Suggestions for Determination and Terminology of Pathotypes and Genes for Resistance in Cyst‐forming Nematodes, especially Heterodera avenae1

Abstract

A short review of differentiation into pathotypes is given. Use of the word ≪ pathotype ≫ is recommended when a very clear difference is established between virulence of nematode populations. Our present knowledge makes it possible to differentiate between 10 pathotypes of Heterodera avenae. It is suggested that the pathotypes are given numbers, and corresponding terms should be used for genes for resistance in plants, e.g. a gene Hal on the barley chromosome gives resistance to nematode pathotypes 11,21,31,41 etc. Some proposals for improvement of pathotype identification are given.