Method for breeding ornamental rape flowers

The invention discloses a method for breeding ornamental rape flowers. The method comprises the following steps: artificially synthesizing a purple-leaf cabbage rape line through distant hybridizationof purple pakchoi and cabbage rapes, and breeding generations F1 to F7; respectively hybridizing the line of the generation F7 with a big-flower cabbage rape line and the cabbage rape line with highquality to obtain hybridized seeds of a new generation F1; starting to back-cross the hybridized seeds of the new generation F1, and gradually selecting new generations F2 to F4 to a purple-leaf big-flower landscape cabbage rape line. The method has the advantages that: (1) purple leaves are added, the stems are in purple, and the ornamental nature of rapes is increased; (2) the agronomic traits are excellent, the stress resistance is good, the erucic acid content in the seeds is low, and the glucosinolate content is low, and the ornamental rape belongs to double-low high-quality rapes which can produce high-quality ra