Asian Soil Research Journal

The current study reports the effect of various cultural parameters on the gibberellic acid (GA) by Fusarium sp. isolated from an agricultural field of Murshidabad district in West Bengal, India. Gibberellin is one of the principal plant growth regulators that influence the overall developmental processes in angiosperms. The Fusarium sp. was isolated by soil dilution plate technique on selective pentachloronitrobenzene (PCNB) medium. The isolate was identified and subsequently characterized by the routine morphological studies and molecular analysis. Various physiological parameters viz., growth media, carbon and nitrogen sources, incubation temperature and pH of the culture medium were taken into consideration for determining their effect on the phytohormone production and subsequent optimization of the culture conditions. GA production was found to be highest in CD broth. Among the carbohydrate sources used, sucrose (7300 µg/ml), dextrose (7150 µg/ml) and maltose (6650 µg/ml) were found to be most conducive for GA production. Among the nitrogen sources, glycine (7360 µg/ml) and sodium nitrate (7250 µg/ml) were found to be most stimulatory in GA production. Interestingly, with the increase in pH, GA production was also found to be increased. Maximum GA production was recorded at pH 10 (7800 µg/ml). GA production was found equally well in temperature range 14-32°C (7000-7160 µg/ml).