Adult-plant leaf rust resistance in Thatcher and Marquis wheat: a genetic analysis of the host–parasite interaction

1969 ◽  
Vol 47 (2) ◽  
pp. 267-269 ◽  
Author(s):  
P. Bartos ◽  
P. L. Dyck ◽  
D. J. Samborski

Inheritance of adult-plant resistance to race 9 of leaf rust was investigated in the wheat varieties Thatcher and Marquis. Resistance was conferred by the same recessive gene in both varieties. The genetics of virulence on adult plants of Thatcher was studied in a F2 population of cultures from a cross between races 9 and 161. A single recessive gene conferred virulence on adult plants of Thatcher. This gene was inherited independently of the genes that condition virulence on host genes Lr1, Lr2, Lr3, and Lr11.

1979 ◽  
Vol 59 (2) ◽  
pp. 329-332 ◽  
Author(s):  
P. L. DYCK ◽  
D. J. SAMBORSKI

The genetics of adult-plant resistance to leaf rust (Puccinia recondita Rob. ex. Desm.) was studied in a common wheat (Triticum aestivum L.) introduction PI 250413, originally collected in Pakistan. The resistance, although variable in expression, was conditioned bx a single recessive gene not previously identified, which was inherited independently of Lr12, Lr13 and Lr22, three previously identified genes for adult-plant leaf rust resistance. The gene present in PI 250413 was also found in five introductions from Iraq.


1959 ◽  
Vol 37 (6) ◽  
pp. 1153-1155 ◽  
Author(s):  
D. J. Samborski ◽  
W. Ostapyk

Unexpectedly heavy leaf rust development was observed on mature (ripe) field-grown plants of the resistant wheat varieties, Selkirk and Exchange. Greenhouse experiments with pure races of leaf rust showed that a partial breakdown of both seedling and adult plant resistance occurred when the plants were approaching maturity. This change in resistance would not affect yields but could result in exaggerated estimates of rust damage. Leaf rust readings in rust nurseries, at least on these varieties, should be made before the plants are ripe.


1968 ◽  
Vol 10 (2) ◽  
pp. 311-320 ◽  
Author(s):  
D. R. Knott

The inheritance of resistance to races 56 and 15B-1L was studied in back-crosses of Hope and H-44 to Marquis. The results indicated that both varieties carry the same three genes. Resistance to race 56 is controlled by two dominant genes, Sr 1 which conditions seedling or physiological resistance and Sr 2 which conditions adult plant resistance. At either the seedling or adult plant stage both genes must be present to provide full resistance to race 56. A single recessive gene, not yet named, provides resistance to race 15B-1L.The gene Sr 1 was transferred from Hope to Marquis by backcrossing and the line was crossed to the Chinese Spring monosomics. The gene proved to be on chromosome 2B (XIII).


Author(s):  
E. I. Gultyaeva ◽  
E. L. Shaydayuk

Background. Wheat leaf rust caused by Puccinia triticina Erikss. is a significant wheat disease in all regions of the Russian Federation. The genetic diversity of the cultivated wheat varieties regarding the type of resistance and genes that control it ensures reliable protection of this crop against the pathogen. The aim of this work was to characterize the diversity of new Russian varieties of winter and spring common wheat for leaf rust resistance genes (Lr-genes).Materials and Methods. The research material was represented by 43 varieties of winter and 25 of spring wheat included in the State Register of Selection Achievements of the Russian Federation in 2018-2020.Results. Using molecular markers, 18 Lr genes were identified: Lr1, Lr3, Lr9, Lr10, Lr19, Lr20, Lr21, Lr24, Lr25, Lr26, Lr28, Lr29, Lr34, Lr35, Lr37, Lr41 (39), Lr47 and Lr66. A phytopathological test was used to clarify the results of molecular analysis. Ninety-three percent of the studied wheat varieties were found to contain Lr genes, either separately or in combinations. These were the highly and partially effective genes Lr24, Lr9, and Lr19, adult plant resistance genes Lr34 and Lr37, and ineffective genes Lr1, Lr3, Lr10, Lr20, and Lr26. The Lr24 gene has been identified for the first time in Russian varieties. The spring variety ‘Leader 80’, harboring this gene, is recommended for cultivation in the West Siberian and East Siberian regions. An effective combination of Lr9 + Lr26 genes, individually overcome by the pathogen, was determined in the spring cultivar ‘Silach’, highly resistant to leaf rust. The Lr9 gene was found in the winter variety ‘Gerda’, which is recommended for cultivation in the North Caucasus region. Previously, the varieties with Lr9 were not grown in the North Caucasus. An increase in the number of leaf rust resistant accessions protected by the effective adult plant resistance gene Lr37 is noted among wheat varieties undergoing regional adaptation testing. Many of the identified Lr genes (Lr19, Lr24, Lr26, Lr34, Lr37) are linked with effective Sr genes (Sr25, Sr24, Sr31, Sr57, and Sr38), which additionally ensures stable genetic protection of wheat against stem rust.Conclusions. The obtained information about representation of Lr genes in wheat varieties should be used in regional breeding programs. A timely replacement of genetically protected varieties allows stabilizing the populational composition of the phytopathogen and reducing the likelihood of epiphytotics.


Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 90-93 ◽  
Author(s):  
A. L. Barcellos ◽  
A. P. Roelfs ◽  
M. I. B. de Moraes-Fernandes

Adult plant resistance to leaf rust in the Brazilian wheat cultivar Toropi (Triticum aestivum) was studied in crosses with the susceptible cultivar IAC 13. Cvs. Toropi and IAC 13 are susceptible at the seedling stage to race LCG-RS of Puccinia triticina Erikss., and to all other known Brazilian leaf-rust races. Thus, the resistance observed in Toropi in the field was due to adult plant-resistance genes. In the greenhouse at the adult plant stage, resistance segregated in a 7:9 ratio for two complementary recessive genes. Additionally, two recessive genes for leaf-tip necrosis were identified in the greenhouse environment. Necrosis was expressed when the two homozygous recessive genes occurred together in the F2, independently of the response to leaf rust. The resistance and leaf-necrosis genes differ from those previously reported in wheat. Segregation for leaf-rust resistance in the field at Passo Fundo, Brazil, fit a 1:3 ratio for a single recessive gene. With a different pathogen race, and in crosses of cvs. Toropi and ThatcherLr34, two recessive genes and a dominant gene for resistance were detected in the field in Mexico. The dominant gene was likely Lr34 from cv. ThatcherLr34 and the two recessive genes were likely those detected in the greenhouse adult plants tests at Passo Fundo.


Plant Disease ◽  
2021 ◽  
Author(s):  
Subhash Chander Bhardwaj ◽  
Subodh Kumar ◽  
Om Prakash Gangwar ◽  
Pramod Prasad ◽  
Prem Lal Kashyap ◽  
...  

Wheat is the second most cultivated cereal in the world and is equally important in India. Leaf (brown) rust, caused by Puccinia triticina, was most prevalent among the three rusts in all the wheat-growing areas of India, Bhutan, and Nepal during 2016 to 2019. Leaf rust samples from wheat crops in these countries were pathotyped using the wheat differential genotypes and binomial Indian system of nomenclature. To facilitate international communication, each pathotype identified was also tested on the North American differentials. A total of 33 pathotypes were identified from 1,086 samples, including 3 new pathotypes, 61R47 (162-5 = KHTDM) and 93R49 (49 = NHKTN) from India and 93R57 (20-1 = NHKTL) from Nepal. Two pathotypes, 121R60-1 (77-9/52 = MHTKL) and 121R63-1 (77-5 = THTTM), accounted for 79.46% of the population. Virulence on Lr19 was identified in 0.27% of the samples and from Nepal only. The proportion of pathotype 121R60-1 (77-9 = MHTKL) increased during these years to 57.55%. Virulence was not observed to Lr9, Lr24, Lr25, Lr28, Lr32, Lr39, Lr45, and Lr47 in the population of the Indian subcontinent. Eighteen polymorphic simple sequence repeat (SSR) primer pairs tested on the isolates amplified 48 alleles with an average of 2.66 alleles per primer pair. Based on SSR genotyping, these pathotypes could be grouped into two clades with further two subclades each. Many of the Lr genes present in Indian wheat germplasm (Lr1, Lr3a, Lr10, Lr11, Lr14a, Lr15, Lr16, Lr17, Lr20, Lr23, and Lr26) were ineffective to a majority of the pathotypes. Most of these varieties possessed a high degree of leaf rust resistance. The field resistance of wheat varieties could be attributed to the interaction of genes, unknown resistance, or adult plant resistance.


1988 ◽  
Vol 68 (3) ◽  
pp. 633-639 ◽  
Author(s):  
P. L. DYCK ◽  
O. M. LUKOW

Gene Lr29 transferred from Agropyron elongatum to chromosome 7D of wheat and gene LrVPM transferred from VPM1 both segregated as single genes for seedling resistance to leaf rust when backcrossed into common wheat (Triticum aestivum). Although the seedling resistance of the VPM lines was intermediate, their adult plant resistance was excellent. This resistance was not on chromosome 7D. The VPM lines also had seedling and adult plant resistance to stem rust. Resistant backcross lines with either Lr29 or LrVPM had higher kernel protein levels than did susceptible sister lines under both rust and rust-free conditions. Although this higher protein content was associated with weaker dough mixing properties, the remix loaf volume remained constant. Leaf rust infection had a detrimental effect on grain yield and kernel weight and on wheat quality as shown by decreased kernel protein content and farinograph absorption. Dough mixing strength was higher for the rust infected lines than the rust resistant lines.Key words: Triticum aestivum, wheat (spring), leaf rust resistance, protein content, breadmaking quality


1943 ◽  
Vol 21c (1) ◽  
pp. 10-17 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson

Nine wheat varieties were studied in two stages of growth, the seedling stage and the heading stage, for their reaction to a number of physiologic races of leaf rust of wheat, Puccinia triticina Erikss. Several varieties susceptible to certain physiologic races in the seedling stage were found to acquire, as they grew to maturity, a resistance to these races. In the adult plant, the resistance was greatest in the uppermost leaves but diminished progressively on lower leaves. The varieties tested fell into three groups on the basis of their rust reaction. (1) Renown and Regent, which developed adult plant resistance to all of the 19 races to which they were tested. In these two varieties, and possibly in other derivatives of H-44 and Hope, adult plant resistance to physiologic races of leaf rust may be a generalized phenomenon comparable to the resistance such varieties show towards stem rust. (2) Thatcher, Apex, Marquis, Reward, and Kenya R.L. 1373, which showed adult plant resistance only to certain physiologic races, a condition not hitherto encountered in other cereal rusts. (3) McMurachy and Warden × Hybrid, each of which reacted somewhat similarly in the seedling and heading stages, the former being susceptible and the latter resistant in both stages.


1971 ◽  
Vol 13 (2) ◽  
pp. 186-188 ◽  
Author(s):  
D. R. Knott

Tests were carried out to identify and locate the genes for resistance to races 15B-1L and 56 in Hope and H-44. The gene Sr1 which conditions resistance to race 56 was found to be either very closely linked or more probably allelic to Sr9. It is proposed that it be redesignated Sr9d. The gene Sr2 which conditions adult plant resistance to race 56 appears to be on chromosome 3B. The recessive gene conditioning resistance to race 15B-1L was identified as sr17 which is on chromosome 7B.


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