Effect of promising rhizobia and plant growth promoting rhizobacteria on soybean (Glycine max L. Merrill) under water stress condition
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Date
2019-07
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The investigation was carried during 2018-2019 to study the effect of promising rhizobia and plant growth promoting rhizobacteria on soybean (Glycine max L. Merrill) under water stress condition. Pot experiment was conducted during kharif season of the year 2018 at Norman E.
Borlaug Crop Research Centre, G. B. Pant University of Agriculture and Technology, Pantnagar. The experiment comprised sixteen treatment combinations having different rhizobial and plant growth promoting rhizobacterial isolates, with and without water stress at R5 stage which were replicated three times in completely randomized block design. The experiment soil was silty clay loam. Inoculation with PGPR isolate Pant 6, across the moisture regimes, supported the highest shoot length (122.67 cm) at R5 stage. Whereas under moisture stress condition dual inoculation with B. lianigense + Pant 6 produced the higher shoot length. Dual inoculation of B. dequigense + Pant 6 resulted in highest root length (79.00 cm) at R5 stage under moisture stress condition. Inoculation with B. lianigense supported the highest number of nodules (124 plant-1) under moisture stress condition. Overall dual inoculation with B. lianigense + Pant 6 (PGPR) resulted highest root volume (54.67 cm3 plant-1) at R5 stage similar result were obtained under moisture stress condition. Inoculation with B. lianigense +Pant 6 (PGPR) supported highest number of trifoliate leaves (40.22 plant -1) under moisture stress condition. Highest shoot dry weight was recorded with B. lianigense under moisture stress condition at R5 stage as well as at harvest. B. lianigense supported the highest dry root biomass under normal as well as moisture stress condition. B. dequigense + Pant 6 supported highest leaf chlorophyll ‘a’ in leaves (16.43 mg g-1) whereas under moisture stress Pant 2 + Pant 6 supported highest chlorophyll ‘b’ in leaves. Under normal as well as moisture stress conditions highest leaf relative water content was recorded with dual inoculation of Pant 2 + Pant 6. Under moisture stress Pant 6 (PGPR) recorded the highest leaf proline content(0.54%).Under moisture stress condition highest grain yield (10.40 g plant-1) was recorded with inoculation of B. dequigense + Pant 6 followed by with B.lianigense. It can be deduced from the study that inoculation with Bradyrhizobium lianigense, B. dequigense and Pant 6 (PGPR) under both the water regimes enhanced RWC in leaves, leaf area, chlorophyll content, dry biomass production and nutrient concentration and their uptake and yield. Under moisture stress microbial inoculants increased the proline content in leaves over uninoculated control. The results of the study indicate the potential of the promising rhizobial isolates alone or together with PGPR to mitigate the temporary moisture stress of 8-10 days in soybean.