Identification and Characterization of Fusarium Species Associated With Amaranth (Amaranthus Species) Wilt Disease in the Semi-deciduous and Guinea Savannah Agro-ecological Zones of Ghana

Fusarium wilt is a major constraint in amaranth production in Africa; the disease can lead to total crop failure. However, few studies have identified Fusarium species associated with amaranth diseases in Ghana. The study was conducted to identify Fusarium species causing wilt in amaranth in the Semi-deciduous and Guinea Savannah Agro-ecological zones of Ghana and determine variations in isolates. Using standard laboratory procedures, fungal pathogens were isolated and culture characteristics studied. Variations in virulence were determined using root dip method. Sequence analysis of the internal transcribed spacer region of isolates was carried out for species identfication. Based on morphological features complemented by sequence analysis; Fusarium equiseti, F. oxysporum, F. solani and F. proliferatum were identified. Fusarium equiseti was the dominant species appearing in 82% of isolates. All the isolates were pathogenic. Based on virulence level, 9% of the isolates were classified as very highly virulent whilst 56% were weakly virulent. Genetically, isolates clustered into four groups irrespective of origin. The work identified and classified Fusarium species causing amaranth wilt in Ghana.