Optimization of in vitro sterilization protocol for Hydrangea (Hydrangea macrophylla Thumb. Ser)

Hydrangea, a widely used ornamental plant in landscaping, is routinely featured but has recently gained popularity as a potted plant and for use in both fresh and dried cut flower products. The research established an appropriate sterilization method for six distinct types of plant explants. The pretreatment consisted of Carbendazim and Mancozeb fungicides applied alone and in combination with various concentrations and timings to evaluate their performance in front of surface sterilization treatments with 0.1 % HgCl2 and 0.5 % NaOCl utilized at different exposure durations and concentrations. The combined fungicide treatment of explants with 0.2 % for 30 min followed by HgCl₂ and NaOCl sterilization proved effective at controlling both fungal (11.67 %), bacterial (1.67 %) infection, total contamination levels (13.33 %) and achieved the highest survival percentage increase (86.67 %). Surface sterilization with HgCl2 for 6 min followed by NaOCl at 2 min applied to H. macrophylla nodes and internodes and shoot tip explants led to the highest survival (85.54 %) while generating cultures with minimal overall contamination (3.97 % bacterial and 96.03 % aseptic), accompanied by low mortality (10.49 %). The combination of HgCl2 for 5 min with NaOCl for 2 min produced the most aseptic leaf cultures (85.10 %) with (68.33 %) leaf explant survival while minimizing total infections (15.00 %) between microorganisms.