Vol. 12, Issue 12 (2023)

Author(s):
Supreetha BG, Prakasha DP, Kulapati Hipparagi, Prabhulinga G, Gurumurthy SB, Ratnakar Manjunath Shet and Ashok

Abstract:
Finger lime (Citrus australasica F. Muell) stands out among Australian citrus species, gaining attention for its unique finger-like fruits and the popular term "lime caviar" attributed to its juice vesicles. The rise in demand for finger lime has intensified the need for efficient tissue culture methods to propagate selected genotypes, free from contamination. This research focuses on establishing a robust surface sterilization protocol for in vitro culture initiation of finger lime. The study explores the impact of various exposure times of sodium hypochlorite (4%) on different explant types (leaf, internode, nodal segment, and shoot tip). Results indicate that a 10-minute exposure to sodium hypochlorite (NaOCl) (4%) is optimal for minimizing contamination and maximizing survival. Furthermore, the investigation extends to the combined effect of mercuric chloride (HgCl₂) with sodium hypochlorite (4%). To enhance the sterilization process, ethanol (70%) exposure times are introduced in combination with the best sodium hypochlorite and mercuric chloride treatments. The findings reveal that a 45-second ethanol treatment complements the sterilization process, achieving low contamination levels in nodal and shoot tip explants. However, a trade-off is observed with a decrease in survival rates due to the potentially lethal effects of higher concentrations and exposure times. The study provides valuable insights into the initiation of response, days required for shoot induction, and overall health of the explants. Nodal segments emerge as the most responsive explants, exhibiting 100% initiation of response across various treatments.