible but having other positive attributes, showed resistance at the seedling stage, which appears to be allelic to rpg4/Rpg5. The rpg4/Rpg5 complex, and this new allele, were not sufficient for adult plant resistance to stem rust in one environment. A QTL on 5H, distinct from Rpg5 and a previously reported resistance QTL, was required for resistance at the adult plant stage in all environments. This QTL is coincident with the QTL for stripe rust resistance. Germplasm with mapped genes/QTLs conferring resistance to stripe and stem rust was identified and is available as a resource to the research and breeding communities.



Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Y. Anikster ◽  
J. Manisterski ◽  
D. L. Long ◽  
K. J. Leonard

A total of 742 single plant accessions of Triticum dicoccoides were collected from 26 locations in Israel. All accessions were evaluated for leaf rust (Puccinia triticina) resistance in field plots at Tel Aviv, and subsets of 284 and 468 accessions were tested in the greenhouse in Tel Aviv and St. Paul, MN, respectively, for seedling resistance to leaf rust; 460 accessions were also tested for seedling resistance to stem rust (Puccinia graminis f. sp. tritici) in St. Paul. One accession was highly resistant to leaf rust in seedling tests in Tel Aviv, and 21 others had moderately susceptible to moderately resistant seedling resistance. Four accessions were highly resistant to leaf rust in seedling tests in St. Paul, and 11 were resistant to at least one stem rust race. Adult resistance to leaf rust was more common than seedling resistance among the accessions; 21 accessions had less than 25% leaf rust severity in field plots compared with 80 to 90% severity for highly susceptible accessions. Most of the accessions with effective adult plant resistance came from two nearby locations in Upper Galilee, a region where populations of T. dicoccoides are most extensive and genetically diverse. These accessions may provide valuable new partial resistance genes for durable protection against leaf rust in cultivated wheat.



Genome ◽  
2005 ◽  
Vol 48 (1) ◽  
pp. 97-107 ◽  
Author(s):  
A Navabi ◽  
J P Tewari ◽  
R P Singh ◽  
B McCallum ◽  
A Laroche ◽  
...  

An F4-derived F6 recombinant inbred line population (n = 148) of a cross between the durable stripe (yellow) rust (caused by Puccinia striiformis) and leaf (brown) rust (caused by Puccinia triticina) resistant cultivar, Triticum aestivum 'Cook', and susceptible genotype Avocet-YrA was phenotyped at several locations in Canada and Mexico under artificial epidemics of leaf or stripe rusts and genotyped using amplified fragment length polymorphism (AFLP) and microsatellite markers. Durable adult plant resistance to stripe and leaf rusts in 'Cook' is inherited quantitatively and was based on the additive interaction of linked and (or) pleiotropic slow-rusting genes Lr34 and Yr18 and the temperature-sensitive stripe rust resistance gene, YrCK, with additional genetic factors. Identified QTLs accounted for 18% to 31% of the phenotypic variation in leaf and stripe rust reactions, respectively. In accordance with the high phenotypic associations between leaf and stripe rust resistance, some of the identified QTLs appeared to be linked and (or) pleiotropic for both rusts across tests. Although a QTL was identified on chromosome 7D with significant effects on both rusts at some testing locations, it was not possible to refine the location of Lr34 or Yr18 because of the scarcity of markers in this region. The temperature-sensitive stripe rust resistance response, conditioned by the YrCK gene, significantly contributed to overall resistance to both rusts, indicating that this gene also had pleiotropic effects.Key words: wheat, rust diseases, Puccinia striiformis, Puccinia triticina, durable resistance, leaf-tip necrosis, QTL analysis.



Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2262
Author(s):  
Ghady E. Omar ◽  
Yasser S. A. Mazrou ◽  
Mohammad K. EL-Kazzaz ◽  
Kamal E. Ghoniem ◽  
Mammduh A. Ashmawy ◽  
...  

