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Subject: Microbiology × Author: Sharma, Kavia × End date: 2023 × Start date: 2020 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Evalution of Plant Growth Promoting Rhizobacteria As potemtial Biofertilizer For Broccoli ( Brassica Oleracea L.)
    (Punjab Agricultural University, Ludhiana, 2022) Sharma, Kavia; Jupinder Kaur
    The present study was carried out with the aim to develop a plant growth-promoting rhizobacterial inoculant for improving the growth and yield of broccoli. A total of 24 bacteria were isolated from rhizosphere of broccoli collected from the fields of Punjab Agricultural University, Ludhiana and village Sangrur, Mansa, Barnala and Patiala. Biochemical characterization of these rhizobacterial isolates showed that most of these were oxidase, urease, indole, MR and catalase positive and were involved in starch hydrolysis and gelatin liquefaction whereas negative for citrate and VP test. These isolates were screened for multifarious plant growth-promoting traits viz. solubilization of phosphate and zinc, production of IAA, siderophore, ammonia, HCN and growth on nitrogen free medium. Out of 24 isolates, 17 isolates showed solubilization of phosphate on modified Pikovskaya agar with solubilization index ranging from 0.5-4.5 cm and 53.63-178.6 μg/ml in liquid medium. Eleven isolates showed solubilization of zinc oxide (solubilization index: 0.4-1.9 cm), five isolates showed solubilization of zinc carbonate (solubilization index: 0.3-1.2 cm) and zinc phosphate (solubilization index: 0.1-2.5 cm). Siderophore production was exhibited by fourteen isolates (0.3-1.4 cm). All the isolates were positive for auxin (without tryptophan: 2.04- 13.90 μg/ml; with tryptophan: 10.05-32.04 μg/ml) and ammonia production as well as ammonia excretion (1.803.65 μg/ml). The luxuriant growth on different nitrogen free medium was observed for all the isolates and higher HCN production was observed in three bacterial isolates. Out of these 24 isolates, two potential bacterial isolates RP4 and RP5 (which were named as CBF 2) were selected on the basis of PGP traits for evaluation of their potential to promote growth and yield of broccoli under pot as well as under field conditions. In green house experiment, these isolates when used synergistically showed a significant improvement in soil enzymatic activities (viz. dehydrogenase: 26.13 µg TPF formed h-1 g-1 of soil, alkaline phosphatase: 14.02 µg PNP formed h-1 g -1 of soil and urease: 370.80 µg urea hydrolysed formed h-1g -1 of soil) and plant growth parameters (plant height: 45.7 cm, root length: 6.3 cm, stem diameter: 3.9 cm, fresh weight of shoot :167.85 g, dry weight of shoot:35.70 g, number of leaves per plant: 26, days taken to visible curd:56 days, head compactness: 1.36 cm, number of heads/plant: 4 heads, mean head weight: 87 g and floret stalk length: 12.8 cm) over the control as well as other bioinoculants. The field evaluation of these bacterial isolates as consortium along with FYM and inorganic fertilizers was carried out using Palam samridhi variety of broccoli. The combined application of bacterial strains (RP4 and RP5) and FYM resulted in significantly higher soil microbial population and enzyme activities. Significantly higher available nitrogen (137.30 kg ha-1), available phosphorus (34.21 kg ha-1) and available potassium (170.15 kg ha-1) were also observed in treatment having FYM and bacterial inoculants (N75FYM+N25 + CBF 2). Significantly higher plant nutrient uptake of nitrogen (98.87 kg ha-1), phosphorus (24.84 kg ha-1), potassium (182.27 kg ha-1) was observed in (N75FYM+N25+ CBF 2) and higher uptake of micronutrients viz. zinc (75.5 mg/kg), iron (172.16 mg/kg) and manganese content (71.11 mg/kg) were found to be significantly higher in treatment (N100FYM+ CBF 2) having synergistic application of organic and bio-fertilizers. The various growth attributes of broccoli viz. plant height: 42.1 cm, root length: 11 cm, stem diameter: 4.9 cm, fresh weight of shoot: 214.20 g, dry weight of shoot:38.18 g, number of leaves per plant: 29, days taken to visible curd:44 days, head compactness: 1.11 cm, head yield: 153.15 q/acre, number of heads/plant: 6 heads, mean head weight: 88 g and floret stalk length: 12.8 cm was observed to be statistically higher in treatment T10 with combined application of FYM and bacterial isolates (N100FYM+ CBF 2). The study has led to the selection of a plant growth-promoting bacterial consortium as a potential bacterial inoculant for improving the growth, yield and nutrient content in broccoli.
