A method for identifying oat varieties with improved resistance to oat crown rust from a series of field trials

Race-specific resistance to crown rust, the most important disease of oat (Avena sativa) in Bra-zil, often fails within a few years of use in Brazilian cultivars. Virulence of 144 isolates of Puccinia coronata from cultivated oat in Brazil in 1997 to 1999 and 36 isolates from Uruguay in 1994-95 and 1998 was tested on a set of 27 oat crown rust differentials lines, each with a different Pc gene for race-specific resistance. Frequencies of virulence and mean virulence complexity were compared among these five collections from Brazil and Uruguay as well as with mean virulence complexity for a collection of 17 isolates from cultivated oat in western Siberia in Russia. Virulence-avirulence for each of the 27 Pc genes was polymorphic in both Brazil and Uruguay. Virulence frequencies were similar for collections from Brazil in 1998 and 1999 and for the collection from Uruguay from 1998, but there were large differences between the 1997 collection and the 1998 and 1999 collections from Brazil. Mean virulence complexity in both Brazil and Uruguay was greater than reported in the United States and much greater than in the Russian collection of P. coronata. A large number of races of P. coronata were found, with no more than five isolates of any race found in a single year in Brazil or Uruguay. The high virulence complexity and great diversity of virulence polymorphisms in Brazil and Uruguay make it unlikely that race-specific resistance can be effective there even though the South American populations of P. coronata are apparently entirely asexual.

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CROWN RUST ON PERENNIAL RYEGRASS IN FIELD TRIALS

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1989.50.1867 ◽

1989 ◽

pp. 253-254

Author(s):

H.S. Easton ◽

B.M. Cooper ◽

T.J. Frasers ◽

K.H. Widdup

Keyword(s):

Perennial Ryegrass ◽

Field Trials ◽

Crown Rust ◽

Puccinia Coronata ◽

Rust Infection

Crown rust infection of 11 perennial ryegrass cultivars vaned significantly and consistently over 6 sites. 'Grasslands Ariki,' the new cultivar 'Yatsyn' and Grasslands selections G26 and G33 were less infected than 'Grasslands Nui', 'Ellett' or 'Grasslands Ruanui'. 'Droughtmaster' and 'Marathon' proved more susceptible than most. Keywords: Crown rust, Puccinia coronata. perenmal ryegrass

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INHERITANCE OF CROWN RUST RESISTANCE IN THREE ACCESSIONS OF AVENA STERILIS

Canadian Journal of Genetics and Cytology ◽

10.1139/g80-005 ◽

1980 ◽

Vol 22 (1) ◽

pp. 27-33 ◽

Cited By ~ 26

Author(s):

D. E. Harder ◽

R. I. H. McKenzie ◽

J. W. Martens

Keyword(s):

Rust Resistance ◽

Dominant Gene ◽

Crown Rust ◽

Inheritance Of Resistance ◽

Single Dominant Gene ◽

Avena Sterilis ◽

Oat Crown Rust ◽

Crown Rust Resistance ◽

Resistance Spectrum ◽

Dominant Genes

The inheritance of resistance to oat crown rust was studied in three accessions of Avena sterilis L. Accession CAV 4274 originated from Morocco, CAV 4540 from Algeria, and CAV 3695 from Tunisia. Seedling rust tests on F2 backcross families indicated the presence of two dominant genes for crown rust resistance in CAV 4274. One of these, a gene conditioning resistance to most races tested, was linked or allelic to gene Pc-38, and was designated gene Pc-62. The second gene conferred resistance only to one of the six races studied, and was not tested further. In CAV 4540, a single dominant gene, Pc-63 was possibly allelic with Pc-62 and linked or allelic to Pc-38. Genes Pc-62 and 63 are generally similar to Pc-38 in their resistance spectrum, but these three genes are differentiated by races CR 102, CR 103, and CR 107. A single dominant gene in CAV 3695 appeared to be Pc-50.

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Filipin-sterol complexes in bean rust- and oat crown rust-fungal/plant interactions: Freeze-etch electron microscopy

PROTOPLASMA ◽

10.1007/bf01280214 ◽

1982 ◽

Vol 112 (1-2) ◽

pp. 46-54 ◽

Cited By ~ 23

Author(s):

D. E. Harder ◽

K. Mendgen

Keyword(s):

Electron Microscopy ◽

Crown Rust ◽

Plant Interactions ◽

Bean Rust ◽

Oat Crown Rust

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Variation and Distribution of the Oat Crown Rust-Fungus, Puccinia Coronata Avenae,in Britain in Relation to Breeding Resistant Oat Cultivars

Proceedings of the Second International Oats Conference ◽

10.1007/978-94-009-4408-4_17 ◽

1986 ◽

pp. 81-82

Author(s):

B. C. Clifford

Keyword(s):

Rust Fungus ◽

Crown Rust ◽

Puccinia Coronata ◽

Oat Crown Rust ◽

Puccinia Coronata Avenae ◽

Oat Cultivars

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Assessment of virulence patterns in crown rust populations

Canadian Journal of Botany ◽

10.1139/b68-089 ◽

1968 ◽

Vol 46 (5) ◽

pp. 613-617 ◽

Cited By ~ 2

Author(s):

George Fleischmann

Keyword(s):

Crown Rust ◽

Puccinia Coronata ◽

Western Canada ◽

Differential Host ◽

Oat Crown Rust ◽

Virulence Pattern ◽

Continued Use ◽

Race Identification

Two methods of determining the virulence pattern of oat crown rust, Puccinia coronata f. sp. avenae, populations collected in 1965, 1966, and 1967, in Eastern and Western Canada were compared. The results with a single-pustule isolate from each of 50 field collections were as accurate as those obtained with two single-pustule isolates from 100 or more field collections. The continued use of Bond and Ukraine as differential host varieties is of little value except for purposes of race identification, because they are attacked by most of the isolates.

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