Pathogenic specialization of Puccinia hordei Otth. in Australia, 1966-1990
1995
Cotterill, P.J. | Rees, R.G. (Queensland Dept. of Primary Industries, Toowoomba (Australia). Queensland Wheat Research Inst.) | Park, R.F. (Sydney Univ. Plant Breeding Inst., Cobbitty (Australia))
A total of 154 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 Rph1 to Rph9, Rph12 (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 plus and P minus respectively. Eleven distinct pathotypes (pt) were identified, with Pt 243 P plus and 243 P minus predominating in samples collected between 1966 and 1979. In the 1980s, pt 210 P plus 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 plus was most frequent in this region. Virulences to genes Rph1, Rph2, Rph4, Rph5, Rph6, Rph8, Rph9 and Rph12 have been detected, and only Rph3 and Rph7 are likely to be of value in protecting future Australian barleys from the disease.
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