Optimization of sterilization techniques for Dendrocalamus asper nodal explants to improve viability and minimize contamination

Dendrocalamus asper is a valuable bamboo species known for its edible shoots and industrial applications, making its propagation highly desirable. Conventional methods are limited by low seed availability and slow growth, and in vitro propagation offers a promising alternative but is hindered by contamination, necessitating effective sterilization. Preliminary trials using common sterilization agents such as clorox and ethanol were ineffective in achieving satisfactory sterilization; hence, mercuric chloride (HgCl 2 ) was used to improve the results. This study optimised the protocols using HgCl 2 to achieve higher explant viability while minimizing contamination. Nodal explants were treated with various HgCl 2 concentrations (0.05%, 0.1% and 0.2%) for different durations (5, 10 and 15 minutes). The findings revealed that increased HgCl 2 concentrations and extended exposure times generally reduced the contamination rates but adversely affected explant viability. The lowest contamination rate (33.33%) was observed in 0.1% HgCl 2 at 15 minutes, whereas the highest rate occurred in 0.05% HgCl 2 at 5 minutes (76.92%). Explant viability, indicated by the successful emergence of bud breaks from sterile explants, was the highest (23.53%) in 0.05% HgCl 2 for 15 minutes, followed by 0.1% HgCl 2 for 5 minutes (21.43%). Overall, the treatment with 0.05% HgCl 2 for 15 minutes balanced between a relatively lower contamination rate (47.06%) and the highest viability percentage. The findings demonstrated that adjusting the HgCl 2 concentration and exposure time is critical for effective sterilization. Although the highest viability rate achieved was 23%, this protocol offers insights for improving sterilization efficiency while highlighting the need for further refinement to enhance explant viability.