Mohit Kumar Singh, Manish Kumar Singh, Dinesh Kumar Meena, Prosanta Hazarika and Vishwanath Sharma
Abstract
Anthoshorea assamica (syn. Shorea assamica subsp. Assamica) is a critically endangered timber species of North-East India listed in IUCN Red List of Threatened Species. It belongs to the family Dipterocarpaceae and commonly known as Makei. The population of Makei is declining rapidly due to the recalcitrant nature of seed with short viability (5-7 days only), poor seed setting and quality, insect-pest attack in between the premature and mature stages. Multiplication and propagation of Makei mainly occur through seeds, as the seeds germinate easily but there is a prone threat to its existence due to low seedling survival rates. This study revealed the combined impact of Plant Growth-Promoting Rhizobacteria (PGPR) and Arbuscular Mycorrhizal Fungi (AMF) on seedling survival percentage and growth parameters of A. assamica. The rhizospheric soil of A. assamica was collected from Dilli Reserve Forest, Sivsagar Forest Division, isolated and identified 4 types of PGPR strains (Bacillus safensis, Bacillus subtilis, Staphylococcus hominis, and Bacillus wiedmannii) along with 3 types of AM spores (Glomus 75.60%, followed by Gigaspora 21.95% and Acaulospora 2.45%). A pot culture experiment was conducted in ICFRE- RFRI nursery, design used was CRD under semi controlled conditions having 9 treatments, 3 replications and 7 replicates per replication, a total of 189 seedlings used in the experiment. The result revealed that the combined effect of PGPRs and AM fungi (T8) showed significantly higher survival percentages (76.19%) in comparison to T0 (9.52%) and seedling growth in comparison to the other treatments. The T8 came out with best leaf length of 2.96 cm, leaf width of 2.23 cm, approx 3 leaves per seedlings, shoot length of 14.05 cm and collar diameter of 2.27 mm per seedlings. The results also revealed that synergistic effect of PGPRs and AM spores enhanced the nutrient solubilization, root expansion and led to healthier seedlings. This study showed that combining native microbes is the best and eco-friendly way to restore the critically endangered timber species, Anthoshorea assamica in NE India.