TcBBM expression throughout the process of primary and secondary embryogenesis. A. Schematic of the process of either primary (top) or secondary somatic (bottom) embryogenesis. PCG = Primary Callus Growth media, SCG = Secondary Callus Growth media, ED = Embryo Development media. B. TcBBM expression throughout primary somatic embryogenesis. C. TcBBM expression throughout secondary somatic embryogenesis (* represents a p-value < 0.05 for the Student’s t-test). D. TcBBM expression in embryonic (EC) and non-embryonic calli (Non-EC) obtained from secondary SE calli. Non-embryonic calli were classified as undifferentiated calli tissue that had not produced visible embryos up to the date the tissue was harvested. Embryogenic calli is also undifferentiated tissue; however, it is harvested from explants that had produced visible embryos. Expression levels for panels B, C and D were analyzed by RT-qPCR and the TcBBM gene normalized relative to that of TcACP1 and TcβTub genes.