Silicon Suppresses Fusarium Wilt Development in Banana Plants

This study aimed to determine the effect of silicon (Si) in reducing the symptoms of Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), on banana plants. Banana seedlings of Grand Nain (resistant) and Maca (susceptible) were grown in plastic trays amended with 0 (-Si) or 0.39 g Si (+Si) per kg of soil and inoculated with Foc at 60 days after transplanting. The Si concentration in the roots and rhizome-pseudostem significantly increased by 30.26 and 58.82%, respectively, for the +Si treatment compared with -Si treatment. The Si concentration in the roots and rhizome-pseudostem of Grand Nain plants was, respectively, 11.57 and 37.04% greater than that found in Maca. The +Si plants showed a reduction of 12.37, 49.81, 51.87 and 20.39%, respectively, for the area under reflex leaf symptoms progress curve, the area under root symptoms progress curve, the area under disease progress curve and the area under asymptomatic fungal colonization of tissue progress curve compared with -Si plants. The area under darkening of rhizome-pseudostem progress curve (AUDRPPC) of Maca significantly increased by 15.98% for the -Si treatment in comparison with the +Si treatment. For the +Si treatment, the AUDRPPC of the plants from the Maca cultivar significantly decreased by 20.59% in comparison with the plants from the Grand Nain cultivar. The area under relative lesion length progress curve (AURLLPC) of the plants from the Maca cultivar significantly decreased by 41.54% for the +Si treatment in comparison with the -Si treatment. There was no significant difference between the -Si and +Si treatments in the AUDRPPC and AURLLPC of Grand Nain. For the +Si treatment, the AURLLPC of Grand Nain significantly decreased by 9.23% in comparison with Maca. There was no significant difference between the Grand Nain and Maca for the AUDRPPC and AURLLPC in the -Si treatment. The findings of this study show that supplying Si to banana plants, especially to a susceptible cultivar to Foc, had a great potential in reducing the intensity of Fusarium wilt and may play a key role in disease management when banana plants are cultivated in Si-deficient soils infested by this pathogen.