Pathogenic specialization of Puccinia hordei Otth. in Australia, 1966-1990

1995 ◽  
Vol 46 (1) ◽  
pp. 127 ◽  
Author(s):  
PJ Cotterill ◽  
RF Park ◽  
RG Rees
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
New South ◽  
New South Wales ◽  
Puccinia Hordei ◽  
Resistance Sources ◽  
South Wales ◽  
Rust Pathogen

One hundred and fifty-four isolates of the leaf rust pathogen (Puccinia hordei), collected from infected barley plants in Australia between 1966 and 1990, were typed to determine virulence with respect to the resistance genes Rphl to Rph9, Rphl2 (Triumph) and several uncharacterized resistance sources. The Australian cultivar, Prior, reacted differentially to the isolates examined, and is believed to possess a gene which is also present in addition to Rph2 in Reka 1. Virulence and avirulence on Prior were designated P+ and P- respectively. Eleven distinct pathotypes (pt) were identified, with pt 243 P+ and 243 P- predominating in samples collected between 1966 and 1979. In the 1980s, pt 210 P+ was most commonly isolated from samples collected in Queensland and northern New South Wales, and although a range of different pathotypes was present in southern Australia, pt 200 P+ was most frequent in this region. Virulences to genes Rphl, Rph2, Rph4, Rph5, Rph6, Rph8, Rph9 and Rphl2 have been detected, and only Rph3 and Rph7 are likely to be of value in protecting future Australian barleys from the disease.

scholarly journals Pathogenic Specialization and Pathotype Distribution of Puccinia hordei in Australia, 1992 to 2001

Plant Disease ◽  
2003 ◽  
Vol 87 (11) ◽  
pp. 1311-1316 ◽  
Author(s):  
R. F. Park
Keyword(s):  
Resistance Genes ◽  
New South ◽  
South Australia ◽  
Resistance Breeding ◽  
Puccinia Hordei ◽  
Significant Shift ◽  
Seedling Resistance ◽  
South Wales ◽  
Rust Pathogen ◽  
Pathogenic Variability

Annual surveys of pathogenic variability in the leaf rust pathogen of barley, Puccinia hordei, from 1992 to 2001 revealed a significant shift in the composition of populations across Austra-lia. Virulence for the resistance gene Rph12, first detected in a single pathotype, 4610P+, in Tasmania in 1991, was subsequently detected in 1993 in South Australia, Victoria, and southern New South Wales. By the end of 2001, eight pathotypes with virulence for Rph12 had been isolated, and virulence for this gene was present in all Australian barley growing regions. Virulence was not detected for the resistance genes Rph3, Rph7, Rph11, or Rph14. The distribution and spread of the pathotypes detected, their possible origins, pathogenicity on several uncharacterized seedling resistance sources, and implications for resistance breeding are discussed.

scholarly journals Changes in the Racial Composition of Phytophthora sojae in Australia Between 1979 and 1996

Plant Disease ◽  
1998 ◽  
Vol 82 (9) ◽  
pp. 1048-1054 ◽  
Author(s):  
M. J. Ryley ◽  
N. R. Obst ◽  
J. A. G. Irwin ◽  
A. Drenth
Keyword(s):  
Resistance Genes ◽  
Specific Resistance ◽  
New South ◽  
New South Wales ◽  
Phytophthora Sojae ◽  
South Wales ◽  
Eastern Australia ◽  
Race 1 ◽  
New Races ◽  
Race 4

Surveys of commercial soybean fields, disease nurseries, and trial plots of soybean were conducted throughout eastern Australia between 1979 and 1996, and 694 isolates of Phytophthora sojae were collected and classified into races. Fourteen races, 1, 2, 4, 10, 15, and 25, and eight new races, 46 to 53, were identified, but only races 1, 4, 15, 25, 46, and 53 were found in commercial fields. Races 1 and 15 were the only races found in commercial fields in the soybean-growing areas of Australia up until 1989, with race 1 being the dominant race. Race 4 was found in central New South Wales in 1989 on cultivars with the Rps1a gene, and it is now the dominant race in central and southern New South Wales. Races 46 and 53 have only been found once, in southern New South Wales, and race 25 was identified in the same region in 1994 on a cultivar with the Rps1k gene. Only races 1 and 15 have been found in the northern soybean-growing regions, with the latter dominating, which coincides with the widespread use of cultivars with the Rps2 gene. Changes in the race structure of the P. sojae population from commercial fields in Australia follow the deployment of specific resistance genes.

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