Quality Stock Production of Aquilaria malaccensis Lamk. Using Arbuscular Mycorrhizal Inoculation: Restoration of Agarwood Source

Aquilaria malaccensis Lamk. is a critically endangered and economically important forest tree species of North-east India. In the current study, a biotization experiment was performed to show the effect of arbuscular mycorrhizae on obtaining high-quality agarwood-producing plants. One-month-old seedlings were inoculated in a designed experiment with single and combined endomycorrhizal treatments. All inoculated seedlings showed significant biomass production than control seedlings. The Biovolume index (Bi) was higher in all inoculated plant seedlings than in non-inoculated control seedlings but Acaulospora spp. (EM2) treatment had a higher Bi (78.17±0.024) than the rest of the inoculation treatments. The Quality index (Qi) value was also high (1.22±0.024) in EM2 treatment followed by the Glomus spp. + Acaulospora spp. (EM1+EM2) treatment (1.10±0.031) and Glomus spp. (EM1) (0.83±0.014) treatment. Control seedlings had a lower value (0.14±0.021) of Qi than the rest of the treatments. The plastochrone interval index (Pi) of A. malaccensis after 60 days of inoculation was low in EM1+EM2 treatment as the time interval for initiation of 2nd leaf was 1 day than rest of the treatments in which the time interval was 4 days for initiation of the 2nd leaf primordia. Substantially, the leaf primordia appearance in the EM1+EM2 treatment was impetuous than rest of the treatments. In the control treatment, the 8th leaf primordia appeared on the 36th day and after that, there was no appearance of leaf primordia. Therefore, the EM2 treatment was the best single/alone treatment of mycorrhizal inoculation followed by EM1+EM2 synergistic treatment for quality stock production of A. malaccensis seedlings.