Callus formation from protoplasts of cell suspension cultures of Rosa 'Paul's Scarlet'

Sustained divisions of protoplast-derived cells obtained from cell suspension cultures of Rosa‘Paul's Scarlet’ leading to colony and callus formation was achieved. The rather low plating efficiencies observed for agar-plated protoplasts were partly due to early arrests in further development of dividing protoplast-derived cells and cell clusters. Successful cultivation of dividing protoplast-derived cells was particularly dependent upon frequent subculturing of the precultures and on an efficient procedure for viable protoplast isolation. Colony formation was largely independent of medium composition.