Method for breeding new purple-orange Chinese cabbage germplasm

A method for breeding purple-orange Chinese cabbage, comprises the steps:

• 1) crossing the orange Chinese cabbage inbred line 11J11, representative seed of the inbred line having been deposited under China Center for Type Culture Collection (CCTCC) Registration Number P202505, as the female parent and the purple-head Chinese cabbage inbred line 11S96, representative seed of the inbred line having been deposited under China Center for Type Culture Collection (CCTCC) Registration Number P202514, as the male parent to obtain F1 generation plants;
• planting the F1 generation seeds to obtain F1 generation plants, and selecting a plurality of individual F1 generation plants with a resistance to a disease selected from the group consisting of viral diseases, soft rot, and downy mildew, and good head firmness;
• 2) selfing the individual plants obtained in step 1) to obtain the seeds of a F2 population;
• planting the seeds of the F2 population to obtain F2 generation plants, and selecting a plurality of individual F2 generation plants carrying both the orange gene and purple-head gene;
• wherein the orange gene is a Brcritso gene having a nucleotide sequence shown in SEQ ID NO. 8 of the sequence listing;
• and
• wherein the purple-head gene is a BrMYB2 gene having a nucleotide sequence shown in SEQ ID NO. 9 of the sequence listing;
• and
• 3) selfing the individual F2 generation plants selected in step 2) to obtain the seeds of a F2S1 population;
• planting the seeds of the F2S1 population to obtain F2S1 generation plants, and selecting a plurality of individual F2S1 generation plants carrying both the orange gene and purple-head gene;
• 4) selfing the individual F2S1 generation plants selected in step 3) to obtain the seeds of a F2S2 population;
• planting the seeds of the F2S2 population to obtain F2S2 generation plants, and selecting a plurality of individual plants from the F2S2 generation plants carrying both the orange gene and purple-head gene;
• and
• 5) selfing the individual plants obtained in step 4) to obtain the seeds of a F2S3 population;
• plant the seeds of the F2S3 population to obtain F2S3 generation plants and both the orange gene and purple-head gene and with uniform horticultural traits from the F2S2 generation plants to obtain the purple-orange Chinese cabbage.