Induced Systemic Resistance Against Fusarium Wilt of Sesame by some Chemical Inducers.

Abstract

Incidence of Fusarium wilt disease of sesame caused byFusarium oxysporum f.sp. sesami was successfully controlled under greenhouse and field conditions through enhancing systemic resistance by soaking sesame seeds in concentrations of chemical inducers. Most of the tested treatments were effective in controlling disease under greenhouse conditions. Salicylic acid (2 and 4mM), Bion (4mM), CoSO4 (1 and 2ppm) and IBA (100 and 200 ppm) were the most effective treatments for controlling the disease because they maximized the percentage of healthy plants compared with the untreated controls. Under field conditions, most of the treatments were also effective in controlling the disease and increasing seed yield. Salicylic acid (2 and 4mM), Bion (4mM), CoSO4 (1 and 2ppm) and IBA (200 ppm) were the most effective treatments in controlling disease while, salicylic acid (2 mM), Bion (4mM), CoSO4 (2ppm) and IBA (200 ppm) were the most effective treatments in increasing seed yield. Relationship between induced systemic resistance and some biochemical changes like increases in activity of oxidative enzymes (peroxidase and polyphenoloxidase), phenolic compounds, sugars and total free amino acids was observed in root tissues of healthy sesame plants that grown from treated sesame seeds compared with those grown from untreated seeds. Cobalt sulphate at 2ppm, salicylic acid at 2mM and IBA at 200 ppm were the most effective treatments for stimulating these defense mechanisms with few exceptions.