Genes for stem rust resistance in Thatcher wheat

2009 ◽  
Vol 89 (6) ◽  
pp. 1003-1008
Author(s):  
D R Knott

The common wheat (Triticum aestivum L.) cultivar Thatcher has resistance to many of the older races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.). Several genetic studies have shown that its resistance is complex in inheritance. To attempt to clarify the inheritance, 28 lines, each believed to carry a single resistance gene from Thatcher, were developed. The lines were tested with 13 races of stem rust. They fell into 13 types with resistance to from 1 to 11 races. Of the five genes previously identified in Thatcher, only two, Sr9g, and Sr12, were present in the lines. Four lines carried named genes, Sr6, Sr7a, Sr8a and S9d, which had not previously been detected in Thatcher. Thatcher is resistant to 8 of the 13 races. At least one line was resistant to each of the 13 races, including the five to which Thatcher is susceptible. Eleven of the 13 types of lines were resistant to race MCCD to which Thatcher is resistant. Seven of the types were resistant to race TMRT(15B-1) to which Thatcher is susceptible. Clearly, the inheritance of resistance in Thatcher is very complex and involves a considerable number of genes. It carries a surprising number of genes that appear to be hidden by the presence of suppressor genes or transposons.Key words: Common wheat, Triticum aestivum, Puccinia graminis, suppressors, tansposons

1975 ◽  
Vol 17 (4) ◽  
pp. 667-674 ◽  
Author(s):  
P. L. Dyck ◽  
G. J. Green

The genetics of resistance to stem rust (Puccinia graminis tritici) was investigated in wheat (Triticum aestivum L.) cultivars Romany, Es.P 518/9, Bonny and Tama that are resistant to many races in both Canada and Kenya. Seedling resistance in the four cultivars to 12 Canadian races is controlled primarily by previously identified genes. The results indicate that the cultivars have the following genes: Romany — Sr5, Sr6, Sr7a, Sr9b and SrW; Es.P 518/9 — Sr5, Sr6, Sr7a, Sr8, Sr9b, SrW and possibly Sr17; Bonny — Sr6 and Sr11; and Tama — Sr6 and Sr8. Gene SrW confers moderate resistance and is also present in the cultivar Webster.


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.


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 ◽  
1989 ◽  
Vol 32 (5) ◽  
pp. 932-933 ◽  
Author(s):  
D. R. Knott

A type of dwarfism found in crosses involving the wheat (Triticum aestivum L.) cultivar Webster and a stem rust (Puccinia graminis tritici Erik. &Henn.) susceptible line, LMPG, proved to be due to a dominant gene from cv. Webster and a recessive gene from LMPG. The dominant gene is closely linked to the gene Sr30, which conditions stem rust resistance in cv. Webster and is on chromosome 5D. The dwarf plants have short, dark green, stiff leaves and rarely develop more than two leaves before dying.Key words: dwarfism, Triticum aestivum, Puccinia graminis tritici, stem rust.


1970 ◽  
Vol 50 (3) ◽  
pp. 229-232 ◽  
Author(s):  
P. L. DYCK ◽  
G. J. GREEN

The inheritance of resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.) was investigated in Triticum aestivum L. cv. Red Bobs. It carries a gene for stem rust resistance at the Sr7 locus that resembles Sr7b of Marquis, and a gene that is either Sr10 or, more likely, an allele, because Red Bobs is less resistant than the Marquis-Sr10 line to races C1 (17) and C17 (56).


1984 ◽  
Vol 26 (2) ◽  
pp. 174-176 ◽  
Author(s):  
D. R. Knott

The common wheat (Triticum aestivum L.) cultivar 'Marquillo' was crossed and backcrossed to 'Marquis,' and was also crossed with the 'Chinese Spring' monosomics. Seedlings from the F2 families from the backcross and from F2 and F3 families from the crosses with the monosomics were tested with race 56 of stem rust (Puccinia graminis tritici Eriks. and Henn.). The results indicated that 'Marquillo' carries a single recessive gene for resistance to race 56, located on chromosome 3B. The gene which was identified as Sr12, appears to be temperature sensitive and was affected by a recessive modifier.Key words: wheat, Triticum aestivum, Puccinia graminis, monosomics, rust resistance.


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.


2000 ◽  
Vol 80 (1) ◽  
pp. 53-63 ◽  
Author(s):  
D. R. Knott

Thatcher was the predominant wheat (Triticum aestivum L.) cultivar on the Canadian prairies in the 1950s. Until race 15B (TMH) of stem rust (Puccinia graminis pers. f. sp. tritici Eriks. & Henn.) became widespread, Thatcher had good resistance to stem rust, but was susceptible to leaf rust (P. recondita f. sp. tritici Rob. ex Desm.). Although genes for stem rust resistance have been identified in Thatcher, the inheritance of its resistance has never been fully understood. The objective of this research was to attempt to elucidate the inheritance of the resistance of Thatcher and to determine why it had a reputation as a poor parent for rust resistance. Over a period of 40 yr, crosses and backcrosses to a susceptible genotype and two sets of single seed descent (SSD) lines were studied. The second set of SSD lines was tested with isolates of six races of stem rust to which Thatcher is resistant. The data showed that Thatcher is a very heterogenous cultivar with individual plants differing widely in the genes for stem rust resistance that they carry. The inheritance of rust resistance varied greatly from race to race and was often quite complex. Either complementary genes or a gene plus a suppressor appeared to condition resistance to one race. Most genes gave resistance to only one race. The presence of Sr5, which Thatcher is known to have obtained from Kanred, was confirmed. Most of its many additional genes probably came from Iumillo durum wheat. Key words: Stem rust, Thatcher wheat, single seed descent


2012 ◽  
Vol 92 (6) ◽  
pp. 1037-1041 ◽  
Author(s):  
Habibollah Ghazvini ◽  
Colin W. Hiebert ◽  
Taye Zegeye ◽  
Tom Fetch

Ghazvini, H., Hiebert, C. W., Zegeye, T. and Fetch, T. 2012. Inheritance of stem rust resistance derived from Aegilops triuncialis in wheat line Tr129. Can. J. Plant Sci. 92: 1037–1041. Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a devastating disease of wheat that can cause serious grain yield reduction. The emergence of Pgt race TTKSK (Ug99) and new variants in Africa is considered a threat to wheat production worldwide. Among the primary gene pool of wheat, only a few stem rust resistance (Sr) genes confer resistance to TTKSK. Wild relatives of common wheat are an important source of disease resistance. A preliminary study indicated that the common wheat line Tr129, which contains one or more Aegilops triuncialis translocations, is resistant to race TTKSK. The goal of this study was to elucidate the inheritance of resistance to Pgt in line Tr129 and investigate the novelty of the gene(s) conferring resistance. A population was generated by crossing RL6071 with Tr129 and F2 and F3 progeny were inoculated with Pgt race MCCF at the first leaf stage. Segregation of F2 plants fit a 15:1 ratio ([Formula: see text]=1.48, P=0.22) indicating two dominant genes in Tr129 conditioned stem rust resistance to race MCCF. Segregation of F3 families also fit a 7:8:1 ratio ([Formula: see text]= 3.28, P=0.19) confirming the presence of two dominant genes. This is first report of stem rust resistance transferred to wheat from Ae. triuncialis.


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