Abstract:
A study was conducted to explore the efficacy of different Fusarium strains in inducing resin production in
Gyrinops walla and to optimize conditions for in vitro mass cultivation of the selected fungal strains. Four
Fusarium strains isolated from infected plant tissues were used for the screening. Mycelial suspensions
(separately or mixed) prepared in 20% and 30% coconut and toddy palm treacle were injected through
the drilled holes of two year old G. walla stems (girth 32 cm2). Two months after inoculation,
characteristic stem lesions were observed with all the tested strains that indicated successful induction of
the defense response leading to agarwood production. All the treatments produced the necrotic streaks
along the stem, starting from the inoculation point whereas; the control treatment did not produce such
streaks. To identify the optimum conditions for in-vitro fungal growth, the fungal cultures on potato
dextrose agar (PDA) were subjected to three light levels (total dark, 12 h light/dark, and total light) and
three incubation temperatures (25 °C, 28°C, 32°C).Results revealed that the fungal growth was optimum at
25°C and at 12 dark/light incubation (P<0.05). Among three different liquid media (potato broth, chickpea
broth and soybean broth) tested for the mass culture of Fusarium strains, chickpea broth resulted the
highest fresh weight and dry weight of mycelia (P<0.05). The study concludes that Fusarium spp. can
successfully used to artificially induce resin production in G. walla and the inoculums can be conveniently
produced in large scale under the given laboratory conditions.
