3.3.1. Development of the DP30-CSSLs

The procedure we developed the DP30-CSSLs is shown in Figure 2. The F1 plants were obtained by crossing DP30 and 93-11. Molecular MAS began using the BC4F1, resulting in 176 BC5 F3 lines, 32 BC6 F3 lines and 22 BC7 F3 lines containing the target segments. Finally, we selected 132 CSSLs from these 230 lines (candidate plants) for genetic and phenotypic analysis (Figure 2, Table S3).

**Figure 2.** Schematic of the process used to develop DP30-CSSLs in this study. MAS—molecular marker-assisted selection; ×—hybrid; ⊗—self-crossing.
