Effect of iodine biofortification on incidence and severity of Fusarium wilt and yield of tomato (<i>Solanum lycopersicum</i> L.)

Abstract

Tomato is often attacked by wilt caused by Fusarium oxysporium. Iodine is known to have fungistatic effect in pathogen control. The present experiment was aimed at determining the effect of iodine compounds (potassium iodide, KI and potassium iodate, KIO₃) on incidence and severity of Fusarium wilt and yield of two tomato accessions, FUNAABTO/106 and FUNAABTO/123. The experiment was conducted in the screenhouse and on the field. KI was applied at concentrations of 1, 2, 3, 5 mM while KIO₃ was applied at concentrations of 0.5, 1, 2, 3 mM. The untreated plots served as control. Results showed that FUNAABTO/106 treated with 0.5 mM KIO₃ in the screenhouse and on the field had the least (0.00%) disease incidence. Disease severity was significantly (p ≤ 0.05) lower (1.00) in the screenhouse in pots containing FUNAABTO/106 treated with 1 mM KIO₃. On the field, FUNAABTO/106 treated with 0.5 mM KIO₃ had the least (1.17) disease severity. FUNAABTO/106 treated with 0.5 mM KIO₃ in the screenhouse and on the field were significantly higher (1.65t/ha and 18.54t/ha respectively) in yield. The study concluded that application of iodine compounds at lower concentrations reduced the incidence and severity of Fusarium wilt and increased the yield of tomato.

Keywords: Potassium iodate (KIO₃), Potassium iodide (KI), Fusarium oxysporium