GENETIC CONTROL OF VIRULENCE IN USTILAGO HORDEI. IV. DUPLICATE GENES FOR VIRULENCE AND GENETIC AND ENVIRONMENTAL MODIFICATION OF A GENE-FOR-GENE RELATIONSHIP

Abstract

Genotype V2v2 of Ustilago hordei was transferred to a new genetic background and its gene-for-gene interaction with genotype R2R2 of barley cultivar Excelsior was studied in two different environments. This gene-for-gene interaction was found to be subject to both genetic and environmental modification. The analysis also revealed that virulence which is specific to cultivars Keystone and Himalaya can be controlled by duplicate recessive genes present at either one of two genetic loci of U. hordei.