Adult plant resistance in wheat is an achievement of the breeding objective because of its durability in comparison with race-specific resistance. Partial resistance to wheat stripe rust disease was evaluated under greenhouse and field conditions during the period from 2016 to 2021. Misr 3, Sakha 95, and Giza 171 were the highest effective wheat genotypes against Puccinia striiformis f. sp. tritici races. Under greenhouse genotypes, Sakha 94, Giza 168, and Shandaweel1 were moderately susceptible, had the longest latent period and lowest values of the length of stripes and infection frequency at the adult stage. Partial resistance levels under field conditions were assessed, genotypes Sakha 94, Giza 168, and Shandaweel1 exhibited partial resistance against the disease. Leaf tip necrosis (LTN) was noted positively in three genotypes Sakha 94, Sakha 95, and Shandaweel1. Molecular analyses of Yr18 were performed for csLV34, cssfr1, and cssfr2 markers. Only Sakha 94 and Shandaweel1 proved to carry the Yr18 resistance allele at both phenotypic and genotypic levels. Scanning electron microscopy (SEM) observed that the susceptible genotypes were colonized extensively on leaves, but on the slow-rusting genotype, the pustules were much less in number, diminutive, and poorly sporulation, which is similar to the pustule of NIL Jupateco73 ‘R’.



2011 ◽  
Vol 47 (Special Issue) ◽  
pp. S155-S159 ◽  
Author(s):  
P.K. Malaker ◽  
M.M.A. Reza

Leaf rust caused by Puccinia triticina is the most important disease among the three rusts of wheat in Bangladesh. The disease occurs in all wheat growing areas of the country with varying degrees of severity. Stem rust caused by P. graminis f.sp. tritici was last observed during the mid 1980s, while yellow rust caused by P. striiformis f.sp. tritici occurs occasionally in the north-western region, where a relatively cooler climate prevails during the winter months. None of the rusts has yet reached an epidemic level, but damaging epidemics may occur in future, particularly if a virulent race develops or is introduced. The genes conferring rust resistance in the breeding lines and wheat varieties released in Bangladesh were investigated at CIMMYT-Mexico and DWR-India. The resistance genes Lr1, Lr3, Lr10, Lr13, Lr23 and Lr26, Sr2, Sr5, Sr7b, Sr8b, Sr9b, Sr11 and Sr31; and Yr2KS and Yr9 were found. An adult plant slow rusting resistance gene Lr34 was also identified in some of the breeding lines and varieties based on the presence of clear leaf tip necrosis under field conditions. Considering the possible risk of migration of the devastating Ug99 race of stem rust into the Indo-Pak subcontinent, the Bangladeshi wheat lines and cultivars are being regularly sent to KARI in Kenya for testing their resistance against this race. The resistant lines have been included in multi-location yield trials and multiplied for future use in order to mitigate the threat of Ug99. The resistant lines have also been included in crossing schemes to develop genetic diversity of rust resistance.



2017 ◽  
Author(s):  
Deepika Narang ◽  
Satinder Kaur ◽  
Jyoti Saini ◽  
Parveen Chhuneja

AbstractA wild non-progenitor species from wheat tertiary gene pool Aegilops peregrina accession pau3519 (UUSS) was used for introgression of leaf rust and stripe rust resistance in bread wheat. It was crossed and backcrossed with hexaploid wheat line Chinese Spring PhI to develop two homozygous BC2F6 wheat-Ae. peregrina introgression lines (ILs) viz. IL pau16058 and IL pau16061 through induced homoeologous recombination. Homozygous lines were screened against six Puccinia triticina and two Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. IL pau16061 showed resistance to leaf rust only while IL pau16058 was resistant to both leaf and stripe rust pathotypes throughout plant life. Molecular characterization of these ILs aided in defining the introgressed regions. Identification of linked markers with advance genomic technologies will aid in marker assisted pyramiding of alien genes in cultivated wheat background.



