## 3 Results
### Agronomic Traits and Yield Performance in the Field  
Purple broccoli pure lines and green broccoli lines with excellent agronomic traits were selected and planted in plots for _F3\({}^{\prime}\)H_ and _Pur7.1_ gene identification and determination of major agronomic traits, such as plant height, plant spread, head height, head diameter, head shape, head color, anthocyanin content, stalk diameter, glucoraphanin content, and head weight. The mean anthocyanin contents of the three parents, BT126, SN60, and LF02, were 63, 1.5, and 12 mg/100 g FW, and the selected purple progeny lines had 46-71 mg/100 g FW, with one exceeding that of their donor parent BT126. In contrast, the mean anthocyanin contents of the two selected green progeny lines without purple-green heads at low temperature were 1.3 and 1.7 mg/100 g FW. The mean head weights were 400, 450.2, and 620 g, respectively, whereas the selected progeny lines had mean head weights of 523.3-617.3 g, which is a desirable range for breeding traits. The mean head diameters for the three parents were 13.85, 12.25, and 15.9 cm, respectively, and the head diameters in the selected progeny lines ranged from 14.37 to 15.45. The mean head lengths for each parent were 6.36, 7.03, and 10.72 cm. Their selected plants had head lengths mostly between 8.48 and 10.2 cm. The mean glucoraphanin contents for the three parents were 8.75, 3.24, and 7.32, respectively, while the mean glucoraphanin content for their selected progeny lines mainly ranged from 4.65 to 7.11 umol/g DW. The head shapes for the three parents were flat, round, and round, respectively, while the selected progeny lines had round or semi-round head shapes, which were more attractive than their donor parents (Table 3). The results showed that the anthocyanin contents of the three new purple broccoli lines, 20 PBL23, 20 PBL62, and 20 PBL103, and the two new green broccoli lines, 20 GBL47 and 20 GBL128, were significantly different from those of the LF02, while the main agronomic traits were not significantly different from those of the LF02 (Figure S1). Their agronomic traits were similar or superior to their elite parents, providing more options for broccoli breeding. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Parents and** **Lines** & **Growth** & **Plant** & **Plant** & **Head** & **Head** & **Stalk** & **Anthocyanin** & **Head** & **Glucorapanin** & **Head** \\
**Lines** & **Period (d)** & **Height** & **Spread** & **Length** & **Diameter** & **Head Shape** & **Diameter** & **Content** & **(mg/100 g FW)** & **Head** & **Weight** \\  & & & & & & & & **(cm)** & **(cm)** & **(mg/100 g FW)** & & **(mm/100 g DW)** & **(g)** \\ \hline \multicolumn{10}{c}{Purple broccoli} \\ \hline BT126 & 90-100 & 63.2 & 82.03 & 6.36 & 13.85 & Flat & 4.13 & 63 & Purple & 8.75 & 400.0 \\
20 PBL23 & 90-100 & 62.4 \({}^{\ast}\) & 90 \({}^{\ast}\) & 8.4 \({}^{\ast}\) & 14.62 \({}^{\ast}\) & Round & 4.63 \({}^{\ast}\) & 46 \({}^{\ast}\) & Purple & 7.11 & 523.3 \\
20 PBL2 & 90-100 & 68.5 & 78 \({}^{\ast}\) & 10.2 & 15.45 \({}^{\ast}\) & Round & 5.1 \({}^{\ast}\) & 57 \({}^{\ast}\) & Purple & 5.26 & 617.3 \\
20 PBL103 & 85-95 & 66.35 & 84.55 \({}^{\ast}\) & 9.11 & 14.37 \({}^{\ast}\) & Semi-round & 4.62 \({}^{\ast}\) & 71 \({}^{\ast}\) & Purple & 6.39 & 992.2 \\ \hline \multicolumn{10}{c}{Green broccoli} \\ \hline SN80 & 70-75 & 79.45 & 79.3 & 7.03 & 12.25 & Round & 4.34 & 1.5 & Light green & 3.24 & 450.2 \\ LF02 & 85-90 & 70.7 & 67.01 & 10.72 & 15.9 & Round & 5.1 & 12 & Green-purple & 7.32 & 600.0 \\
20 CBL47 & 70-80 & 70.67 & 68 & 9.56 & 14.5 \({}^{\ast}\) & Round & 5.14 & 1.3 \({}^{\ast}\) & Green & 6.02 & 600.4 \\
20 CBL128 & 75-85 & 76.3 & 73.32 \({}^{\ast}\) & 9.74 & 15.35 & Round & 4.9 & 1.7 \({}^{\ast}\) & Dark green & 4.65 \({}^{\ast}\) & 571.0 \\ \hline \multicolumn{10}{c}{\({}^{\ast}\) indicates BC73 lines with LF02 showing a significant difference (\(\phi<0.05\)), \({}^{\ast}\) indicates BC73 lines with LF02 showing a highly significant difference (\(\phi<0.03\)).} \\ \end{tabular}
\end{table}