Submitted to: Canadian Phytopathological Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/10/1997
Publication Date: N/A
Technical Abstract: A nomenclature system for designating virulence combinations of isolates of Puccinia coronata f.sp. avenae in North America is proposed. Sixteen single gene oat lines with Pc38, Pc39, Pc40, Pc45, Pc46, Pc48, Pc50, Pc51, Pc52, Pc54, Pc56, Pc58, Pc59, Pc62, Pc64, and Pc68 are the primary differentials. Races of P. coronata are determined based on high (virulence) or low (avirulence) infection types on the differentials, which are arranged in four subsets of four. For each subset of differentials, a letter is assigned representing a specific pattern of high or low infection types. The consonants B through T indicate the 16 possible infection type patterns on each subset, with letters assigned in a binary series from B = all low infection types to T = all high infection types. Virulence combinations over the 16 primary differentials are assigned with a four-letter code, prefixed by a Pca designation for races of P. coronata. Additional differentials can be accommodated by adding a slash after the Pca code followed by designations for the supplemental differentials. The 10 letters not used in the Pca codes can be used in sequence as identifiers of the current differential set to distinguish it from modified differential sets that may replace it in the future.