Rhizobacteria promoted growth and yield of tomato plants and control of Fusarium oxysporum f. sp. radicis-lycopersici

Fusarium oxysporum f. sp. radicis-lycopersici (FORL) results in severe losses in the greenhouses and open field tomato crops. In this study, rhizobacteria (RB) were tested on tomato plants for the biological control of FORL and for their ability to promote plant growth and yield. Firstly, 50 RB strains were screened for in vitro growth promotion and biocontrol tests. According to the results of in vitro tests, 9 RB isolates (TR2/1: Pseudomonas fluorescens, TR6/1: P. fluorescens, TR18/1: P. fluorescens, TR21/1: P. putida, TR23/1: P. putida, TR39b: P. fluorescens, 70: P. putida, S5/4: P. putida, 14/1y: P. fluorescens) were selected for in vivo tests realized in growth chamber. A sensitive 'Kardelen F₁' tomato cultivar to FORL was used as plant material. RB were applied as seed coating before sowing and substrate drenching after transplanting, and tested with and without FORL inoculation made before transplanting. RB strains gave rise to significant increase in growth of tomato seedlings, TR2/1 and TR18/1 gave higher values in this respect. RB strains suppressed disease symptoms significantly, TR21/1 and 14/1y were most effective strains for control of FORL. TR 21/1 suppressed disease symptoms by 76%. Four RB (TR2/1, TR18/1, TR 21/1 and 14/1y) were selected for greenhouse experiment, and were tested to determine their effect on growth and productivity of tomato plants in greenhouse under healthy conditions without FORL inoculation. RB increased growth of tomato seedlings and cumulative yield. It was concluded that RB have potential for developing biofertilizers and biopesticides needed in organic farming which avoids the use of synthetic chemicals.