effect of agar and different culture media on the micropropagation of rosa hybrida cv.’black baccara’

in vitro propagation of plant has played a very important role in rapidmultiplication of cultivars with desirable traits and production of healthy and disease-free plants. in the present investigation, the objectives were to optimize the micropropagation of rose hybrid ‘black baccarat’ cultivar. in proliferation step, the nodal segments (1.5 cm) was cultured on both liquid and solid media (ms, vs and wpm). the results showed that the highest shoot proliferation was obtained on vs medium. the highest amount of multiplication and the growth rate were obtained in the liquid medium. for rooting, three concentrations of vs mineral salts (full-, half-, and quarter-strength) containing naa (0.5 μm) were tested in semi-solid and liquid media. root initiation influenced by mineral concentration in the medium. the investigation showed that the highest number of roots was observed in semi-solid 1/4 vs medium. variation in multiplication and growth rate of explants can be explained on the basis of water potential and mineral availability to the explants in the liquid medium.