EVALUATION OF MICROBIAL CONSORTIA OF BIOCONTROL AGENTS AND PGPRS FOR ENHANCING SEEDLING QUALITY OF SOLANACEOUS VEGETABLES MAINA, C.C. PAK 9018 DEPARTMENT OF AGRICULTURAL MICROBIOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES BANGALORE 2012 EVALUATION OF MICROBIAL CONSORTIA OF BIOCONTROL AGENTS AND PGPRS FOR ENHANCING SEEDLING QUALITY OF SOLANACEOUS VEGETABLES MAINA, C.C PAK 9018 Thesis submitted to the University of Agricultural Sciences, Bangalore in partial fulfillment of the requirements for the award of the degree of Doctor of Philosophy in AGRICULTURAL MICROBIOLOGY BANGALORE JULY, 2012 Affectionately Dedicated to my Husband & Kids DEPARTMENT OF AGRICULTURAL MICROBIOLOGY UNIVERSITY OF AGRICULTURAL SCIENCES BANGALORE CERTIFICATE This is to certify that the thesis entitled “EVALUATION OF MICROBIAL CONSORTIA OF BIOCONTROL AGENTS AND PGPRS FOR ENHANCING SEEDLING QUALITY OF SOLANACEOUS VEGETABLES” submitted by Mrs. MAINA, C.C., ID No. PAK 9018 in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in AGRICULTURAL MICROBIOLOGY to the University of Agricultural Sciences, Bangalore, is a record of research work carried out by her during the period of her study in this University under my guidance and supervision and thesis has not previously formed the basis for the award of any degree, diploma, associateship, fellowship or any other similar titles. BANGALORE Dr. M.K. SHIVAPRAKASH JULY, 2012 Professor and Head Dept. of Agricultural Microbiology Major Advisor APPROVED BY: Chairman : ___________________________ (M.K. SHIVAPRAKASH) Members : 1. ___________________________ (K. R. SREERAMULU) 2. ___________________________ (L. KRISHNA NAIK) 3. ___________________________ (NAGARAJU) External Examiner 4. ___________________________ (S.P. SUNDARAM) (S. SRIRAM) ACKNOWLEDGEMENT Evaluation of microbial consortia of biocontrol agents and PGPRs for enhancing seedling quality of solanaceous vegetables Maina, C.C. Thesis Abstract Present investigation was undertaken to evaluate microbial consortia of biocontrol agents and PGPRs for enhancing the seedling quality of solanaceous vegetables. The most virulent pathogens isolated belonged to genera Pythium sp., Phytophthora sp., Fusarium sp. and Rhizoctonia sp. The biocontrol agents Pseudomonas fluorescens (NBAII-Pf1), Bacillus subtilis (UASBR-Bs1) and Trichoderma harzianum (NBAII-TH1) were found to be most effective against these virulent pathogens. Maximum inhibition of pathogens was recorded by Trichoderma harzianum through production of volatile metabolites. All the three biocontrol agents were found to be compatible with the PGPRs Azotobacter chroococcum and Bacillus megaterium and were used to develop consortia. The survival of the above mentioned organisms as consortia was best in the combination of coirpith (65 %), soilrite (25 %) and pongamia cake (10 %) in which the highest population was recorded in the second and third week of incubation and was chosen for raising seedlings for greenhouse and field evaluation studies. The studies under greenhouse conditions revealed that the substrate enriched with consortia