author(s)
Lakshmidevi Paranthaman and Gopalakrishnan Chellappan

abstract
Pseudomonas fluorescens strain TPf12 is being studied as an important biocontrol agent for plant disease management and growth-promoting bacteria in plants. In addition to promoting plant production, previous findings from our research group demonstrated that talc-based P.fluorescens (TPf12) formulation effectively reduced several plant diseases. Modernizing agro-techniques requires the development of a new formulation in which liquid inoculants can play an important part. For the production of liquid formulation, various chemicals such as trehalose, poly vinyl pyrrolidone (PVP), and glycerol were studied. Among these, the glycerol modification retained the higher P. fluorescens (TPf12) population level up to 210 days of storage. In addition, a study was carried out to standardize the dosage of liquid-based TPf12 formulation for seed treatment and seedling dip. For seed treatment and seedling root dip, an application of 10ml kg of seeds and 150ml ha of seedlings was found to be optimal. Without much loss in cell viability, the growth-promoting and antagonistic activities of TPf12 cultures of different ages were found to be greater than up to 180days of storage. The combined effect of seed treatment, seedling dip, and liquid formulation soil drilling documented the minimum incidence of Fusarium wilt on tomato under glasshouse conditions (14.00 per cent) and field conditions (9.54 per cent). Additionally, under glasshouse and field conditions, the liquid formulation increased the yield of tomato fruit compared with untreated control. This research thus provided effective technology for the production of a liquid-based P. fluorescens TPf12 bioformulation.