Relation Between Incidence of Gaeumannomyces Graminis Var. Tritlci and Grain Yield

Abstract

A method of using grain yield to estimate the incidence of G. graminis var. tritici in the field is described. It was found that a map based on yield alone underestimated the actual incidence. However, when incidence and grain yield were coupled by the use of an "incidence-yield" regression established on a few sites, a map showing estimated levels of G. graminis var. tritici was obtained without destroying the experimental area. Bioassays of stubble and of soil cores were used to establish the actual incidence of G. graminis var. tritici; the former gave better results.