Gamma irradiation induced deletions in an alien chromosome segment of the wheat 'Indis' and their use in gene mapping

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 225-229 ◽  
Author(s):  
G. F. Marais
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Rust Resistance ◽  
D1 Protein ◽  
Leaf Rust Resistance ◽  
Chromosome Segment ◽  
Translocation Line ◽  
Deletion Mapping ◽  
Stem Rust Resistance Gene ◽  
Interspecific Gene Transfer

Deletion mutants were produced in a translocated chromosome segment derived from Thinopyrum distichum (Thunb.) Löve. Spikes of the translocation line 'Indis' were irradiated with gamma rays at dosages of 15, 20, and 25 Gy. The irradiated spikes were pollinated with 'Inia 66' pollen and the F2 and F3 generations screened for translocation mutants, using the genes for leaf rust resistance and yellow endosperm pigmentation as markers. Finally, endopeptidase polymorphisms were utilized to select mutant translocation homozygotes within each of 29 families. An investigation of polymorphisms at the α-Amy-D2 and Wsp-D1 loci of chromosome arm 7DL revealed that 'Indis' did not produce an α-AMY-D2 product, but it did produce a novel WSP-D1 protein. The mutants were characterized for their leaf and stem rust resistances and the presence of WSP-D1 and yellow flour pigments. The stem rust resistance gene could not be accurately mapped. The linear order of the remaining loci on 7DL was centromere - leaf rust resistance - Wsp-D1 and yellow pigment. The data obtained suggested that the 'Indis' translocation has homo(eo)logy to the Lr19 translocation and homoeology to 7DL of common wheat.Key words: wheat, interspecific gene transfer, translocation, deletion mapping.

Linkage and expression of genes for resistance to leaf rust and stem rust in triticale

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 115-118 ◽  
Author(s):  
S. J. Singh ◽  
R. A. McIntosh
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Genetic Linkage ◽  
Rust Resistance ◽  
Single Gene ◽  
Leaf Rust Resistance ◽  
Stem Rust Resistance ◽  
Stem Rust Resistance Gene ◽  
Expression Of Genes ◽  
Triticosecale Wittmack

Leaf rust resistance in five triticale cultivars was controlled by a single gene designated LrSatu. This gene was closely linked in coupling with the stem rust resistance gene SrSatu believed to be located on chromosome 3R. Approximately 50% of lines in the 17th International Triticale Screening Nursery possessed SrSatu and LrSatu. Lines carrying SrSatu and LrSatu occurred more frequently among complete than in substituted triticale lines.Key words: × Triticosecale Wittmack, P. graminis f.sp. tritici, P. recondita f.sp. tritici, leaf rust, stem rust, rust resistnace, genetic linkage.

A physical map of the Thinopyrum-derived Lr19 translocation

Genome ◽  
1996 ◽  
Vol 39 (5) ◽  
pp. 1013-1019 ◽  
Author(s):  
R. Prins ◽  
G. F. Marais ◽  
A. S. Marais ◽  
B. J. H. Janse ◽  
Z. A. Pretorius
Keyword(s):  
Key Words ◽  
Leaf Rust ◽  
Rust Resistance ◽  
Physical Map ◽  
Leaf Rust Resistance ◽  
Chromosome Segment ◽  
Deletion Mapping ◽  
Chromosome Arm ◽  
Marker Loci

Twenty-nine lines with deletions in the Lr19 ('Indis') translocated chromosome segment were used to physically map three Thinopyrum RFLP loci as well as the Sr25 and Sd1 loci. From the data, the relative locations of marker loci on the translocation were determined as: Sd1, Xpsr165, Xpsr105, Xps129, Lr19, Wsp-D1, Sr25/Y. The data confirmed the reported homoeology between the Lr19 segment and chromosome arm 7DL of wheat. Also, it seems that the Lr19 translocation in 'Indis' is very similar to the Lr19 segment in the T4 source and that the former may not derive from Thinopyrum distichum. Key words : deletion mapping, leaf rust resistance.

