甘藷基腐病之病原及其對六種不同甘藷品種之感受性分析

Analyses for the Causal Agent of Sweet Potato Foot Rot Disease and Its Susceptibility on Six Sweet Potato Cultivars

"甘藷（Ipomoea batatas(L.) Lam.）在臺灣種植的面積在9,000公頃以上，其塊根、莖葉都可食用，甘藷品種多元，有以塊根為食用標的之品種供煮食、烤藷等用途，亦有葉用甘藷品種，在臺灣各地普遍種植。2009年4月，種植在臺中區農業改良場內的葉用甘藷出現基部黑化、葉片黃化、植株生長勢弱的徵狀，之後在中部地區調查，在彰化的花壇、埔鹽、福興、二水，臺中的清水、大安、后里都發現類似癥狀的甘藷植株。"

"In 2009, sweet potatoes with foot rot symptom were collected in Changhua and Taichung. Fungi isolated from the symptomatic tissues were diagnosed Phomopsis destruens (Harter) Boerema, the causal agent of sweet potato foot rot disease, based on the morphology and host range. The internal transcribed spacer (ITS) nucleotide sequences of the fungal isolates were highly identical to that of the foot rot disease pathogen SPPD-1 isolate. All plants propagated from the diseased cutting showed symptoms, but the healthy plants could be obtained using sterilized substrate to cultivate the disease-free parts of the infected sweet potatoes. Inoculation of P. destruens on different cultivars of sweet potatoes, showing that all six tested cultivars 'Tainung No.57', 'Tainung No.66', 'Tainung No.71', 'Tainung No.72', 'Tainung No.73' and 'Taoyuan No.2' were infected. However, the area under disease progress curve (AUDPC) values of the six cultivars were not significantly different. Linear regression analysis using the severity data of foot rot disease showed the relationship of the disease severities over time (weeks) was y = -7.55 + 1.906x."