Abstract:Foot rot of sweetpotato caused by Diaporthe destruens is a new disease in the southeast coast of Zhejiang Province. In order to explore resistant germplasm resources and explore the method of resistance identification in natural induced field, We investigated and identified the resistance of 126 sweetpotato germplasm resources, and analyzed the changes of disease symptom in late growth period of sweetpotato and effects of resistance on yield loss rate of fresh storage root.. The results showed that the control variety Zheshu255 was high resistant, Zheshu 38 was resistant and Zheshu 13 was high susceptible.Of which, no high resistance germplasm were identified among 89 new collected resources and local main varieties only 3 accessions were resistant, when over 65% of the resources were high susceptible. 13 resistant accessions were identified from the 34 progenies of resistant variety Zheshu255, including 6 high resistant and 2 resistant accessions. There were significant changes of disease symptom in the late growth period of sweet potato, especially the disease index sharply increased from the growth period of 120 d to 135 d in moderate resistant and susceptible germplasm. The disease grade of 93.8% of the total susceptible plants was 4 at the growth period of 135 d. Eventually, most of the susceptible plants rotted throughly at the base of stem or died . The yield loss rate of sweetpotato with good resistance (high resistance or resistance) could be controlled below 15% , while the yield loss rate of susceptible varieties was over 65% , even no harvest. In a word, the resistant germplasm resources of foot rot disease of sweetpotato were scarce, the good resistant breeding materials could be obtained through the conventional hybrid breeding of the resistant parents, and the incidence and disease index might be used as the identification index of resistance to foot rot of sweetpotato in natural induced field.