Effect of Gibberellic acid produced by the fungus Gibberella fujikuroi on the growth factors of rice seed

Bakanae disease and Foot rot of rice is one of the rice seed-borne diseases that observed from nursery to paddy field. Most important symptoms of disease is production of elongated and abnormal seedlings from contaminated seeds on the effect of Gibberellic acid in nursery and field. This investigation, effect of Gibberellic acid produced by Gibberella fujikuroi evaluated on the increase of stem and root growth and mortality of Hashemi cultivar seeds. Hashemi’s cultivar seeds inoculated by Gibberella fujikuroi conidial suspension isolated from infected seedlings from rice fields of Guilan province. Rate of increase of growth by measuring of stem and root length and number of dead seeds once every five days and amount of Gibberellic acid produced by Gibberella fujikuroi isolates was determined using High Performance Liquid Chromatography (HPLC). Results of quantitative determination of Gibberellic acid showed that all isolates were studied have ability to produce this hormone. There were not found any significant correlation between the amount of production of Gibberellin hormone in pathogen and increase of stem and root length from germination of inoculated seeds of Hashemi cultivar and also number of dead seeds.