GENES FOR STEM RUST RESISTANCE IN WHEAT VARIETIES HOPE AND H-44

1971 ◽  
Vol 13 (2) ◽  
pp. 186-188 ◽  
Author(s):  
D. R. Knott

Tests were carried out to identify and locate the genes for resistance to races 15B-1L and 56 in Hope and H-44. The gene Sr1 which conditions resistance to race 56 was found to be either very closely linked or more probably allelic to Sr9. It is proposed that it be redesignated Sr9d. The gene Sr2 which conditions adult plant resistance to race 56 appears to be on chromosome 3B. The recessive gene conditioning resistance to race 15B-1L was identified as sr17 which is on chromosome 7B.

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.


Plant Disease ◽  
2021 ◽  
Author(s):  
Yahya Rauf ◽  
Prabin Bajgain ◽  
Matthew Rouse ◽  
Khalil A Khanzada ◽  
Sridhar Bhavani ◽  
...  

Adult plant resistance (APR) to wheat stem rust has been one of the approaches for resistance breeding since the evolution of the Ug99 race group and other races. This study was conducted to dissect and understand the genetic basis of APR to stem rust in spring wheat line ‘Copio’. A total of 176 recombinant inbred lines (RIL) from the cross of susceptible parent ‘Apav’ with Copio were phenotyped for stem rust resistance in six environments. Composite interval mapping (CIM) using 762 Genotyping-by-Sequencing (GBS) markers, identified 16 genomic regions conferring stem rust resistance. Assays with gene-linked molecular markers revealed that Copio carried known APR genes Sr2 and Lr46/Yr29/Sr58 in addition to the 2NS/2AS translocation that harbors race-specific genes Sr38, Lr37 and Yr17. Three QTL were mapped on chromosomes 2B, two QTL on chromosomes 3A, 3B, and 6A each, and one QTL on each of chromosomes 2A, 1B, 2D, 4B, 5D, 6D and 7A. The QTL QSr.umn.5D is potentially a new resistance gene and contributed to quantitative resistance in Copio. The RILs with allelic combinations of Sr2, Sr38, and Sr58 had 27-39% less stem rust coefficient of infection in all field environments compared to RILs with none of these genes and this gene combination was most effective in the US environments. We conclude that Copio carries several genes that provide both race-specific and non-race-specific resistance to diverse races of stem rust fungus and can be used by breeding programs in pyramiding other effective genes to develop durable resistance in wheat.


1997 ◽  
Vol 77 (2) ◽  
pp. 289-292
Author(s):  
D. R. Knott

The wheat (Triticum aestivum L.) cultivars Bonza and Chris have adult plant resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) in addition to genes for specific resistance. Both cultivars were crossed to a susceptible wheat, LMPG. Lines carrying the adult plant resistances of the two parents were produced by selecting for seedling susceptibility in the greenhouse and adult plant resistance in the field to race 15B-1 (TMH). Three homozygous lines derived from Bonza and two from Chris were crossed and backcrossed to LMPG. Backcross F2 families were grown in a field nursery inoculated with a multi-race mixture of eight stem rust isolates including 15B-1. Stem rust severities in percent were recorded. An analysis of the data indicated that adult plant resistance of Bonza was controlled by a single recessive gene and that of Chris by two complementary recessive genes. Since the resistance was effective against a complex mixture of virulent stem rust races, it should be of interest to wheat breeders. Key words: Stem rust, Puccinia graminis, common wheat, Triticum aestivum, adult plant resistance


2007 ◽  
Vol 58 (6) ◽  
pp. 576 ◽  
Author(s):  
H. S. Bariana ◽  
G. N. Brown ◽  
U. K. Bansal ◽  
H. Miah ◽  
G. E. Standen ◽  
...  

