Molecular marker closely linked with brassica napus branching angle character QTL site and application

The invention discloses a molecular marker closely linked with a brassica napus branching angle character QTL site and application, and relates to the technical field of molecular markers, and the technical scheme is characterized in that BSA-seq and QTL positioning is performed by constructing a mixed pool for a large-branching-angle parent L4073 and a small-branching-angle parent L4070 of a brassica napus variety and a filial generation population; a new branching angle site qBA.C03 is found on a C3 chromosome, two molecular markers C3-18 and C3-21 which are closely linked with the branching angle are developed according to the site, the molecular markers can be applied to genotype identification of rape after hybridization of two parents, the screening efficiency of the brassica napus branching angle is greatly improved, and the screening cost is reduced. The invention provides a new genetic marker for compact plant type breeding of the brassica napus, and also provides a basis for fine positioning of bran