Vol:.(1234567890) J Plant Growth Regul (2017) 36:608–617 DOI 10.1007/s00344-016-9663-5 1 3 Co-inoculation with Enterobacter and Rhizobacteria on Yield and Nutrient Uptake by Wheat (Triticum aestivum L.) in the Alluvial Soil Under Indo-Gangetic Plain of India Ashok Kumar 1,2  · B. R. Maurya 1  · R. Raghuwanshi 2  · Vijay Singh Meena 1,3  · M. Tofazzal Islam 4   Received: 2 August 2016 / Accepted: 9 November 2016 / Published online: 17 January 2017 © Springer Science+Business Media New York 2017 production of organic acids, however, Enterobacter sp. was inactive. The efects of these three rhizobacteria were eval- uated on wheat in alluvial soils of the Indo-Gangetic Plain by inoculation of plants with bacterial isolates either alone or in combinations in both pot and ield conditions for two successive years. Rhizobacterial inoculation either alone or in consortium of varying combinations signiicantly (P ≤ 0.05) increased growth and yield of wheat compared to mock inoculated controls. A consortium of two or three rhizobacterial isolates also signiicantly increased plant height, straw yield, grain yield, and test weight of wheat in both pot and ield trials compared to single application of any of these isolates. Among the rhizobacterial treatment, co-inoculation of three rhizobacteria (Enterobacter, M. arborescens and S. marcescens) performed best in promo- tion of growth, yield, and nutrient (N, P, Cu, Zn, Mn, and Fe) uptake by wheat. Taken together, our results suggest that co-inoculation of Enterobacter with S. marcescens and M. arborescens could be used for preparation of an efec- tive formulation of PGP consortium for eco-friendly and sustainable production of wheat. Keywords Plant health · PGPR · P-solubilization · PGP activities · Crop productivity Introduction During the green revolution, high-yielding varieties with application of synthetic fertilizers and pesticides were introduced for increasing yields of crops. Indiscrimi- nate use of hazardous synthetic fertilizers and pesticides caused environmental pollution and deteriorated soil health (Elkoca and others 2010). Moreover, production of crops largely depending on synthetic chemicals also decreased Abstract The aim of this work was to evaluate the efects of co-inoculation with phosphate-solubilizing and nitrogen- ixing rhizobacteria on growth promotion, yield, and nutri- ent uptake by wheat. Out of twenty-ive bacteria isolated from the rhizosphere soils of cereal, vegetable, and agro- forestry plants in eastern Uttar Pradesh, three superior most plant growth-promoting (PGP) isolates were characterized as Serratia marcescens, Microbacterium arborescens, and Enterobacter sp. based on their biochemical and 16S rDNA gene sequencing data and selected them for evaluating their PGP efects on growth and yield of wheat. Among them, Enterobacter sp. and M. arborescens ixed signiicantly higher amounts (9.32 ± 0.57 and 8.89 ± 0.58 mg Ng −1 car- bon oxidized, respectively) of atmospheric nitrogen and produced higher amounts (27.06 ± 1.70 and 26.82 ± 1.63 TP 100 µg mL −1 , respectively) of IAA in vitro compared to S. marcescens (8.32 ± 0.39 mg Ng −1 carbon oxidized and 21.29 ± 0.99 TP 100 µg mL −1 ). Although both M. arbore- scens and S. marcescens solubilized remarkable amounts of phosphate from tricalcium phosphate likely through * Ashok Kumar ashokbhu2010@gmail.com; ashokabt@gmail.com * Vijay Singh Meena vijay.meena@icar.gov.in; vijayssac.bhu@gmail.com 1 Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India 2 Department of Botany, MMV, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India 3 ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan, Almora, Uttarakhand 263601, India 4 Department of Biotechnology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh