Optimization of In-vitro Callus Induction and Cell Suspension Cultures of Gyrinops walla for Commercialization

Gyrinops walla (G.walla), often referred to as ‘Walla Patta’ in Sinhala, is an indigenous, economically important plant renowned for its production of agarwood, which is a highly valuable resin having high economical, religious and traditional values. G. walla trees take 5-7 years on average to grow naturally before being inoculated to produce resin. In-vitro callus culture approach will shorten the agarwood resin production process significantly and be important for the industry. However, tissue culture methods are challenging due to explant contamination and low rate of callus production. Therefore, this study aims to optimize the conditions for surface sterilization and enhance in-vitro callus induction from leaf explants, with the objective of advancing the development of cell suspension cultures for commercialization. The experiment for surface sterilization and callus induction was conducted using leaf explants obtained from two G.walla mother plants, a home garden plant and a wild plant. The results suggested that 100 mg/L silver nitrate (AgNO3) and Dettol provide a better surface sterilization for callus production, especially in explants from a home garden mother plant exhibiting a low contamination rate (31%) compared to explants from wild plants (80%). Also, explants from home garden mother plant possessed better callus inducti on (65%) compared to explants from wild mother plants (13%). Furthermore, this study suggests that AgNO3 can be used as an alternative for hazardous chemicals such as mercuric chloride (HgCl2), which is commonly applied in surface sterilization and, introducing ground callus to suspension cultures will yield an improved callus proliferation in suspension cultures. Keywords: G.walla; In-vitro callus induction; cell suspension cultures; AgNO3; commercial use