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    Evaluation of Plant Growth Promoting Rhizobacteria As Potential Biofertilizer For Broccoli ( (Brassica Oleracea L.)
    (Punjab Agricultural University, Ludhiana, 2022) Sharma, Kavia; Jupinder Kaur
    The present study was carried out with the aim to develop a plant growth-promoting rhizobacterial inoculant for improving the growth and yield of broccoli. A total of 24 bacteria were isolated from rhizosphere of broccoli collected from the fields of Punjab Agricultural University, Ludhiana and village Sangrur, Mansa, Barnala and Patiala. Biochemical characterization of these rhizobacterial isolates showed that most of these were oxidase, urease, indole, MR and catalase positive and were involved in starch hydrolysis and gelatin liquefaction whereas negative for citrate and VP test. These isolates were screened for multifarious plant growth-promoting traits viz. solubilization of phosphate and zinc, production of IAA, siderophore, ammonia, HCN and growth on nitrogen free medium. Out of 24 isolates, 17 isolates showed solubilization of phosphate on modified Pikovskaya agar with solubilization index ranging from 0.5-4.5 cm and 53.63-178.6 μg/ml in liquid medium. Eleven isolates showed solubilization of zinc oxide (solubilization index: 0.4-1.9 cm), five isolates showed solubilization of zinc carbonate (solubilization index: 0.3-1.2 cm) and zinc phosphate (solubilization index: 0.1-2.5 cm). Siderophore production was exhibited by fourteen isolates (0.3-1.4 cm). All the isolates were positive for auxin (without tryptophan: 2.04- 13.90 μg/ml; with tryptophan: 10.05-32.04 μg/ml) and ammonia production as well as ammonia excretion (1.803.65 μg/ml). The luxuriant growth on different nitrogen free medium was observed for all the isolates and higher HCN production was observed in three bacterial isolates. Out of these 24 isolates, two potential bacterial isolates RP4 and RP5 (which were named as CBF 2) were selected on the basis of PGP traits for evaluation of their potential to promote growth and yield of broccoli under pot as well as under field conditions. In green house experiment, these isolates when used synergistically showed a significant improvement in soil enzymatic activities (viz. dehydrogenase: 26.13 µg TPF formed h-1 g-1 of soil, alkaline phosphatase: 14.02 µg PNP formed h-1 g -1 of soil and urease: 370.80 µg urea hydrolysed formed h-1g -1 of soil) and plant growth parameters (plant height: 45.7 cm, root length: 6.3 cm, stem diameter: 3.9 cm, fresh weight of shoot :167.85 g, dry weight of shoot:35.70 g, number of leaves per plant: 26, days taken to visible curd:56 days, head compactness: 1.36 cm, number of heads/plant: 4 heads, mean head weight: 87 g and floret stalk length: 12.8 cm) over the control as well as other bioinoculants. The field evaluation of these bacterial isolates as consortium along with FYM and inorganic fertilizers was carried out using Palam samridhi variety of broccoli. The combined application of bacterial strains (RP4 and RP5) and FYM resulted in significantly higher soil microbial population and enzyme activities. Significantly higher available nitrogen (137.30 kg ha-1), available phosphorus (34.21 kg ha-1) and available potassium (170.15 kg ha-1) were also observed in treatment having FYM and bacterial inoculants (N75FYM+N25 + CBF 2). Significantly higher plant nutrient uptake of nitrogen (98.87 kg ha-1), phosphorus (24.84 kg ha-1), potassium (182.27 kg ha-1) was observed in (N75FYM+N25+ CBF 2) and higher uptake of micronutrients viz. zinc (75.5 mg/kg), iron (172.16 mg/kg) and manganese content (71.11 mg/kg) were found to be significantly higher in treatment (N100FYM+ CBF 2) having synergistic application of organic and bio-fertilizers. The various growth attributes of broccoli viz. plant height: 42.1 cm, root length: 11 cm, stem diameter: 4.9 cm, fresh weight of shoot: 214.20 g, dry weight of shoot:38.18 g, number of leaves per plant: 29, days taken to visible curd:44 days, head compactness: 1.11 cm, head yield: 153.15 q/acre, number of heads/plant: 6 heads, mean head weight: 88 g and floret stalk length: 12.8 cm was observed to be statistically higher in treatment T10 with combined application of FYM and bacterial isolates (N100FYM+ CBF 2). The study has led to the selection of a plant growth-promoting bacterial consortium as a potential bacterial inoculant for improving the growth, yield and nutrient content in broccoli.