Potential of native strains of Bacillus spp. against Fusarium wilt of watermelon

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dc.contributor.advisorButtar, Daljeet Singh
dc.contributor.authorGeetika
dc.date.accessioned2020-07-15T09:43:41Z
dc.date.available2020-07-15T09:43:41Z
dc.date.issued2020
dc.description.abstractFusarium wilt of watermelon caused by Fusarium oxysporum f.sp. niveum is a serious disease of watermelon growing areas of Punjab. Rhizosphere soil samples were collected from watermelon fields of Ludhiana, Jalandhar and Kapurthala districts and analysed for antagonistic microflora. Fifty isolates of Bacillus were isolated from the soil samples which were collected from rhizosphere soil of watermelon grown different districts of Punjab using serial dilution plating technique on the mannitol egg yolk polymixin medium. Out of 50 isolates, fifteen isolates of Bacillus were identified and purified based on morphological and biochemical character for further studies. The purified fifteen isolates of Bacillus were screened against the Fusarium oxysporum f.sp. niveum using dual-culture technique, volatile, non-volatiles and siderophore production under the laboratory conditions. B1 and B3 isolates of Bacillus spp. showed maximum (2.26 cm) zone of inhibition against Fusarium oxysporum f.sp. niveum under dual culture technique. These isolates showed 76.94 % and 79.20 % inhibition of pathogen in volatiles and non-volatiles production respectively. B1 isolate of Bacillus also showed highest chitinase and β-1,3 glucanase activity of 2.31 and 1.82 unit/ml, respectively. Similarly siderophore production in terms of halo zone (22.69 mm) was maximum in B1 isolate of Bacillus on Chrome-Azurol S media plate. The sequence of DNA showed on NCBI Blast that the nucleotide homology of the isolate B1 showed similarity with Bacillus subtilis strain 8102 (Accession number HQ123475.1). The isolate B3 based on nucleotide homology exhibited its similarity with Bacillus cereus strain LAR2-3 (Accession number KT151933.1). Efficacy of talc based bioformulations of Bacillus subtilis B1 and Bacillus cereus B3 were examined alone @ 5, 10 and 15g per kg of seed, in soil application ( 15 g per kg of soil) and seed + soil application included combination of both treatments (seed+soil). The chemical Bavistin @1.5 g per kg of seed was taken as standard chemical check. B 3 Bacillus cereus isolate applied as seed + soil @ 15g/kg of seed+soil treatment, showed maximum percentage of seed germination (93.33%), minimum percentage of disease incidence (6.67%) and maximum disease inhibition (87.51%) in watermelon plants in pots. Similar results were observed in B 1 Bacillus subtilis applied as seed + soil treatment @15g/kg of seed+soil showed maximum percentage of seed germination (90.00%), minimum percentage of disease incidence (10.00%) and maximum disease inhibition (81.24%) in watermelon plants in pots in kharif 2018 season. Similar trend was observed in kharif 2019 season. The talcum based bioformulations of these two isolates of Bacillus spp. were also further applied as seed treatment, soil treatment and seed + soil treatment and evaluated against wilt pathogen under field conditions. The maximum seed germination (95.83%) was recorded in both treatments of Bacillus subtilis B1 and Bacillus cereus B3 seed + soil @15 g per kg of seed/soil which was at par with the chemical treatment. The minimum wilt disease incidence (8.33%) was observed in the treatment of Bacillus cereus B 3 seed + soil @15 g/kg seed+soil followed by B1 seed + soil @15g/kg seed+soil treatment was 12.50 per cent. In addition to that these isolates of Bacillus spp. also promoted the plant growth parameter like root length, shoot length, their fresh and dry weight and ultimately increased the fruit yield of watermelon under both pots and field conditions. For the rhizosphere competence of the antagonist soil sampling at 15 days interval was done which showed that desirable colony forming unit count was present throughout the crop period in order to manage the pathogen effectively both under pots and field conditions. Maximum shelf life of talc based powder bioformulation of Bacillus subtilis B1 and Bacillus cereus B3 were recorded at low temperature storage (5°C) in polythene bags package. Therefore the finding concluded that Bacillus subtilis B1 and Bacillus cereus B3 significantly decreased the wilt incidence as compared to untreated control both under pot and field condition respectively. Both of these isolates significantly enhanced plant growth parameter and fruit yield. Hence enhanced the production and productivity of watermelon in Punjab condition.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810149185
dc.keywordsFusarium wilt of watermelon, Bacillus spp., Bioformulationen_US
dc.language.isoenen_US
dc.pages100en_US
dc.publisherPunjab Agricultural University, Ludhianaen_US
dc.research.problemPotential of native strains of Bacillus spp. against Fusarium wilt of watermelonen_US
dc.subPlant Pathologyen_US
dc.subjectnullen_US
dc.themePotential of native strains of Bacillus spp. against Fusarium wilt of watermelonen_US
dc.these.typePh.Den_US
dc.titlePotential of native strains of Bacillus spp. against Fusarium wilt of watermelonen_US
dc.typeThesisen_US
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