Fertilizer adaptive bacteria Acidovorax valerianellae and Sinorhizobium fredii in integrated nutrient management of pigeon pea (Cajanus cajan L.)

Abstract

Plant growth-promoting (Indole acetic acid producing, phosphate solubilizing and siderophore producing) and chemical fertilizer adaptive variants of endophyte Acidovorax valerianellae CCR1 (JQ424873) with cross nodulating Sinorhizobium fredii SSR1 (JQ424873) were blended with a half dose of fertilizers for integrated nutrient management (INM) to enhance the productivity of pigeon pea (Cajanus cajan). Plant attributes showed enhancement in the growth of pigeon pea when used with lower concentration of urea, diammonium phosphate (DAP), muriate of potash (MOP) and gypsum, termed as inducer doses determined by sub-lethal concentration (LC50). Plant parameters described as early and late phase of growth (days after sowing; DAS) were enhanced significantly as compared to control and found to be statistically significant. The enhanced plant growth and yield parameters revealed integrated effect of SSR1 and CCR1 when blended with a half dose of chemical fertilizers. The recommended dose of chemical fertilizers attained about 20% increase in yield over control whereas, blend of SSR1 and CCR1 reduced (half) dose of chemical fertilizers enhanced the average yield of the plant by 49–40% over the control. Thus, it is propounded that the increase in the pigeon pea production with the use of fertilizer adaptive endophyte and rhizobia was highly positive. The chemotaxis phenomenon proved both the bacteria as a voracious root colonizer, thereby improving the plant growth directly, hence, these were redefined as fertilizer adaptive bacteria (FAB).