Carrot hairy root induction by two different strains of Agrobacterium rhizogenes - MTCC- 532 and MTCC- 2364 grown in YEMA culture media was studied in carrot (Daucus carota). The maximum hairy root induction was observed when carrot was simmered with 48 hours old culture of A. rhizogenes MTCC-532. With different concentrations of acetosyringone (AS) tested, addition of 150 µM/l acetosyringone was found to enhance the transformation frequency up to 75 % and 60 % by A. rhizogenes MTCC-532 and MTCC 2364 strains respectively. Transformation efficiency was highly dependent on the acetosyringone concentrations, type of bacterial strain used and carrot genotype. Freshly harvested carrots showed better hairy root induction. A. rhizogenes transformed hairy roots had the ability to form copious lateral roots as well as a negative geotropic growth habit in a shorter period. The MS medium was found to be the best medium for hairy root mass multiplication which induced high root biomass production and rapid root tip elongation.

Keywords: Arbuscular Mycorrhizae, Acetosyringone, A. rhizogenes , MS medium, Hairy roots.