PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

The plant hormones application increased the resistance in rice plants against brown leaf spot disease. That’s, why, the effect of five plant hormones (salicylic acid, citric Acid, K₂HPO₄, KH₂PO₄, benzoic acid) on the resistance of rice plants (Oryzae sativa L.) to brown leaf spot disease cause by Bipolaris oryzae were evaluated in field. The results showed that all of the plant hormones evaluated distinctly increased resistance of rice to BLS disease. All plant hormones employed at three concentrations (0.5, 0.75 and 1%), significantly decreased the incidence of brown leaf spot. Salicylic Acid exhibited minimum disease incidence (%) as compared to benzoic acid, K₂HPO₄, KH₂PO₄, and citric acid under greenhouse and field condition as compared to control. Interaction between treatments and concentration (T×C) expressed that salicylic acid expressed minimum disease incidence at 0.05% (22.52), 0.75% (19.92) and 1.0% (17.32) %, followed by benzoic acid (27.26,25.23,22.92), K₂HPO₄ (28.78,25.72,22.83), KH₂PO₄ (32.61,29.94,27.62) and citric acid (36.96,34.27,31.55) % respectively in field condition. These results recommended that plant hormones have key role in controlling the brown leaf spot disease through inducing resistance in rice plants.