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

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.

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 467-469 ◽  
Author(s):  
P. L. Dyck

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.


Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 225-229 ◽  
Author(s):  
G. F. Marais

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.


Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 530-537 ◽  
Author(s):  
E. R. Kerber ◽  
P. L. Dyck

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.


Genome ◽  
1993 ◽  
Vol 36 (2) ◽  
pp. 289-293 ◽  
Author(s):  
P. L. Dyck

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.


1999 ◽  
Vol 89 (6) ◽  
pp. 518-521 ◽  
Author(s):  
E. R. Kerber ◽  
T. Aung

The common wheat cultivar Thatcher and the backcross derivative Canthatch are moderately or fully susceptible to several races of stem rust because of a suppressor on chromosome 7DL that inhibits the expression of the relevant resistance gene(s). The incorporation of leaf rust resistance gene Lr34 into ‘Thatcher’ is known to enhance stem rust resistance. The effect of this gene in a ‘Canthatch’ background and its relationship with the 7DL suppressor were determined by replacing chromosome 7D of ‘Canthatch’ with 7D of ‘Chinese Spring’, which possesses Lr34 on the short arm. ‘Canthatch’ nullisomic 7D was crossed with ‘Chinese Spring’, followed by a succession of backcrosses to the nullisomic recurrent parent. Homozygous resistant disomic and monosomic substitution lines were recovered that exhibited the same resistant reaction as that of ‘Thatcher’ possessing Lr34 and as that of ‘Canthatch’ nullisomic 7D, in which the 7DL suppressor is absent. The results indicate that, in ‘Canthatch’, Lr34 permits expression of resistance genes normally inhibited by the 7DL suppressor. Furthermore, it is likely that, in ‘Thatcher’ and ‘Thatcher’ back-cross derivatives, Lr34 inactivates the 7DL suppressor.


Genome ◽  
2008 ◽  
Vol 51 (5) ◽  
pp. 341-349 ◽  
Author(s):  
D. Ratna Anugrahwati ◽  
Kenneth W. Shepherd ◽  
Dawn C. Verlin ◽  
Peng Zhang ◽  
Ghader Mirzaghaderi ◽  
...  

1969 ◽  
Vol 11 (2) ◽  
pp. 266-274 ◽  
Author(s):  
K. N. Kao ◽  
D. R. Knott

The inheritance of pathogenicity in wheat stem rust was studied in selfed cultures of races 29 and 111, F1 and F2 cultures of a cross between the two races and cultures from a backcross to race 29. The various cultures were tested on Marquis and Prelude and on a series of lines of these varieties carrying single genes for stem rust resistance. Virulence on Sr 5, Sr 6, Sr 8, Sr 9a, Sr 14 and a gene in Marquis was recessive and in each case there was a single gene for virulence corresponding to each gene for resistance. Virulence on Sr 1 was possibly controlled by two dominant complementary genes. There appeared to be two alleles for virulence on Prelude, one dominant and one recessive.


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