Cooperative interaction of Glomus intraradices with plant growth-promoting rhizobacteria promotes plant development and essential oil yield of Pogostemon cablin and reduces disease occurrence under organic field conditions

In this study, two efficient plant growth promoters coupled with potent antagonists viz. Pseudomonas monteilii strain-CRC1, Cedecea davisae strain-CRC2 and AM Fungi named Glomus intraradices (GI) were assessed individually and in combination for their potential to increase yield and essential oil yield as well as lessen the severity of the disease caused by Rhizoctonia solani in Pogostemon cablin (patchouli). In field trials, nine treatments were used: CRC1, CRC2, GI, CRC1 + CRC2, CRC1 + GI, CRC2 + GI, CRC1 + CRC2 + GI, un-inoculated vermicompost, and uninoculated soil as control, with five replications in randomised complete block design, where Rhizoctonia root-rot/wilt was a persistent problem. As compared to the control, the plants inoculated with CRC1 + CRC2 + GI performed best and significantly increased the plant height (87%), plant spread (50%), branch count (67%), herbs yield (67%), essential oil yield (69%) as well as reduced the percent disease index (68%) and percent wilt incidence (87.5%). Moreover, the Patchouli alcohol, a key component of its essential oil, was found to be markedly enhanced by 10% in CRC1 + CRC2 + GI inoculated plants. Furthermore, 43, 27 and 191% of higher uptake of NPK were observed in CRC1 + CRC2 + GI inoculated plants, respectively. After harvesting, a considerable abundance of CRC1, CRC2, and GI in the rhizosphere soil was observed. The results of this experiment indicate that higher herb yields and other observed plant attributes could be due to improved nutrient (NPK) uptake by the patchouli plants. The management of wilt disease and the production of high-quality essential oils in patchouli both can be accomplished with the help of the established consortium.