Biological hardening of tissue culture raised tea plants through rhizosphere bacteria

Four antagonistic bacterial isolates, Bacillus subtilis, Bacillus sp., Pseu domonas corrugata 1 and P. corrugata 2, isolated from the rhizosphere of te a plants growing in different geographical locations in India, were tested as microbial inoculants for hardening of tissue-cultured tea plants raised in the laboratory prior to the transfer to open land. Bacterial inoculation s resulted in enhanced survival (up to 100, 96, and 88%), as against 50, 52 , and 36% survival observed in the corresponding control plants, in rainy, winter and summer seasons, respectively. Rhizoplane and rhizosphere soil an alyses showed that the major biotic factor responsible for mortality follow ing the transfer of tissue culture raised plants to soil was fungal attack (Fusarium oxysporum). Bacterial inoculations also resulted in plant growth promotion of tissue culture as well as seed raised plants of tea.