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Subject: Plant Pathology × Author: Nath, Bharat Chandra × End date: 2017 × Start date: 2013 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    MOLECULAR CHARACTERIZATION OF FEW PLANT GROWTH PROMOTING MICROBES, THEIR COMPATIBILITY ANALYSIS AND UTILITY IN BIOINTENSIVE MANAGEMENT OF BACTERIAL WILT OF TOMATO
    (AAU, Jorhat, 2015) Nath, Bharat Chandra; Bora, L. C.
    Biointensive management of bacterial wilt of tomato (Lycopersicon esculentum Mill) caused by Ralstonia solanacearum was attempted using various bioactive (Plant Growth Promoting) microorganisms viz., Trichoderma viride, Pseudomonas fluorescens, Bacillus subtilis and Azotobacter chroococcum. The molecular characterization of these microorganisms was made to determine their distinctiveness from their close relatives through sequencing of ITS region of ribosomal DNA in case of fungal microorganisms and 16S region of ribosomal DNA in case of bacterial microorganisms. Interactive action among the four bioactive microorganisms showed compatibility in all the treatment combinations in vitro. The antagonistic potential of these bioactive microorganisms was tested in vitro singly or in consortia and per cent inhibition of target pathogen were recorded and analyzed. The highest inhibition (57.70%) against R. solanacearum was recorded against consortia of T. viride+ P. fluorescens + B. subtilis + A. chroococcum followed by T. viride + P. fluorescens + B. subtilis (39.77%) and P. fluorescens + B. subtilis + A. chroococcum (35.65%). Talc based bioformulations were prepared using the best three bioactive microorganisms and their consortia for management of bacterial wilt in pot grown tomato plants during 2013-14 and 2014-15 crop seasons. Applications of the consortial formulations were made as seed treatment, root treatment and soil application. Significantly highest reduction of bacterial wilt incidence (95.09 %) and highest yield (1.692 kg/plant) of tomato was recorded in treatment comprising of T. viride+ P. fluorescens + B. subtilis + A. chroococcum. Correlation studies revealed negative correlation (-0.993) between bacterial wilt incidence and yield of tomato. Screening of 47 tomato genotypes was done under field condition during 2012-13 and 2013-14 crop seasons to assess their degree of tolerance against bacterial wilt pathogen R. solanacearum. Highly resistance reaction (HR) was recorded in Konbilahi (L. pimpinellifolium) followed by resistance reaction (R) in Sel-35, sel-19 and Sel-9. Highest yield was recorded in 2012/TOLCVRES-3 (278.16 q/ha) followed by H-24 (276.85 q/ha) and 2012/TOLCVRES-4 (272.04 q/ha).