Diseases

Blackleg of rapeseed

Brassica napus var. napus

A fungal disease of rapeseed, also known as phoma stem canker, caused primarily by the pathogen Leptosphaeria maculans. It affects all plant organs, causing necrosis of the root collar, lodging of stems, and seedling death.

In the reference 16 varieties crop Rapeseed, where this is mentioned in the description.

The disease pathogen is the fungus Leptosphaeria maculans, which also has an anamorph stage Phoma lingam. The infection manifests on seedlings as blackleg, forms light-colored spots with black pycnidia on leaves, and sunken spots with concentric zonation on pods. The most dangerous form of the infection is stem canker, where necrosis of the root collar makes the stem hollow and brittle, leading to crop lodging.

The interaction between rapeseed and the pathogen is described by the gene-for-gene system, which results in the existence of numerous fungal races. Breeding utilizes race-specific Rlm resistance genes, such as Rlm1, Rlm2, Rlm3, Rlm4, and Rlm7, as well as quantitative resistance provided by a group of minor-effect genes. Modern breeding strategies are focused on pyramiding multiple genes to increase the durability of protection.

General information about the subject — on the page Dry rot.

Sources8

Varieties of Rapeseed mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.