scholarly journals Wheat Resistance to Stripe and Leaf Rusts Conferred by Introgression of Slow Rusting Resistance Genes

2021 ◽  
Vol 7 (8) ◽  
pp. 622
Author(s):  
Reda Ibrahim Omara ◽  
Atef Abdelfattah Shahin ◽  
Shaimaa Mahmoud Ahmed ◽  
Yasser Sabry Mostafa ◽  
Saad Abdulrahman Alamri ◽  
...  

Twenty-three wheat genotypes were evaluated for stripe and leaf rusts, caused by Puccinia striiformis f. sp. tritici and Puccinia triticina f. sp. tritici, respectively, at seedling and adult stages under greenhouses and field conditions during the 2019/2020 and 2020/2021 growing seasons. The race analysis revealed that 250E254 and TTTST races for stripe and leaf rusts, respectively were the most aggressive. Eight wheat genotypes (Misr-3, Misr-4, Giza-171, Gemmeiza-12, Lr34/Yr18, Lr37/Yr17, Lr46/Yr29, and Lr67/Yr46) were resistant to stripe and leaf rusts at seedling and adult stages. This result was confirmed by identifying the resistance genes: Lr34/Yr18, Lr37/Yr17, Lr46/Yr29, and Lr67/Yr46 in these genotypes showing their role in the resistance. Sids-14 and Shandweel-1 genotypes were susceptible to stripe and leaf rusts. Twelve crosses between the two new susceptible wheat genotypes and the three slow rusting genes (Lr34/Yr18, Lr37/Yr17, and Lr67/Yr46) were conducted. The frequency distribution of disease severity (%) in F2 plants of the twelve crosses was ranged from 0 to 80%. Resistant F2 plants were selected and the resistance genes were detected. This study is important for introducing new active resistance genes into the breeding programs and preserving diversity among recently released wheat genotypes.

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 455-464 ◽  
Author(s):  
Lin Zhang ◽  
Congcong Shi ◽  
Lingrui Li ◽  
Min Li ◽  
Qingfang Meng ◽  
...  

Wheat leaf rust, caused by Puccinia triticina, is an important fungal disease of wheat in China. To study races of the pathogen in China, leaf rust samples were collected from 14 provinces in 2014 and 15 provinces in 2015. From the samples, 494 single-uredinial isolates were derived from the 2014 collection and 649 from the 2015 collection. These isolates were tested on 40 near-isogenic lines of Thatcher carrying single leaf rust resistance genes. From the isolates, 84 races were identified in 2014 and 65 races in 2015. Races THTT (22.1%), THTS (19.6%), THJT (8.7%), PHTT (4.9%), and PHJT (3.6%) were the most common races in 2014, and THTT (28.4%), THTS (12.8%), THJT (11.6%), THJS (9.9%), and PHTT (9.7%) were the most frequent in 2015. All of these races were avirulent to resistance genes Lr9 and Lr24. THTT and THTS, the most frequent races in both years, were widely distributed throughout the country. The frequencies of isolates with virulence to Lr1, Lr2a, Lr2c, Lr3, Lr16, Lr26, Lr11, Lr17, LrB, Lr10, Lr14a, Lr2b, Lr3bg, Lr14b, Lr32, Lr33, and Lr50 were over 80%, whereas the frequencies of virulence to Lr9, Lr19, Lr25, Lr28, Lr29, and Lr47 were less than 3.5%. In the present study, all isolates were avirulent to Lr24 and Lr38. The race analysis and individual virulence frequencies provide guidance to breeders in choosing leaf rust resistance genes for use in breeding programs.


Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 499-504 ◽  
Author(s):  
A. H. Yahyaoui ◽  
M. S. Hakim ◽  
M. El Naimi ◽  
N. Rbeiz

Virulence-avirulence phenotypes of Puccinia striiformis isolates collected in Lebanon and Syria were determined on seedlings of the wheat-yellow rust differential genotypes. We found 25 and 11 physiologic races over 6 years (1994 to 1999) in Syria and Lebanon, respectively. The composition of physiologic races found in Syria and Lebanon differed greatly between 1994 and 1999. Races identified in 1999, such as 230E150 and 230E134, have wider spectra of virulence on resistant genotypes than races collected in 1994. In Lebanon, three races were found in 1994 compared with six races in 1999. Yellow rust differential genotypes were used in a trap nursery to monitor yellow rust populations under natural conditions. Races identified from cultivars in the trap nursery in Syria and Lebanon, and from land race cultivars in Iraq, were recovered among the races identified from farm fields. Yellow rust samples were collected from Yemen, and none of the races identified from Yemen samples were identical to those in Syria and Lebanon. Virulence frequencies in the yellow rust population on the differential genotypes tested in the trap nurseries were above 70% for some resistance genes. Yellow rust populations in Syria and Lebanon have diverse virulence phenotypes. P. striiformis populations appear to be changing over, and this would be an important consideration for wheat breeding programs in the region.


