Investigating the phenotype of major gene-mediated resistance to Pyrenopeziza brassicae in Brassica napus

Pyrenopeziza brassicae causes light leaf spot on winter oilseed rape (Brassica napus), which is currently controlled through the use of fungicides and cultivars with quantitative resistance. Imola is a new oilseed rape cultivar, thought to contain at least one major resistance gene against P. brassicae. Previous work has shown that P. brassicae is unable to undergo asexual sporulation on cv. Imola and a “black flecking” phenotype (particularly apparent on leaf vein tissue) is instead observed after inoculation with P. brassicae conidia in controlled environment conditions