The association of a gene for leaf rust resistance with the chromosome 7D suppressor of stem rust resistance in common wheat

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 467-469 ◽  
Author(s):  
P. L. Dyck
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Stem Rust ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Suppressor Gene ◽  
Stem Rust Resistance ◽  
Recurrent Parent ◽  
Cytogenetic Evidence

Backcross lines of gene LrT2 for resistance to leaf rust in the common wheat (Triticum aestivum L.) 'Thatcher' unexpectedly show improved resistance to stem rust compared with that of the recurrent parent. Genetic–cytogenetic evidence indicates that LrT2 is on chromosome 7D, which is known to carry the "suppressor" gene(s) that prevent the expression of stem rust resistance conferred by other genes in 'Canthatch'. Thus, LrT2 may be a nonsuppressing allele of the suppressor gene(s) or be closely linked to such an allele. LrT2 has been designated Lr34. Key words: Triticum, wheat, rust resistance.

Identification of stem rust and leaf rust resistance genes in Amagalon oats

2001 ◽  
Vol 52 (10) ◽  
pp. 1011 ◽  
Author(s):  
K. N. Adhikari ◽  
R. A. McIntosh
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Rust Resistance ◽  
Recessive Gene ◽  
Leaf Rust Resistance ◽  
Leaf Rust Resistance Gene ◽  
Breeding Programs ◽  
Sensitivity Tests ◽  
Unique Source ◽  
Leaf Rust Resistance Genes

Studies were undertaken to identify the genes conferring stem rust and leaf rust resistances in Amagalon and to determine the usefulness of this line as a source of rust resistance in oat breeding programs. Amagalon was crossed with certain rust-resistant and rust-susceptible lines and segregating populations were tested with pathotypes of Puccinia graminis avenae and P. coronata avenae. Tests with the widely virulent P. graminis avenae pt 94+Pg-13 indicated that resistance in Amagalon was governed by the complementary recessive gene complex known as Pg-a. This hypothesis was further substantiated by temperature sensitivity tests and by a test of induced susceptibility to stem rust, known to be unique to lines possessing Pg-a. However, Amagalon yielded a unique source of resistance to leaf rust that was effective against current pathotypes of P. coronata avenae in Australia. This gene, assumed to be Pc91, was inherited independently of a second leaf rust resistance gene present in cv. Culgoa. It was concluded that Amagalon is a useful source of resistance to leaf rust that should be used in combination with other genes for resistance to prolong its effectiveness.

Transfer to hexaploid wheat of linked genes for adult-plant leaf rust and seedling stem rust resistance from an amphiploid of Aegilops speltoides × Triticum monococcum

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 530-537 ◽  
Author(s):  
E. R. Kerber ◽  
P. L. Dyck
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Dominant Gene ◽  
Leaf Rust Resistance ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Aegilops Speltoides ◽  
Plant Leaf

A partially dominant gene for adult-plant leaf rust resistance together with a linked, partially dominant gene for stem rust resistance were transferred to the hexaploid wheat cultivar 'Marquis' from an amphiploid of Aegilops speltoides × Triticum monococcum by direct crossing and backcrossing. Pathological evidence indicated that the alien resistance genes were derived from Ae. speltoides. Differential transmission of the resistance genes through the male gametes occurred in hexaploid hybrids involving the resistant 'Marquis' stock and resulted in distorted segregation ratios. In heterozygotes, pairing between the chromosome arm with the alien segment and the corresponding arm of the normal wheat chromosome was greatly reduced. The apparent close linkage between the two resistance genes, 3 ± 1.07 crossover units, was misleading because of this decrease in pairing in the presence of the 5B diploidizing mechanism. The newly identified gene for adult-plant leaf rust resistance, located on chromosome 2B, is different from adult-plant resistance genes Lr12, Lr13, and Lr22 and from that in the hexaploid accession PI250413; it has been designated Lr35. It is not known whether the newly transferred gene for stem rust resistance differs from Sr32, also derived from Ae. speltoides and located on chromosomes 2B.Key words: hexaploid, Triticum, Aegilops, aneuploid, Puccinia graminis, Puccinia recondita.