of selected biocontrol agents, PGPRs and Glomus intraradices were more effective in disease suppression and growth promotion activities of tomato, chilli and brinjal seedlings under nursery conditions thereby enhancing the biocontrol efficiency and seedling vigour of the seedlings. Solanaceous seedlings raised with the substrate enriched with consortia of Azotobacter chroococcum, Bacillus megaterium, Pseudomonas fluorescens, Bacillus subtilis Trichoderma harzianum and Glomus intraradices,established better under field conditions with less disease incidence, better growth and yield in an ecofriendly manner. July, 2012 Dr. M. K. 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PÉëÃvÀæ CzsÀåAiÀÄ£ÀzÀ AiÀÄÄ eÉÊ«PÀ ¤AiÀÄAvÀæt KeÉAmïìUÀ¼ÁzÀ ¸ÀÆåqÉÆêÉÆ£Á¸ï ¥ÀÆègɸɣï, ¨Áå¹®¸ï ¸À©Ö°Ã¸ï ªÀÄvÀÄÛ mÉæöÊPÉÆÃqÀªÀiÁð ºÁfðAiÀiÁ£ÀªÀiï ªÀÄvÀÄÛ ¦.f.¦.DgïUÀ¼ÁzÀ CdmÉÆçåPÀÖgï PÀÆæPÁPÀªÀiï, ¨Áå¹®¸ï ªÉÄUÁyÃjAiÀĪÀiï, ªÉÄÊPÉÆgÉÊdó MPÉÆ lUÀ¼À£ÀÄß P §¼À¹ ¨É¼À¹zÀ ¸À¹UÀ¼ÀÄ GvÀÛªÀÄ ¨É¼ÀªÀtÂUÉ ªÀÄvÀÄÛ E¼ÀĪÀj eÉÆvÉUÀ PÀrªÉÄ gÉÆÃUÀ ªÁå¦Û¬ÄAzÀ ZÉ£ÁßV ¸Áܦ¸À®ànÖzÀÄÝ F ¸ÀAAiÉÆd£ÉAiÀÄ£ÀÄß ¥Àj¸ÀgÀ¸Éßû «zsÀzÀ°è §¼À¹PÉƼÀ §ºÀÄzÁVzÉ. ¼ dįÉÊ, 2012 PÀȶ ¸ÀÆPÀë÷äfë±Á¸ÀÛç «¨sÁUÀ PÀÈ.«.«., f.PÉ.«.PÉ qÁ||. JA. PÉ. ²ªÀ¥ÀæPÁ±ï ¨ÉAUÀ¼ÀÆgÀÄ-65 (¥ÀæzsÁ£À ¸À®ºÉUÁgÀgÀÄ) CONTENTS Chapter Title Page No. I INTRODUCTION 1-4 II REVIEW OF LITERATURE 5-37 III MATERIAL AND METHODS 38-57 IV EXPERIMENTAL RESULTS 58-122 V DISCUSSION 123-142 VI SUMMARY 143-146 VII REFERENCES 147-179 APPENDIX LIST OF TABLES Table Page TITLE No. No. Details of isolates of soil borne plant pathogens of solanaceous crops 1 59 and their pathogenicity. Characteristics of virulent isolates of soil borne plant pathogens of 2 61 solanaceous crops. Antagonistic properties of bacterial biocontrol agents against of 3 62 virulent soil borne pathogens of solanaceous crops in vitro Antagonistic properties of fungal biocontrol agents against virulant 4 64 soil borne pathogens of solanaceous crops in vitro Elucidation of mechanisms of inhibition by biocontrol agents against 5 65 soil borne pathogens of solanaceous crops. Compatibility scores between biocontrol agents and PGPRs in dual 6 65 culture. 7 Compatibility between biocontrol agents and PGPRs in agar wells. 67 Population dynamics of Azotobacter chroococcum in different 8 69 combinations of nursery substrates. Population dynamics of Bacillus megaterium in different 9 71 combinations of nursery substrates. Population dynamics of Pseudomonas fluorescens in different 10 73 combinations of nursery substrates. Population dynamics of Bacillus subtilis different combinations of 11 76 nursery substrates. Population dynamics of Trichoderma harzianum in different 12 78 combinations of nursery substrates. Biocontrol efficiency of consortia of promising microbial agents on 13 81 tomato crop in nursery stage under green house condition. Efficacy of consortia of promising microbial agents on enhancing 14 seedling vigour of tomato crop in nursery stage under green house 83 condition. Biocontrol efficiency of consortia of promising microbial agents on 15 86 chilli crop in nursery stage under green house condition.