Effects of Arbuscular Mycorrhizal Fungi on Disease Suppression and Yield of Tomato Under Fusarium Wilt Challenge in Kano State, North West Nigeria

Arbuscular mycorrhizal fungi (AMF) are known to confer multiple benefits to host plants, including enhanced nutrient uptake, drought tolerance, and systemic resistance against soilborne pathogens. Their potential role in suppressing Fusarium wilt of tomato in Nigerian irrigated production systems has not been empirically tested under local conditions. This study investigated the effects of inoculation with three AMF species, Rhizophagus irregularis, Funneliformis mosseae, and Glomus clarum, individually and as a consortium, on Fusarium oxysporum f. sp. lycopersici wilt incidence, plant growth parameters, and marketable yield in tomato under Kano State field conditions. A randomised complete block design was used across two field sites over two growing seasons. AMF colonisation rates in root tissues were quantified by microscopy at 30, 60, and 90 days post-transplanting. All three AMF species established colonisation rates above 60 percent in inoculated treatments. The R. irregularis plus F. mosseae consortium treatment showed the greatest wilt suppression, reducing disease incidence by 58 percent compared to non-inoculated Fusarium-challenged controls, and was associated with significantly elevated root chitinase activity consistent with induced systemic resistance. Marketable fruit yield in consortium-inoculated plants exceeded uninoculated controls by 37 percent. Single-species AMF treatments provided intermediate protection. Root phosphorus content was higher in all AMF-inoculated plants, suggesting that nutritional priming contributed to disease suppression alongside direct systemic effects. The study recommends consortium AMF inoculants as a component of integrated wilt management in Kano tomato systems. Keywords: arbuscular mycorrhizal fungi, Fusarium wilt, tomato, disease suppression, Kano State.