a protocol for mass production of rosa hybrida cv. iceberg through in vitro propagation

interactive effect of plant growth regulators6-benzylaminopurine (bap) (0, 2, 4 and 8 µm) and1-naphtalene acetic acid (naa) (0, 0.05, 0.25 and 0.5µm) in van der salm (vs) medium was used to optimize in vitro propagation of rosa hybrida cv. iceberg.shoot proliferation and number of new leaves weremeasured as growth indicators. as the concentrationof bap was raised, growth rate increased with all ofthe above naa concentrations. however, the highestnumber of axillary shoots and new leaves were produced with 4 µm bap, which was considered the optimal level. a multiplication rate of 10 folds with a maximum number of axillary shoots (10.1) and new leavesper explant (25) were obtained in the medium containing 4 µm bap plus 0.5 µm naa. in vitro-derived shootswere used to investigate root initiation and growth bylowering the concentration of vs mineral salts andvitamins. three strengths of vs (full, 1/2 and 1/4) werecompared in semi-solid and liquid medium. the average number of roots (4.35) and root length (0.82 cm)were significantly higher in 1/4 strength vs. the highest percentage of rooting (93.33%) and number ofroots (4.45) were significantly higher in semi-solid thanliquid medium. the regenerated plantlets were successfully transferred to soil and the survival rates ofthe rooted plantlets transferred to soil were 70% and90% in plants treated with semi-sold and liquid media,respectively