Standardization of in vitro mass multiplication protocol for hybrid tea rose cv. Grand Gala

An efficient protocol for in vitro multiplication of hybrid tea rose cv. Grand Gala was developed using axillary bud segments.Out of different pre-treatments of explants tried, the highest explant survival (82.16%) was obtained with carbendazim (0.2%) + diathane M-45 (0.2%) + 8-HQC (200 mg/l) for 4 h on a horizontal shaker (120 rpm). Sucrose concentration of 40 g/l in the medium seems to be optimal for in vitro shoot multiplication. Murashige and Skoog medium supplemented with 5.0 mg/l BAP + 0.2 mg/l NAA + 0.5 mg/l GA₃ was found most effective for culture establishment and shoot proliferation with highest number of micro-shoots (6.49 shoots/explant). Rooting of micro-shoots was induced on half-strength MS basal medium supplemented with NAA (0.5 mg/l) + IBA (0.5 mg/l). The regenerated plantlets were efficiently hardened in glass jars filled with vermiculite + agropeat (1:2) moistened with half-strength MS medium salts and covered with polypropylene lids, thereafter plants were successfully transferred to the glasshouse with good survival.