北海道におけるサツマイモつる割病の発生と品種別感受性の差異

抄録

Stem rot of sweet potato（Ipomoea batatas）was found in Hokkaido, Japan in July 2012. Two Fusarium isolates from a diseased stem were highly pathogenic to sweet potato. Based on morphological observation using synthetic low-nutrient agar（SNA）and potato dextrose agar（PDA）cultures, the isolates were identified as Fusarium oxysporum. From the pathogenicity to Ipomoea tricolor cv. Heavenly Blue, the forma specialis was identified as f. sp. batatas. The susceptibility of fourteen cultivars including lines of sweet potato was evaluated from the percentage of vascular browning length after dipping cuttings of stems into the conidium suspension of the pathogen. The reaction of the cultivars varied from highly resistant（cultivars ‘Beniharuka’ and ‘Tamayutaka’）to susceptible.