| dc.description.abstract | Tuber blight may result from infection of wounded or unwounded potato tubers
exposed to sporangia from foliar blight, soil, or blighted tubers. However, there are
limited data on the prediction of tuber blight in field or storage environment based on in
vitro assays. To assess this relationship, potato cultivars with foliar blight resistance (Rgenes)
and general resistance were evaluated for tuber blight incited by Phytophthora
infestans (US-1) based on wound-induced and unwounded tuber inoculations. Surface
lesion diameter, lesion depth, and frequency distribution of blighted tubers were assessed
in in vitro assays and tuber blight incidence determined in field experiments. Significant
differences (P < 0.05) in lesion diameter and depth were recorded among cultivars.
Surface lesion diameter, depth, and index ranged from 5 to 40, 2 to 16.3, and 15 to 656
mm, respectively, in wound-inoculated tubers. In nonwounded tuber assays, the
incidence of blighted tubers ranged from 0% to 8.7% in both years. Tuber blight
infection of potato cultivars varied between years in field studies. Although tuber
infection differed among cultivars, the frequency of blighted tubers had a normal
statistical distribution irrespective of R-genes, implying that foliar resistance may have
limited effect on tuber blight occurrence based on in vitro experiments. Prediction of
tuber blight based on inoculation assays can be effectively used to estimate and manage
blight development in storage environments. | en |
