Increased Tolerance to Fusarium Wilt in Mycorrhizal Strawberry Plants Raised by Capillary Watering Methods

Tolerance to fusarium wilt, caused by Fusarium oxysporum f, sp. fragariae (Fof), in strawberry (Fragaria×ananassa Duch., cv. Nohime) plants infected with arbuscular mycorrhizal (AM) fungi (Gigaspora margarita, Glomus fasciculatum, Gl. mosseae, Gl. sp. R10, Gl. aggregatum) was estimated under capillary watering conditions. Thirty days after Fof inoculation, the incidence of fusarium wilt ranged from a minimum of 22.2% in Gl. mosseae plot and a maximum of 100% in non-AM one ; the incidence varied, depending on AM fungal species. Incidence and severity of browned vessels and roots became lower in AM plots than in non-AM one. Non-diseased and diseased AM plants had higher dry weight of shoots and roots than did diseased non-AM plants. No significant difference in phosphorus concentration in plants appeared between non-AM and AM plots 11 weeks after AM fungus inoculation (just before Fof inoculation) and 30 days after Fof inoculation. These findings suggest that tolerance to fusarium wilt occurred in AM fungusinfected strawberry plants, and the effect had less association with phosphorus concentration in plants.