Resistance to wheat leaf rust and stem rust in Triticum tauschii and inheritance in hexaploid wheat of resistance transferred from T. tauschii

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 813-822 ◽  
Author(s):  
R. L. Innes ◽  
E. R. Kerber
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Triticum Tauschii ◽  
Synthetic Hexaploids ◽  
Seedling Leaf ◽  
Leaf Rust Resistance Genes

Twelve accessions of Triticum tauschii (Coss.) Schmal. were genetically analyzed for resistance to leaf rust (Puccinia recondita Rob. ex Desm.) and stem rust (Puccinia graminis Pers. f.sp. tritici Eriks. and E. Henn.) of common wheat (Triticum aestivum L.). Four genes conferring seedling resistance to leaf rust, one gene conferring seedling resistance to stem rust, and one gene conferring adult-plant resistance to stem rust were identified. These genes were genetically distinct from genes previously transferred to common wheat from T. tauschii and conferred resistance to a broad spectrum of pathogen races. Two of the four seedling leaf rust resistance genes were not expressed in synthetic hexaploids, produced by combining tetraploid wheat with the resistant T. tauschii accessions, probably owing to the action of one or more intergenomic suppressor loci on the A or B genome. The other two seedling leaf rust resistance genes were expressed at the hexaploid level as effectively as in the source diploids. One gene was mapped to the short arm of chromosome 2D more than 50 cM from the centromere and the other was mapped to chromosome 5D. Suppression of seedling resistance to leaf rust in synthetic hexaploids derived from three accessions of T. tauschii allowed the detection of three different genes conferring adult-plant resistance to a broad spectrum of leaf rust races. The gene for seedling resistance to stem rust was mapped to chromosome ID. The degree of expression of this gene at the hexaploid level was dependent on the genetic background in which it occurred and on environmental conditions. The expression of the adult-plant gene for resistance to stem rust was slightly diminished in hexaploids. The production of synthetic hexaploids was determined to be the most efficient and flexible method for transferring genes from T. tauschii to T. aestivum, but crossing success was determined by the genotypes of both parents. Although more laborious, the direct introgression method of crossing hexaploid wheat with T. tauschii has the advantages of enabling selection for maximum expression of resistance in the background hexaploid genotype and gene transfer into an agronomically superior cultivar.Key words: Triticum tauschii, rust resistance, gene expression, gene transfer, wheat, synthetic hexaploid.

scholarly journals The recognition of an alien chromosome segment translocated to a wheat chromosome

1967 ◽  
Vol 10 (3) ◽  
pp. 295-301 ◽  
Author(s):  
G. Kimber
Keyword(s):  
Leaf Rust ◽  
Rust Resistance ◽  
Wheat Variety ◽  
Wheat Chromosome ◽  
Leaf Rust Resistance ◽  
Chromosome Segment ◽  
Interference Microscopy ◽  
Alien Chromosome ◽  
Small Segment

1. Chromosome 6B of T. aestivum, to which a small segment of an Ae. umbellulata chromosome had been translocated, was examined both by interference microscopy and in stained preparations.2. In the stained preparation a constriction was observed in the long arm of chromosome 6B and also a terminal knob that was also observed on chromosome A of Ae. umbellulata.3. These features were also observed by interference microscopy and in addition the portion of the chromosome 6B of Transfer distal to the constriction had different phase-retarding properties.4. It is concluded that the part of chromosome 6B distal to the constriction is the part of Ae. umbellulata chromosome A which carries the gene for the leaf-rust resistance of that species and of the wheat variety into which it was translocated.

Inheritance of leaf rust and stem rust resistance in 'Roblin' wheat

Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 289-293 ◽  
Author(s):  
P. L. Dyck
Keyword(s):  
Triticum Aestivum ◽  
Leaf Rust ◽  
Stem Rust ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Susceptible Cultivar ◽  
Wheat Leaf

The Canadian common wheat (Triticum aestivum L.) cultivar 'Roblin' is resistant to both leaf rust (Puccinia recondita Rob. ex. Desm.) and stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.). To study the genetics of this resistance, 'Roblin' was crossed with 'Thatcher', a leaf rust susceptible cultivar, and RL6071, a stem rust susceptible line. A set of F6 random lines was developed from each cross. The random lines and the parents were grown in a field rust nursery artificially inoculated with a mixture of P. recondita and P. graminis isolates and scored for rust reaction. The same material was tested with specific races of leaf rust and stem rust. These data indicated that 'Roblin' has Lr1, Lr10, Lr13, and Lr34 for resistance to P. recondita and Sr5, Sr9b, Sr11, and possibly Sr7a and Sr12 for resistance to P. graminis. In a 'Thatcher' background, the presence of Lr34 contributes to improve stem rust resistance, which appears also to occur in 'Roblin'.Key words: Triticum aestivum, wheat, leaf rust resistance, stem rust resistance.

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