2013 ◽  
Vol 53 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Safar Ali Safavi ◽  
Assadollah Babai Ahari ◽  
Farzad Afshari ◽  
Mahdi Arzanlou

Abstract Race-specific resistance of barley (Hordeum vulgare L.) to the yellow rust caused by Puccinia striiformis f. sp. hordei, has been reported to be short-lived. Slow rusting resistance has been reported to last for a long time. Twenty Iranian barley cultivars along with resistant and susceptible controls were tested during the 2009-2010 and the 2010-2011 cropping seasons, in field plots at the Ardabil Agricultural Research Station (Iran). The cultivars were tested to identify slow rusting genotypes through epidemiological variables which included: final rust severity (FRS), apparent infection rate (r), relative area under the disease progress curve (rAUDPC), and coefficient of infection (CI). Moreover, differential sets were evaluated in order to determine effective and ineffective resistance genes to barley yellow rust. Results of the mean comparison of resistance parameters showed that cultivars Makouee, Dasht, Fasih, and Arass had low values of FRS, CI, r and rAUDPC compared with susceptible cultivars. The cultivars Walfajre, Abidar and Sahand which had moderate values of the different parameters, were marked as possessing a moderate level of slow rusting. The rest of the cultivars which had high values of different quantitative parameters, were grouped as having a low level of slow rusting or as susceptible. The correlation coefficient between different parameters of slow rusting was significantly high (r = 0.83-0.98). The virulence profile of the prevalent races revealed that rpsEm1, rpsEm2, rpsHF, Rps4, rpsVa1, rpsVa2, rpsAst were effective, and rps2, Rps1.b were ineffective resistance genes during the two year testing period.


Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1111-1118 ◽  
Author(s):  
J. X. Zhang ◽  
R. P. Singh ◽  
J. A. Kolmer ◽  
J. Huerta-Espino ◽  
Y. Jin ◽  
...  

The CIMMYT-developed spring wheat ‘Brambling’ has a high level of adult-plant resistance (APR) to leaf rust caused by Puccinia triticina. Our objectives were to determine the genetic basis of resistance in seedlings and adult plants and the magnitude of genotype × environment effects on the expression of APR. Brambling was crossed with spring wheat ‘Jupateco 73S’ that is highly susceptible to current predominant P. triticina races in Mexico and the United States. The F1, F2:3, F4:5, F4:6, and F5:7 recombinant inbred lines (RILs) were evaluated under artificial field epidemics in Mexico and St. Paul, MN. The RILs also were tested with five races of P. triticina in greenhouse seedling experiments. A DNA marker was used to postulate the presence of slow-rusting gene Lr34 in the RILs. F1 data suggested strong dominant effect of the APR genes in Brambling. The proportion of homozygous susceptible lines in each generation indicated the presence of three effective resistance genes in adult plants of Brambling in tests in Mexico and three or four genes in tests in St. Paul. The RILs segregated for seedling genes Lr14a and Lr23 and adult-plant slow-rusting gene Lr34 derived from Brambling and Lr17a from Jupateco 73S. Gene Lr23 conditioned APR to P. triticina races present in the St. Paul nursery and accounted for the additional effective gene at this location. Expression of APR was influenced by the environment in the RILs, even though Brambling displayed a consistent response, indicating that stability of APR can be achieved by combinations of slow-rusting resistance genes.


Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Z. F. Li ◽  
X. C. Xia ◽  
Z. H. He ◽  
X. Li ◽  
L. J. Zhang ◽  
...  

