Growth promotion and yield attribute improvement of five groundnut (Arachis hypogaea L.) varieties by the application of plant growth promoting rhizobacteria

Abstract

The aim of this investigation was to evaluate the symbiotic performance of a collection of ten plant growth-promoting rhizobacteria (PGPR) strains on the growth and yield attributes of five groundnut varieties. The screening was conducted in the greenhouse using seeds of the varieties Essamay, Amoul Morom, 55-437, Fleur 11 and Sunu Gaal grown in 1.5 kg pots with Sangalkam soils. Leaf chlorophyll content, plant height, number of branches, biomass production, number and mass of pods were the parameters evaluated in response to groundnut inoculation. Overall, the results highlighted the effectiveness of inoculation with certain PGPRs on the growth and yield parameters. However, the effects of the inoculants were highly dependent on the variety used and the parameter studied. In particular, the strains RF8, SI12, SR6, SI16, SI27 and SS10 were the most efficient in improving the plant growth and yield attributes of the varieties Essamay, Amoul Morom and Sunu Gaal. In contrast, Fleur 11 and 55-437 were less responsive in terms of yield attributes, demonstrating that the response to groundnut inoculation is variety dependent. In addition, a significant increase in the estimated leaf chlorophyll content was only observed in Fleur 11 and Sunu Gaal, which was not expected and could be attributed to a lower N 2 fixation capacity of the indigenous rhizobia. Nevertheless, the increases in growth and yield parameters obtained in this study can be considered as a promising data for the use of bacterial biofertilisers in groundnut cultivation.