Growth hormones as a selection tool for somatic hybridization in Petunia

The growth hormones 6-benzylaminopurine (BAP), naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxy-acetic acid (2,4-D) were used as a selection tool in some protoplast fusion experiments involving different inbred lines of Petunia. The efficiency of the selection scheme, the possibility of cross-feeding, and the reaction of the tissue to 2,4-D at different development stages are described. The selection scheme was proved highly efficient in experiments carried out by Izhar et al., Mol. Gen. Genet., 190 (1983) 468 and S. Izhar (unpublished), with only a negligible amount of cross-feeding between protoplasts of different lines. Lines sensitive to 2,4-D sprays require 2,4-D for protoplast division and tissue development to callus, while the lines resistant to 2,4-D sprays were not able to use 2,4-D for protoplast division and development.