Identification of resistance genes is important for developing leaf rust resistant wheat (Triticum aestivum) cultivars. A total of 102 Chinese winter wheat cultivars and advanced lines were inoculated with 24 pathotypes of Puccinia triticina for postulation of leaf rust resistance genes effective at the seedling stage. These genotypes were also planted in the field for characterization of slow rusting responses to leaf rust in the 2006–07 and 2007–08 cropping seasons. Fourteen leaf rust resistance genes—Lr1, Lr2a, Lr3bg, Lr3ka, Lr14a, Lr16, Lr17a, Lr18, Lr20, Lr23, Lr24, Lr26, Lr34, and LrZH84—either singly or in combinations, were postulated in 65 genotypes, whereas known resistance genes were not identified in the other 37 accessions. Resistance gene Lr26 was present in 44 accessions. Genes Lr14a and Lr34 were each detected in seven entries. Lr1 and Lr3ka were each found in six cultivars, and five lines possessed Lr16. Lr17a and Lr18 were each identified in four lines. Three cultivars were postulated to possess Lr3bg. Genes Lr20, Lr24, and LrZH84 were each present in two cultivars. Each of the genes Lr2a and Lr23 may exist in one line. Fourteen genotypes showed slow leaf rusting resistance in two cropping seasons.


Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1302-1312 ◽  
Author(s):  
Z. F. Li ◽  
X. C. Xia ◽  
X. C. Zhou ◽  
Y. C. Niu ◽  
Z. H. He ◽  
...  

Identification of seedling and slow stripe rust resistance genes is important for gene pyramiding, gene deployment, and developing slow-rusting wheat cultivars to control the disease. A total of 98 Chinese lines were inoculated with 26 pathotypes of Puccinia striiformis f. sp. tritici for postulation of stripe rust resistance genes effective at the seedling stage. A total of 135 wheat lines were planted at two locations to characterize their slow rusting responses to stripe rust in the 2003-2004 and 2004-2005 cropping seasons. Genes Yr2, Yr3a, Yr4a, Yr6, Yr7, Yr9, Yr26, Yr27, and YrSD, either singly or in combinations, were postulated in 72 lines, whereas known resistance genes were not identified in the other 26 accessions. The resistance genes Yr9 and Yr26 were found in 42 and 19 accessions, respectively. Yr3a and Yr4a were detected in two lines, and four lines may contain Yr6. Three lines were postulated to possess YrSD, one carried Yr27, and one may possess Yr7. Thirty-three lines showed slow stripe rusting resistance at two locations in both seasons.


Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 728-736 ◽  
Author(s):  
B. R. Basnet ◽  
R. P. Singh ◽  
S. A. Herrera-Foessel ◽  
A. M. H. Ibrahim ◽  
J. Huerta-Espino ◽  
...  

Identifying and utilizing rust resistance genes in wheat has been hampered by the continuous and rapid emergence of new pathogen races. A major focus of many wheat breeding programs is achieving durable adult plant resistance (APR) to yellow (stripe) rust (YR) and leaf (brown) rust (LR), caused by Puccinia striiformis and P. triticina, respectively. This study aimed to determine the genetic basis of resistance to YR and LR in the common spring wheat ‘Quaiu 3’. To that end, we evaluated 198 F5 recombinant inbred lines (RILs), derived from a cross of susceptible ‘Avocet-YrA’ with Quaiu 3, for APR to LR and YR in artificially inoculated field trials conducted in Mexico during the 2009 and 2010 growing seasons. High narrow-sense heritability (h2) estimates, ranging between 0.91 and 0.95, were obtained for both LR and YR disease severities for both years. The quantitative and qualitative approaches used to estimate gene numbers showed that, in addition to known resistance genes, there are at least two to three APR genes associated with LR and YR resistance in the RIL population. The moderately effective race-specific resistance gene Lr42 and the pleiotropic slow-rusting APR gene Lr46/Yr29 were found to interact with additional unidentified APR genes. The unidentified APR genes should be of particular interest for further characterization through molecular mapping, and for utilization by wheat breeding programs.


