Field evaluation of multistrain biofertilizer for improving the productivity of different mungbean genotypes

Mungbean can successfully be grown in the small slots present in the existing cropping systems that may increase the farmer income and can also restore soil fertility. The inoculation of crop plants with bacterial inoculants has the potential to increase crop productivity even under different soil and climatic conditions. A field experiment was conducted to evaluate the effectiveness of multi-strain biofertilizer prepared through combined use of Rhizobium phaseoli and Pseudomonas fluorescens and Bacillus subtilis for enhancing the growth, nodulation and productivity of ten mungbean genotypes under field conditions, and effect of inoculation on total bacterial DNA (population) in soil. The experiment was laid out in randomized complete block design (RCBD) with factorial arrangements and three replications. Results revealed that inoculation with multistrain biofertilizer increased the nodule numbers, growth, and yield under different mungbean genotypes when compared with their respective uninoculated control. The genotypes showed different productive potentials either with or without inoculation under field conditions. The genotype NCM 2015 yielded more but inoculation was more effective with genotypes NM 17, NM 19 and NCM-252-10 under field conditions of Bahawalpur. Results of 16S rRNA analysis showed a higher number of gene copies in the rhizosphere of inoculated plants of all mungbean genotypes than those of uninoculated plants. Maximum total bacterial population was observed in the rhizosphere of inoculated plants in NM 11 that was significantly better than un-inoculated control plants of the same mungbean line but non-significant when compared with other lines under inoculation. It is concluded that the use of multistrain biofertilizer prepared through combined use of Rhizobium and PGPR strains containing ACC-deaminase could be an effective approach to improve growth, nodulation and yield of mungbean genotypes. The response of different genotypes to the inoculation varied significantly. So, research for the development of inoculum for different advanced genotypes should be continued and more emphasis should be deployed to develop biofertilizers with efficient strains to use them under different climate and soil conditions.