Stem rust susceptibility of European wheats under Australian conditions posed a significant threat to wheat production for the early British settlers in Australia. The famous Australian wheat breeder, William Farrer, tackled the problem of stem rust susceptibility through breeding fast-maturing wheat cultivars. South-eastern Australia suffered a severe stem rust epidemic in 1973, which gave rise to a national approach to breeding for rust resistance. The National Wheat Rust Control Program was set up in 1975, modelled on the University of Sydney’s own rust resistance breeding program, at the University of Sydney Plant Breeding Institute, Castle Hill (now Cobbitty). Back-crossing of a range of sources of resistance provided genetically diverse germplasm for evaluation in various breeding programs. Current efforts are directed to building gene combinations through marker-assisted selection. Major genes for resistance to stem rust and leaf rust are being used in the back-crossing program of the ACRCP to create genetic diversity among Australian germplasm. Stripe rust and to a lesser extent leaf rust resistance in the Australian germplasm is largely based on combinations of adult plant resistance genes and our knowledge of their genomic locations has increased. Additional genes, other than Yr18/Lr34 and Yr29/Lr46, appeared to control adult plant resistance to both leaf rust and stripe rust. Two adult-plant stem rust resistance genes have also been identified. The development of selection technologies to achieve genotype-based selection of resistance gene combinations in the absence of bioassays has evolved in the last 5 years. Robust molecular markers are now available for several commercially important rust resistance genes. Marker-assisted selection for rust resistance is performed routinely in many wheat-breeding programs. Modified pedigree and limited back-cross methods have been used for breeding rust-resistant wheat cultivars in the University of Sydney wheat-breeding program. The single back-cross methodology has proved more successful in producing cultivars with combinations of adult plant resistance genes.


1959 ◽  
Vol 37 (6) ◽  
pp. 1153-1155 ◽  
Author(s):  
D. J. Samborski ◽  
W. Ostapyk

Unexpectedly heavy leaf rust development was observed on mature (ripe) field-grown plants of the resistant wheat varieties, Selkirk and Exchange. Greenhouse experiments with pure races of leaf rust showed that a partial breakdown of both seedling and adult plant resistance occurred when the plants were approaching maturity. This change in resistance would not affect yields but could result in exaggerated estimates of rust damage. Leaf rust readings in rust nurseries, at least on these varieties, should be made before the plants are ripe.


Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 90-93 ◽  
Author(s):  
A. L. Barcellos ◽  
A. P. Roelfs ◽  
M. I. B. de Moraes-Fernandes

Adult plant resistance to leaf rust in the Brazilian wheat cultivar Toropi (Triticum aestivum) was studied in crosses with the susceptible cultivar IAC 13. Cvs. Toropi and IAC 13 are susceptible at the seedling stage to race LCG-RS of Puccinia triticina Erikss., and to all other known Brazilian leaf-rust races. Thus, the resistance observed in Toropi in the field was due to adult plant-resistance genes. In the greenhouse at the adult plant stage, resistance segregated in a 7:9 ratio for two complementary recessive genes. Additionally, two recessive genes for leaf-tip necrosis were identified in the greenhouse environment. Necrosis was expressed when the two homozygous recessive genes occurred together in the F2, independently of the response to leaf rust. The resistance and leaf-necrosis genes differ from those previously reported in wheat. Segregation for leaf-rust resistance in the field at Passo Fundo, Brazil, fit a 1:3 ratio for a single recessive gene. With a different pathogen race, and in crosses of cvs. Toropi and ThatcherLr34, two recessive genes and a dominant gene for resistance were detected in the field in Mexico. The dominant gene was likely Lr34 from cv. ThatcherLr34 and the two recessive genes were likely those detected in the greenhouse adult plants tests at Passo Fundo.


1971 ◽  
Vol 49 (10) ◽  
pp. 1783-1785 ◽  
Author(s):  
D. E. Harder ◽  
J. W. Martens ◽  
R. I. H. McKenzie

The expression of adult plant oat stem rust resistance conferred by gene pg-11 is associated with a reduction of chlorophyll and carotenoid pigments in the leaf and stem tissue. Seedlings that possess gene pg-11 are susceptible to stem rust and have near normal pigment levels but with increasing age the pigment content decreases more rapidly than in plants without the gene and the plants become moderately resistant to stem rust. The ratio of chlorophyll to carotenoids remains unchanged at all stages of plant development. This gene has effects unlike any other known gene for stem rust resistance in oats.


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