scholarly journals Lr46: A Gene Conferring Slow-Rusting Resistance to Leaf Rust in Wheat

1998 ◽  
Vol 88 (9) ◽  
pp. 890-894 ◽  
Author(s):  
R. P. Singh ◽  
A. Mujeeb-Kazi ◽  
J. Huerta-Espino

Wheat (Triticum aestivum) cultivar Pavon 76 carries slow-rusting resistance to leaf rust that has remained effective in Mexico since its release in 1976. ‘Pavon 76’ was crossed with two leaf rust-susceptible wheat cultivars, Jupateco 73S and Avocet S, and between 118 and 148 individual F2 plant-derived F3 and F5 lines were evaluated for adult-plant leaf rust resistance at two field sites in Mexico during different seasons. Evaluation of F1 plants and parents indicated that the slow-rusting resistance was partially dominant. Segregation in the F3 and F5 indicated that the resistance was based on two genes with additive effects. Monosomic analysis was carried out to determine the chromosomal locations of the resistance genes. For this purpose, two or three backcross-derived cytogenetic populations were developed by crossing ‘Pavon 76’ with a monosomic series of adult-plant leaf rust-susceptible cultivar Lal-bahadur. Evaluation of such BC2F3 and BC3F3 lines from 16 confirmed ‘Lalbahadur’ monosomics indicated that one slow-rusting gene was located in chromosome 1B of ‘Pavon 76’. This gene, designated as Lr46, is the second named gene involved in slow-rusting resistance to leaf rust in wheat.

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 943
Author(s):  
Pakeerathan Kandiah ◽  
Mumta Chhetri ◽  
Matthew Hayden ◽  
Michael Ayliffe ◽  
Harbans Bariana ◽  
...  

Among the rust diseases, leaf rust of wheat caused by Puccinia triticina, is the most prevalent worldwide and causes significant yield losses. This study aimed to determine the genomic location of loci that control adult plant resistance (APR) to leaf rust in the pre-Green Revolution landrace accession, Aus27506, from the “Watkins Collection”. An Aus27506/Aus27229-derived F7 recombinant inbred line (RIL) population was screened under field conditions across three cropping seasons and genotyped with the iSelect 90K Infinium SNP bead chip array. One quantitative trait loci (QTL) on each of the chromosomes 1BL, 2B and 2DL explained most of the leaf rust response variation in the RIL population, and these were named QLr.sun-1BL, QLr.sun-2B and QLr.sun-2DL, respectively. QLr.sun-1BL and QLr.sun-2DL were contributed by Aus27506. QLr.sun-1BL is likely Lr46, while QLr.sun-2DL appeared to be a new APR locus. The alternate parent, Aus27229, carried the putatively new APR locus QLr.sun-2B. The comparison of average severities among RILs carrying these QTL in different combinations indicated that QLr.sun-2B does not interact with either of the other two QTL; however, the combination of QLr.sun-1BL and QLr.sun-2DL reduced disease severity significantly. In planta fungal quantification assays validated these results. The RILs carrying QLr.sun-1BL and QLr.sun-2DL did not differ significantly from the parent Aus27506 in terms of resistance. Aus27506 can be used as a source of adult plant leaf rust resistance in breeding programs.


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.


2014 ◽  
Vol 127 (5) ◽  
pp. 1133-1141 ◽  
Author(s):  
M. J. Diéguez ◽  
M. F. Pergolesi ◽  
S. M. Velasquez ◽  
L. Ingala ◽  
M. López ◽  
...  

Author(s):  
Pakeerathan Kandiah ◽  
Mumta Chhetri ◽  
Matthew Hayden ◽  
Michael Ayliffe ◽  
Harbans Bariana ◽  
...  

Among the rust diseases, leaf rust of wheat caused by Puccinia triticina, is the most prevalent worldwide and causes significant yield losses. This study aimed to determine the genomic location of loci that control adult plant resistance (APR) to leaf rust in the pre-Green Revolution landrace accession, Aus27506, from the ‘Watkins Collection’. An Aus27506/Aus27229-derived F7 recombinant inbred (RIL) population was screened under field conditions across three cropping seasons and genotyped with the iSelect 90K Infinium SNP bead chip array. One QTL on each of chromosomes 1BL, 2B and 2DL explained most of the leaf rust response variation in the RIL population and were named QLr.sun-1BL, QLr.sun-2B and QLr.sun-2DL, respectively. QLr.sun-1BL and QLr.sun-2DL were contributed by Aus27506. QLr.sun-1BL is likely Lr46, while QLr.sun-2DL appeared to be a new APR locus. The alternate parent, Aus27229, carried the putatively new APR locus QLr.sun-2B. Comparisons of average severities among RILs carrying these QTL in different combinations indicated that QLr.sun-2B does not interact with either of the other two QTL; however, the combination of QLr.sun-1BL and QLr.sun-2DL reduced disease severity significantly. In-planta fungal quantification assays validated these results. The RILs carrying QLr.sun-1BL and QLr.sun-2DL did not differ significantly from parent Aus27506 in resistance. Aus27506 can be used as a source of adult plant leaf rust resistance in breeding programs.


2020 ◽  
Vol 13 (3) ◽  
Author(s):  
Suraj Sapkota ◽  
Mohamed Mergoum ◽  
Ajay Kumar ◽  
Jason D. Fiedler ◽  
Jerry Johnson ◽  
...  

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1127-1133 ◽  
Author(s):  
L. M. Oelke ◽  
J. A. Kolmer

Leaf rust, caused by Puccinia triticina Eriks., is the most common disease of wheat (Triticum aestivum L.) in the United States and worldwide. The objective of this study was to characterize seedling and adult plant leaf rust resistance in hard red spring wheat cultivars grown in Minnesota, North Dakota, and South Dakota, and postulate the identity of the seedling leaf rust resistance genes in the cultivars. Twenty-six cultivars, near-isogenic lines of Thatcher wheat that differ for single leaf rust resistance genes, and three wheat cultivars with known leaf rust resistance genes, were tested with 11 different isolates of leaf rust collected from the United States and Canada. The leaf rust infection types produced on seedling plants of the cultivars in greenhouse tests were compared with the infection types produced by the same isolates on the Thatcher near-isogenic lines to postulate which seedling leaf rust resistance genes were present. Seedling leaf rust resistance genes Lr1, Lr2a, Lr10, Lr16, Lr21, and Lr24 were postulated to be present in spring wheat cultivars. Seedling genes Lr3, Lr14a, and Lr23 likely were present in some cultivars but could not be clearly identified in this study. Most of the cultivars had some level of adult plant leaf rust resistance, most likely due to Lr34. Cultivars that had seedling resistance genes Lr1, Lr2a, Lr10, or Lr16 had poor to intermediate levels of leaf rust resistance in field plots. Cultivars with combinations of seedling resistance genes Lr16 and Lr24 with additional adult plant resistance were highly resistant to leaf rust.


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