Plant Disease ◽  
2016 ◽  
Vol 100 (6) ◽  
pp. 1132-1137 ◽  
Author(s):  
Silvia B. Rosa ◽  
Brent McCallum ◽  
Anita Brûlé-Babel ◽  
Colin Hiebert ◽  
Stephen Shorter ◽  
...  

Leaf rust (Puccinia triticina) and stripe rust (P. striiformis f. tritici) affect wheat production worldwide. Brazilian ‘Toropi’ wheat has demonstrated durable leaf rust resistance in South America since its release in 1965. It was previously found to have up to two adult plant leaf rust resistance genes. The leaf and stripe rust resistance of Toropi were studied by analyzing a doubled-haploid population made by crossing with susceptible ‘Thatcher’. Toropi expressed good resistance to leaf rust in Canada, Brazil, and New Zealand. Based on field and greenhouse testing, the leaf rust resistance of Toropi is conferred by two race-nonspecific complementary adult plant genes and a race-specific adult plant gene. The stripe rust resistance of Toropi analyzed in New Zealand and in Canada is based on up to two resistance genes. Toropi should provide an important contribution to rust resistance because it expressed good leaf rust and stripe rust resistance in different parts of the world.



Agronomy ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 497 ◽  
Author(s):  
Mandeep S. Randhawa ◽  
Navtej S. Bains ◽  
Virinder S. Sohu ◽  
Parveen Chhuneja ◽  
Richard M. Trethowan ◽  
...  

Three rust diseases namely; stem rust caused by Puccinia graminis f. sp. tritici (Pgt), leaf rust caused by Puccinia triticina (Pt), and stripe rust caused by Puccinia striiformis f. sp. tritici (Pst), are the most common fungal diseases of wheat (Triticum aestivum L.) and cause significant yield losses worldwide including Australia. Recently characterized stripe rust resistance genes Yr51 and Yr57 are effective against pre- and post-2002 Pst pathotypes in Australia. Similarly, stem rust resistance genes Sr22, Sr26, and Sr50 are effective against the Pgt pathotype TTKSK (Ug99) and its derivatives in addition to commercially important Australian pathotypes. Effectiveness of these genes make them good candidates for combining with known pleiotropic adult plant resistance (PAPR) genes to achieve durable resistance against three rust pathogens. This study was planned to transfer rust resistance genes Yr51, Yr57, Sr22, Sr26, and Sr50 into two Australian (Gladius and Livingston) and two Indian (PBW550 and DBW17) wheat cultivars through marker assisted selection (MAS). These cultivars also carry other rust resistance genes: Gladius carries Lr37/Yr17/Sr38 and Sr24/Lr24; Livingston carries Lr34/Yr18/Sr57, Lr37/Yr17/Sr38, and Sr2; PBW550 and DBW17 carry Lr34/Yr18/Sr57 and Lr26/Yr9/Sr31. Donor sources of Yr51 (AUS91456), Yr57 (AUS91463), Sr22 (Sr22/3*K441), Sr26 (Sr26 WA1), and Sr50 (Dra-1/Chinese Spring ph1b/2/3* Gabo) were crossed with each of the recurrent parents to produce backcross progenies. Markers linked to Yr51 (sun104), Yr57 (gwm389 and BS00062676), Sr22 (cssu22), Sr26 (Sr26#43), and Sr50 (Sr50-5p-F3, R2) were used for their MAS and markers csLV34 (Lr34/Yr18/Sr57), VENTRIUP-LN2 (Lr37/Yr17/Sr38), Sr24#12 (Sr24/Lr24), and csSr2 (Sr2) were used to select genes present in recurrent parents. Progenies of selected individuals were grown and selected under field conditions for plant type and adult plant rust responses. Final selections were genotyped with the relevant markers. Backcross derivatives of these genes were distributed to breeding companies for use as resistance donors.



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