Growth and virulence of Bacillus thuringiensis on cereals
| dc.contributor.advisor | Joshi, Neelam | |
| dc.contributor.author | Jasdeep Kaur | |
| dc.date.accessioned | 2016-08-22T16:02:38Z | |
| dc.date.available | 2016-08-22T16:02:38Z | |
| dc.date.issued | 2016 | |
| dc.description.abstract | Five Bacillus thuringiensis isolates including two procured isolates (B. thuringiensis MTCC 868 and MTCC 4715) and three native isolates (Bt-4, Bt-10 and PAU Bt) were evaluated on different cereal based medium, their effect of incubation time, pH and various additives on the persistence of bacteria and its virulence against Spodoptera litura. Among various cereals based liquid media, wheat recorded maximum spore count (28.07×108 CFU/ ml) and was significantly better than maize, rice and sorghum. The growth parameters viz incubation time and pH were recorded and was found that maximum spore count (27.87×108 CFU/ ml) was recorded after 72 hours of incubation which was at par with 96 and 120 hours. The maximum spore count (27.73×108 CFU/ ml) was recorded at pH 7.5 and was at par with spore count (25.60×108 CFU/ ml) at pH 7.2. Influence of different additives viz carboxymethyl cellulose, triton x 100, boric acid, methyl-p-hydroxybenzoate and glycerol on the persistence of B. thuringiensis isolates was studied. It was found that the spore count varied with the different concentrations of additives. The maximum spore count 26.33×108, 24.80×108, 23.93×108, 23.20×108 and 20.53×108 CFU/ ml were recorded at 0.1 per cent concentration of triton x 100 and one per cent concentration of glycerol, methyl-phydroxybenzoate, boric acid and carboxymethyl cellulose respectively. Laboratory bioassay studies were conducted against the second instar larvae of S litura along with one commercial formulation of B. thuringiensis var. kurstaki (DELFIN® WG) and untreated control. It was found that among all Bacillus isolates maximum mortality (76.67%) was recorded in MTCC 868 at higher concentration (2.0%) after ten days of treatment. However, DELFIN® WG formulation recorded maximum mortality of 99.98 per cent mortality against the second instar larvae of S. litura after seven days of treatment at all concentrations. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/73335 | |
| dc.language.iso | en | en_US |
| dc.publisher | Punjab Agricultural University, Ludhiana | en_US |
| dc.sub | Microbiology | |
| dc.subject | Bacillus thuringiensis, Bioassay, Cereal based media, Spodoptera litura, spore counts | en_US |
| dc.these.type | M.Sc | |
| dc.title | Growth and virulence of Bacillus thuringiensis on cereals | en_US |
| dc.type | Thesis | en_US |