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Subject: Microbiology × Author: Gouri, Vinita × End date: 2017 × Start date: 2010 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Growth promotory effect of drought tolerant bacteria on wheat crop under drought stress
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2017-07) Gouri, Vinita; Singh, Ajay Veer
    In natural environmental condition plants continuously exposed to various biotic and abiotic factors. Drought is considered as major abiotic stress and adversely affects plant growth and productivity worldwide. Plants under drought stress conditions show reduced root length, shoot length, deficiency of nutrients and increases disease susceptibility and hence decreases economic yield of crop. In this context, present study was carried out with the application of drought tolerant plant growth promoting rhizobacteria (PGPR) in wheat to promote growth and productivity under drought stress conditions. During study, total sixty bacterial isolates were retrieved and revived from departmental culture collection. On the basis of growth present on tryptic soy broth medium supplemented with 6% poly ethylene glycol and 20% NaCl, fourteen bacterial isolates were selected as drought tolerant. These drought tolerant bacterial isolates were further checked for plant growth promoting activities such as siderophore production, zinc solubilization, phosphate solubilization and ACC deaminase activity and ten best potential bacterial isolates were screened for further study. Afterward, screened potential bacterial isolates were selected and characterized on the basis of cell and colony morphology, biochemical characteristics and carbohydrate utilization tests. Now these potential isolates were characterized functionally and tested for plant growth promoting traits such as exopolysaccaride production, ammonia production, indole acetic acid production and hydrogen cyanide production. Furthermore, potential bacterial isolates were evaluated for antibiosis activity against two pathogenic fungi of wheat, four isolates were able to suppress mycelial growth of Fusarium oxysporum and three bacterial isolates were able to suppress mycelial growth of Alternaria spp. However, SRPII7 isolate was effective against both the fungi. Furthermore, an in situ greenhouse pot experiment was designed under drought stress with all ten drought tolerant plant growth promoting isolates with early variety of wheat (Triticum aestivum var. UP-2785). Results of green house pot experiment confirmed that all bacterial isolates were significantly able to improve plant growth and productivity in terms of agronomical parameters such as root length, shoot length, dry weight of plant, spike length, number of grains/spike, 1000 grains weight and % harvest index, while four bacterial isolates i.e. WRPA13, WRPA26, SRA1 and SRK14 prove more potential compare to all other isolates and helps wheat plant to cope up with drought stresses. In vitro and in situ studies depicted the potentiality of four bacterial isolates for their promising plant growth promoting activity under drought stress. In respect to said results, present study concluded that these four potential bacterial isolates i.e. WRPA13, WRPA26, SRA1 and SRK14 can be employed as bioinoculant/biofertilizer to improve drought tolerance and nutrient enhancement in wheat crop for sustainable agriculture.