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Certain members of Genera Aquilaria, Gyrinops, Gonystylus and Aetoxylon of
Thymelaeaceae family produce a highly valuable resin inside the stem called
agarwood.lt is used for perfume manufacturing, burning aroma for cultural and religious
activities in many countries of the world. Gyrinops walla is the only agarwood
producing member present in Sri Lanka belongs to this family. Formation of
agarwoodin the tree stem isbelieve to be due to a defense mechanism against the causal
agents, either environmental stress or disease. Natural formation of agarwood is rare
and low in content. Therefore, the present study was aimed at identifying the best
artificial inoculation methods that can induce agarwood formation in G. walla. The
selected methods are practiced for Aquilaria species in Northeast Asian region covering
all types of inoculations.This study tested, chemical, mechanical and biological
methodsjinserting iron nails, galvanized tubes, polyvinyl chloride tubes and
polypropylenetubeswere used as mechanical method and sodium chloride and sodium
bi-carbonatewereused as chemicals. Forest mushroom myceliawasused as the biological
method to induce agarwood formation.Medium size G. walla tress grown in Kalawana
and Mathugama in the wet zone of Sri Lanka were selected to test these methods. Five
replicates were used for each treatment which were applied in spiral manner on the tree
stem. Agarwood formed tissues were extracted 12 months after the inoculation and
resins of these tissues were collected by solvent extraction. Colours of both resinous
tissues and extracted resins were determined using Munsell colour chat. Aroma
produced when burning the resinous tissues was detected by a sensory panel.
Significance of resin contents among different inoculation treatments were tested using
One-way ANOVA.According to the results, the highest mean resin content (4.38%) was
recorded from the trees inoculated with sodium chloride and the lowest mean was
recorded from the trees inoculated with forest mushroom mycelia (2.16%).One-way
ANOVA showed a significant difference of resin content between different artificial
methods. Colours of both resinous tissues and extracted resins varied from brown to
very dark brown. All treatments produced an aromatic agarwood scent which is unique
to G. wallawben burning wood samples. Finally, out of the selected methods, it was
revealed that addition of sodium chlorideisthe best method that can be used to induce
agarwood resin formation in G. walla.
