000			03820nam a22002177a 4500
003			OSt
005			20241202154226.0
008			130822b xxu||||| |||| 00| 0 eng d
040			_cCPGS
082			_a631.42
100			_aYumnam Bijilaxmi Devi _91187
245			_aMolecular characterization and screening of phosphate solubilising bacteria in acidic soils / _cby Yumnam Bijilaxmi Devi
260			_aUmiam : _bCPGS, CAU _cc2012
300			_a[32], 95p.: _bill.some col.;
440			_a[Soil Science and Agricultural Chemistry, School of Natural Resource Management] _91188
520			_aPhosphorus (P) limitation in terrestrial ecosystems may be widespread. More than 81% soils of 26.22 million hectare in North East India are acidic and P deficient, which more often limits the crop productivity. A large portion (50-92%) of water soluble fractions of applied P losses either by runoff water or gets fixed as Fe and Al complexes in these soils. So, rhizosphere-based P management may be an effective approach to improve P-use efficiency and crop yield through exploitation of biological potential for efficient mobilization and acquisition of P by crops, and reducing the overreliance on application of chemical fertilizer P. With this background this present study assessed whether the incidence of phosphorus-solubilising bacteria (PSB) and their ability to solubilise insoluble phosphates vary among diverse rice fields of the northeastern hill states of India. Further PSB isolates were screened for multifaceted plant growth promoting traits and their ability to stimulate yield and P-uptake of rice (var. Shahsarang). Altogether 173 PSB isolates were obtained in Ca3(PO4)2 amended Pikovskaya’s agar and the ability of these isolates to dissolve Ca3(PO4)2 ranged from 0.2 to 1.2 µg Pi ml-1 h-1. Out of 173 isolates, 43.28% and 12.5% isolates dissolved Na-phytate (ranged from 0.1 to 0.68 g Pi ml-1 h-1) and FePO4 (ranged from 0.05 to 0.2 (g Pi ml-1 h-1), respectively. Among 60 selected PSB isolates, 40%, 83.3%, 100% and 68.3% isolates were positive for production of IAA like substances (0.52 to 17.4 g ml-1 h-1), N2-fixation in nitrogen free bromothymol broth, phosphatase activity (0.16 to 3.24 g PNP ml-1 h-1) in Na-phytate amended minimal broth and cellulase activity in terms of zone of solubilisation on carboxy-methyl -cellulose agar (1.0 to 16.0 mm), respectively. In anacidic inceptisols application of PSB isolates and rock phosphate (@ 30 kg P ha-1) stimulated rice grain yield and P-uptake in grain to the extent at par with that of application of single super phosphate (@ 60 kg P ha-1). The PSB isolates showed higher ability to solubilise FePO4 and Na-phytate stimulated rice grain yield and P-uptake to a greater extent. The 16S rRNA gene sequence based identity of 21 selected PSB isolates revealed that PSB isolates belonged to genera Enterobacter, Pseudomonas, Klebsiella, Cedecea, Arthrobacter, Burkholderia, Serratia, Bacillus, Chromobacterium and Ralstonia,. The most abundant genus was Enterobacter. In conclusion, acidic soils of North East India harbour potential phosphate solubilising bacteria and these bacteria possess multiple plant growth promoting traits. In this study, at least PSB isolates MZS4-017, ARS1-002 and RBS1-006 were found to be superior strains in terms of stimulating rice growth, yield and P-uptake. These strains are potential candidates for inclusion in integrated nutrient management, organic farming and compost enrichment programmes for improving P-use efficiency after validation through multi- locational field trials.
650			_aMolecular characterization-Acidic soils _91189
650			_aPhosphate solubilising bacteria-Acidic soils _91190
700			_aDwipendra Thakuria _eMajor Advisor _91191
942			_2ddc _cTH
999			_c4093 _d4093