Identification and mapping of a novel blackleg resistance locus LepR4 in the progenies from Brassica napus × B. rapa subsp. sylvestris.

Blackleg, caused by Leptosphaeria maculans, is one of the most economically important diseases of Brassica napus worldwide. Two blackleg-resistant lines, 16S and 61446, were developed through interspecific hybridization between B. napus and B.