2020 ◽  
Author(s):  
Ali Saremirad ◽  
Mohammad Bihamta ◽  
Ali Malihipour ◽  
Khodadad Mostafavi ◽  
Hadi Alipour

Abstract Background Stem rust caused by Puccinia graminis f. sp. tritici (Pgt) is an important disease of wheat in the world. Pgt pathogen is constantly evolving and creating more virulent races that break down stem rust (Sr) resistance genes. As a result, many of Sr genes have become ineffective against new Pgt races. Exploring new sources of resistance to detect new Sr genes/QTLs is very important in order to introducing them into wheat breeding programs and developing resistant wheat cultivars. The objective of the present study was to evaluate 297 Iranian wheat genotypes for resistance to stem rust at seedling stage and to detect Sr resistance genes/QTLs through association mapping (AM). Results A set of 297 Iran bread wheat cultivars and landraces were evaluated for infection type and latent period in four race of Pgt. Genotypic data of 282 genotypes were available, so AM was performed based on 282 genotypes. The results of population structure analysis showed that 277 genotypes clearly were distinguished in the three subpopulations and the other five genotypes were classified in the mixed group. The mean linkage disequilibrium decreased with increasing genetic distance. The markers did not have a uniform distribution on the genomes, so the share of each of the A, B and D genomes in commercial cultivars and landraces was approximately 37, 46 and 17%, respectively. Collectively, 69 QTLs for infection type and 62 QTLs for latent period of studied Pgt races were identified in the original dataset (P ≤ 0.001). In the imputed SNPs dataset, the number of QTLs for infection type increased to 504 QTL and for latent period increased to 454 QTLs (P ≤ 0.001). Conclusion Based on the results of this study, it can be concluded that the Iranian wheat genotypes are valuable source resistance to stem rust. By incorporating these genotypes into wheat breeding programs and optimizing effective resistance genes, an important step can be taken to prevent the threat of and the disease to ensure food security. This study provides additional useful information for selection of resistant genotypes against the disease by improving marker-assisted selection efficiency.


2020 ◽  
pp. 1-4
Author(s):  
Maysoun Mohamad Saleh ◽  
Fariza Alsarhan Alsarhan

Study was conducted at Al-Raqqa Research Centre in The General Commission for Scientific Agricultural Research in Syria during the growing seasons 2011/2012. Eight primitive wheat genotypes and two local cultivated varieties were planted in Randomized Complete Block Design in three replications, yield components (number of fertile tillers, number and weight of grains per spike and weight of thousand grain) were studied. Results showed that the genotype Persian 64 was significantly superior in three traits of yield components (number of fertile tillers, number and weight of grains per spike) comparing to the check sham5, and also the genotype Polish 194 was significantly superior in weight of thousand grain comparing to both checks sham3 and sham5 (53.12, 40.80, 40.02) g respectively with an increase rate 30.20% and 32.73% comparing to both checks sham3 and sham5 respectively. It is recommended to use the superior genotypes in breeding programs to ensure the sustainability of wheat production.


2020 ◽  
Vol 9 (1) ◽  
pp. 51-70
Author(s):  
Walid M. El-Orabey ◽  
Mamdouh A. Ashmawy ◽  
Atef A. Shahin ◽  
Mohamed I. Ahmed

Yellow (stripe) rust caused by Puccinia striiformis f. sp. tritici, is a serious problem of wheat (Triticum aestivum) production in many parts of the world including Egypt. The pathogen is capable to produce new physiological races that attack resistant varieties and develop epidemic under optimal environmental conditions which results in a serious yield loss. Host resistance is the most economical way to manage wheat stripe rust. Therefore, the present study was conducted to evaluate the reaction of 53 wheat genotypes, delivered to Egypt by International Maize and Wheat Improvement Center (CIMMYT) by artificial inoculation against the major virulent races at adult plant stage at two locations; Itay El-Baroud and Sakha Agricultural Research Stations; during three growing seasons i.e. 2016/17, 2017/18 and 2018/19. Results of the current study showed that 34 wheat genotypes; No. 2, 3, 4, 5, 6, 8, 10, 11, 12, 13, 14, 15, 16, 17, 21, 22, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 40, 41, 42, 44, 45 and 48 were resistant and had the lowest values of FRS, ACI, and AUDPC. Therefore, we can select these genotypes as resistant lines in the breeding program for resistance to yellow rust. As for 1000 kernel weight, 10 wheat genotypes i.e. 4, 6, 11, 14, 17, 28, 33, 34, 41 and 48 showed the highest values of 1000 kernel weight and were also resistant to yellow rust. Correlation analysis of different parameters also showed a high correlation between FRS, ACI, RRI and AUDPC with 1000 kernel weight of the tested wheat genotypes. Intensive genetic and molecular studies are useful for developing high yielding and disease resistant wheat cultivars in Egypt.


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