IDENTIFICATION OF EFFECTIVE ISOLATE OF PSEUDOMONAS FROM THE SOILS OF SOUTHERN TELANGANA ZONE AGAINST CASTOR WILT PATHOGEN

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dc.contributor.advisorSUBHASH REDDY
dc.contributor.authorJAYAMMA, P.
dc.date.accessioned2016-07-28T13:27:49Z
dc.date.available2016-07-28T13:27:49Z
dc.date.issued2009
dc.description.abstractWilt of castor caused by Fusarium oxysporum f.sp. ricini which was earlier considered as a disease of minor importance, now it became a major disease and an impediment in the cultivation of the castor. Continuous use of agrochemicals in pest and disease control leads to environment, soil and water pollution, where as biological control of diseases is long lasting, less expensive, eco-friendly and harmless to non target organisms. Keeping in view the benefits of biological control of plant pathogens the present investigation is carried out. Symptoms of the disease on seedlings showed characteristic yellowing and bronzing of cotyledonary leaves associated with degenerated root system. Symptoms on grownup plants manifested as stunting of the plant, yellowing of leaves, production of black streaks on stems and discolouration of roots. The fungus associated with the disease was isolated and identified as Fusarium oxysporum f.sp. ricini and its pathogenicity was proved under greenhouse conditions. Microorganisms are known to grow in the rhizosphere and provide frontline defence for roots against the attack by plant pathogens. In the present study, fluorescent Pseudomonads were isolated from the rhizosphere of crop plants like sorghum, maize, groundnut, chilli, tomato, castor and also from various forest plants. Twenty seven isolates were obtained from the 70 rhizosphere soil samples. Out of which, eighteen isolates were identified as fluorescent Pseudomonads based on their fluorescence nature under UV- light on Pseudomonas agar. Isolated fluorescent Pseudomonads were screened against Fusarium oxysporum f.sp. ricini under in vitro conditions using dual culture plate technique to test the antagonistic potential. Three fluorescent Pseudomonas isolates (STPF-11, STPF-14 and STPF-18) were found to be potential antagonists against the tested fungal pathogen. Under field conditions, agrochemicals like fungicides, insecticides and herbicides etc. are used to control plant diseases and pests. In addition to agrochemicals biocontrol agents are also used by farmers for controlling some diseases. Because of this, the potential antagonistic PF (fluorescent Pseudomonads) isolates were tested for their compatibility with the commonly used agrochemicals. Among the different agrochemicals tested carbendazim, chlorpyriphos and pendimethalin were found to be more compatible with PF isolates. Disease management strategy was developed for wilt of castor under greenhouse conditions. Among the treatments, treatment T3 (seed treatment with STPF-14 isolate + soil application of Farm Yard Manure (FYM) incubated STPF -14 isolate) was highly effective with least per cent disease incidence of 26.56 per cent at 45 days after sowing. This treatment not only reduced the disease incidence to a maximum extent, but also recorded maximum plant height (27.32 cm) root length (6.36 cm) and maximum fresh (21.32 g) and maximum dry weight (5.19 g) of castor when compared to other treatments.en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/70159
dc.language.isoenen_US
dc.publisherACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY RAJENDRANAGAR, HYDERABADen_US
dc.relation.ispartofseriesD8506;
dc.subAgricultural Microbiology
dc.subjectPSEUDOMONAS, SOILS, SOUTHERN, TELANGANA, ZONE, CASTOR, WILT, PATHOGENen_US
dc.these.typeM.Sc
dc.titleIDENTIFICATION OF EFFECTIVE ISOLATE OF PSEUDOMONAS FROM THE SOILS OF SOUTHERN TELANGANA ZONE AGAINST CASTOR WILT PATHOGENen_US
dc.typeThesisen_US
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IDENTIFICATION OF EFFECTIVE ISOLATE OF PSEUDOMONAS FROM THE SOILS OF SOUTHERN TELANGANA ZONE AGAINST CASTOR WILT PATHOGEN
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