Growth and yield responses of west indian lemongrass (Cymbopogon citratus) to bio-inoculants under field conditions

Abstract

The efficacy of commercial microbial treatment on plant growth, nutrient uptake and yield is very well recognized for medicinal plants grown in field conditions. However, the use of commercial and native microbes for Cymbopogon citratus has rarely been exploited under field conditions. Therefore, in the present study we evaluated the efficacy of single and native arbuscular mycorrhizal fungal species (AMF) to mixture of mycorrhizal fungal species plus commercial plant growth promoting bacteria (PGPR) on morphological, biochemical and traits of mycorrhizal fungi associated with C. citratus. Two native AMF species, i.e. Glomus mosseae (G) and Acaulospora laevis (A), and Pseudomonas fluorescens (P) as commercial PGPR were used in this study. Three different treatments composition of selected microbes, i.e. G, G+P, and G+A+P, were utilized along control for crop production under open field conditions in a randomized complete block design. The plantlets were grown without external application of synthetic fertilizers. The results showed that the mixture of AMF and PGPR significantly increased the survival, biomass, P content of shoot as well as root, essential oil yield, and in vitro antibacterial potential of C. citratus against Escherichia coli and Staphylococcus aureus. In general, this study provides useful insight into the mixture AMF and PGPR treatment that can be applied to improve not only the biomass, phosphorus content, antibacterial potential, and yield attributes of C. citratus under open field conditions but also to improve AMF diversity in rhizosphere soil.