The utilization of plant growth-promoting bacteria to enhance stevia ( Stevia rebaudiana) herb yield at low land

Abstract

Stevia is a native crop of sub-tropical regions; its cultivation is extended to low land tropical regions, which might the growth is not good as in its origin growth areas. Bacteria as growth promoters are expected to enhance stevia growth in low-land tropical regions. This study aimed to determine the effect of bacteria on the growth and yield of stevia. The research was conducted at the Microbiology Laboratory and Greenhouse of the Indonesian Spices and Medicinal Crops Research Institute at 240 m above sea level and was arranged in a complete randomized block design with four replications. The treatments consisted of 1) control, 2) rhizosphere bacteria Brevibacillus parabrevis GF13, 3) endophytic bacteria Mesorhizobium soli NHI-8, 4) endophytic bacteria Bacillus pacificus EB422, 5) a combination B. parabrevis GF13 + M. soli NHI-8, and 6) a combination of Br. parabrevis GF13 + B. pacificus EB422. The highest increase in total production of fresh (32.8%) and dry (25.86%) herbs were found in treatment 4 (endophytic bacteria Bacillus pacificus EB422). The treatment caused the plant to have the highest nutrient uptake 0.124 N g/plant, 0.051 P2O5 g/plant, and 0.172 K2O g/plant. The treatment increased soil chemical properties.