The transfer of leaf and stem rust resistance from wild emmer wheats to durum and common wheat

2005 ◽  
Vol 85 (1) ◽  
pp. 49-57 ◽  
Author(s):  
D. R. Knott ◽  
Dapeng Bai ◽  
Janice Zale

Wild emmer wheats (Triticum turgidum var. dicoccoides L.) are potentially valuable sources of leaf rust (Puccinia triticina Eriks.) and stem rust (Puccinia graminis f. sp. tritici Eriks. & Henn.) resistance in breeding both durum (T. turgidum var. durum L.) and common wheat (T. aestivum L.). In an extension of previous work, 11 rust resistant accessions of wild emmer wheat were crossed and backcrossed from two to five times to susceptible durum or common wheats. Genes for leaf or stem rust resistance were transferred singly into several susceptible genotypes. Backcross lines homozygous for resistance to leaf rust were tested with a set of either 9 or 10 leaf rust races and those homozygous for resistance to stem rust were tested with a set of either 10 or 13 stem rust races. The emmer wheats proved to carry a number of genes for resistance to each rust. In most cases, when a cross was made to a hexaploid wheat, resistance to both rusts was suppressed in the F1 seedlings, even when resistance was dominant in the tetraploids. Nevertheless, resistance was successfully transferred from several accessions to the hexaploids, indicating that suppressors on the A or B genome chromosomes were involved and segregation occurred for them. Rust resistance tended to decrease when it was transferred to another species, particularly hexaploid wheat. A number of lines carrying genes for either leaf rust or stem rust resistance were resistant to all races with which they were tested and have potential in wheat breeding. Key words: Emmer wheat, Triticum turgidum var. dicoccoides, stem rust, leaf rust, suppressors

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.


1977 ◽  
Vol 28 (1) ◽  
pp. 37 ◽  
Author(s):  
RA McIntosh ◽  
PL Dyck ◽  
GJ Green

The wheat cultivars Agent and Agatha each possess closely linked genes for resistance to Puccinia graminis tritici and P. recondita derived from Agropyron elongatum. The genes in Agent, located in chromosome 3D, were designated Sr24 and Lr24. The gene in Agatha for resistance to P. graminis tritici was designated Sr25 and is linked with Lr19 in chromosome 7D. Both Agent and Agatha possess additional genes for resistance to certain cultures of P. graminis tritici. Sr24 is considered a valuable source of resistance for wheat-breeding purposes, but Sr25 conferred an inadequate level of resistance to adult plants. A translocation from an A. elongatum chromosome to wheat chromosome 6A, present in Australian cultivars Eagle, Kite and Jabiru, carries a third gene, Sr26, for stem rust resistance.


1996 ◽  
Vol 76 (2) ◽  
pp. 317-319 ◽  
Author(s):  
D. R. Knott

Two genes for stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) resistance were transferred from the Ethiopian durum wheat (Triticum turgidum L) accession St. 464 to Thatcher and Prelude/8* Marquis common wheat. One gene was shown by monosomic analysis to be on chromosome 4B and proved to be Sr7a. Monosomic analysis failed to locate the second gene. It is only partially dominant and conditions resistance to a range of races. Key words: Rust resistance, stem rust, wheat, Puccinia graminis tritici, Triticum aestivum, Triticum turgidum


Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 405-409 ◽  
Author(s):  
Dapeng Bai ◽  
D. R. Knott

Six accessions of Triticum turgidum var. dicoccoides L. (4x, AABB) of diverse origin were tested with 10 races of leaf rust (Puccinia recondita f.sp. tritici Rob. ex Desm.) and 10 races of stem rust (P. graminis f.sp. tritici Eriks. &Henn.). Their infection type patterns were all different from those of lines carrying the Lr or Sr genes on the A or B genome chromosomes with the same races. The unique reaction patterns are probably controlled by genes for leaf rust or stem rust resistance that have not been previously identified. The six dicoccoides accessions were crossed with leaf rust susceptible RL6089 durum wheat and stem rust susceptible 'Kubanka' durum wheat to determine the inheritance of resistance. They were also crossed in diallel to see whether they carried common genes. Seedlings of F1, F2, and BC1F2 generations from the crosses of the dicoccoides accessions with RL6089 were tested with leaf rust race 15 and those from the crosses with 'Kubanka' were tested with stem rust race 15B-1. The F2 populations from the diallel crosses were tested with both races. The data from the crosses with the susceptible durum wheats showed that resistance to leaf rust race 15 and stem rust race 15B-1 in each of the six dicoccoides accessions is conferred by a single dominant or partially dominant gene. In the diallel crosses, the dominance of resistance appeared to be affected by different genetic backgrounds. With one exception, the accessions carry different resistance genes: CI7181 and PI 197483 carry a common gene for resistance to leaf rust race 15. Thus, wild emmer wheat has considerable genetic diversity for rust resistance and is a promising source of new rust resistance genes for cultivated wheats.Key words: wheat rust, leaf rust, stem rust, rust resistance, genetic diversity.


Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 788-792 ◽  
Author(s):  
P. L. Dyck

A partially dominant gene for seedling resistance to Puccinia graminis f.sp. tritici was transferred from two accessions of Triticum araraticum (PGR 6126 and PGR 6195) to hexaploid wheat by a series of backcrosses. This gene confers an intermediate level (infection type 1+ to 2) of resistance to a large number of P. graminis isolates. Because of linkage with the genes Lr13 (1.0%), Lr23 (4.7%), Lr16 (34.4%), Sr36 (21.9%) and the Sr9 (28.0%) locus, this gene is probably on the short arm of chromosome 2B. It has been assigned the symbol Sr40. No apparent deleterious quality characteristics were associated with the transfer of Sr40. This gene is being combined with the closely linked gene Lr13. This recombinant line should be useful in wheat breeding. The concurrent attempt to transfer resistance to P. recondita from T. araraticum to hexaploid wheat was not successful.Key words: Triticum aestivum, stem rust resistance, Triticum araraticum.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 277
Author(s):  
Fernando Martínez-Moreno ◽  
Patricia Giraldo ◽  
María del Mar Cátedra ◽  
Magdalena Ruiz

Spain has a great landrace diversity of the subspecies of the tetraploid species Triticum turgidum L., namely, durum (or durum wheat), turgidum (or rivet wheat) and dicoccon (or domesticated emmer wheat). These wheats have to confront several foliar diseases such as the leaf rust. In this work, a core collection of 94 landraces of tetraploid wheats were inoculated with three leaf rust isolates. Besides, a larger collection (of 192 accessions) was evaluated in the field. Although the majority of landraces were susceptible, approximately 20% were resistant, especially domesticated emmer wheat landraces. Several variables, such as late heading and red coat seeds were associated to resistant accessions. Regarding ecogeographic variables, a higher rainfall from October to February and more uniform temperature were found in the area of origin of resistant landraces. Based on these results, several resistant landraces were identified that potentially may be used in durum wheat breeding programs. In addition, a predictive model was elaborated to develop smaller subsets for future screening with a higher hit rate for rust resistance.


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.


Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 941-944 ◽  
Author(s):  
M. N. Rouse ◽  
Y. Jin

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, has been effectively controlled through the use of genetic resistance. P. graminis f. sp. tritici race TTKSK (Ug99) possesses virulence to many resistance genes that have been used in wheat breeding worldwide. One strategy to aid breeders in developing resistant cultivars is to utilize resistance genes transferred from wild relatives to wheat. Stem rust resistance genes have previously been introgressed from Triticum monococcum to wheat. In order to identify additional resistance genes, we screened 1,061 accessions of T. monococcum and 205 accessions of T. urartu against race TTKSK and four additional P. graminis f. sp. tritici races: TTTTF, TRTTF, QFCSC, and MCCFC. A high frequency of the accessions (78.7% of T. monococcum and 93.0% of T. urartu) were resistant to P. graminis f. sp. tritici race TTKSK, with infection types ranging from 0 to 2+. Among these resistant accessions, 55 T. monococcum accessions (6.4% of the total) were also resistant to the other four races. Associations of resistance in T. monococcum germplasm to different races indicated the presence of genes conferring resistance to multiple races. Comparing the observed infection type patterns to the expected patterns of known genes indicated that previously uncharacterized genes for resistance to race TTKSK exist in both T. monococcum and T. urartu.


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.


1994 ◽  
Vol 74 (4) ◽  
pp. 671-673 ◽  
Author(s):  
P. L. Dyck

Accession 8404 of Triticum turgidum ssp. dicoccoides was shown to have excellent resistance to leaf rust. Genetic analysis of the F3 of 8404 and RL6089, a leaf rust susceptible durum, indicated that 8404 had three genes for leaf rust resistance. Two of these genes were transferred to hexaploid wheat (Thatcher) by a series of backcrosses. One of the genes transferred was the same as Lr33 (RL6057). The second gene, which gives a fleck reaction to avirulent P. recondita races, appears to be fully incorporated into the hexaploid where it segregated to fit a one-gene ratio. Backcross lines with this gene give excellent resistance to leaf rust, although race MBG is virulent to this gene. This may be a previously unidentified leaf rust resistance gene and should increase the genetic diversity available for wheat breeders. Key words:Triticum aestivum, wheat, Triticum turgidum ssp. dicoccoides, leaf rust resistance


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