Genetic analysis of barley mutants with modifications of powdery mildew resistance gene Ml-a12

Abstract

Fifteen mutants with increased powdery mildew susceptibility (infection types between 0–1 and 3–4) were crossed with the Ml-a12 resistant mother line 'Sultan-5' (infection type 0) and the susceptible variety 'Carlsberg II'. Analysis of the material revealed that 13 mutants had mutational modifications of the Ml-a12 gene. Two mutants had a suppressor-mutant gene that modified the phenotypic expression of gene Ml-a12. One suppressor gene was recessive, the other was semidominant. The possible function of gene Ml-a12 is discussed.Key words: barley, Hordeum vulgare, powdery mildew, Erysiphe graminis hordei, mutation, resistance, suppressor.