Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, P.O. Box 1210, Charlottetown, PE, Canada C1A 7M8
PEI Department of Agriculture and Forestry, Plant Health Research & Diagnostics, P.O. Box 1600, Charlottetown, PE, Canada C1A 7N3
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Accepted for publication 6 April 2001.
Disease-free plantlets of 20 potato cultivars commonly grown in Prince Edward Island were inoculated with zoospore suspensions of Phytophthora erythroseptica, the causal agent of pink rot, to determine disease response. All inoculated cultivars developed disease symptoms relative to noninoculated controls, but disease severity differed significantly (P = 0.05) among cultivars. Plantlets of the cultivars Goldrush and Yukon Gold were consistently the most susceptible to the disease, whereas plantlets of cultivars Butte and Russet Burbank were the least susceptible. Most of the cultivars assessed were moderately susceptible to disease. Plantlets of potato cultivars with late-season field maturity were more resistant to disease than those with early or mid-season maturity. Isolates of P. erythroseptica from diverse regions of Prince Edward Island and Maine did not differ significantly (P = 0.05) in pathogenicity. The screening protocol described was a reliable technique to determine the relative resistance of nontuber potato germ plasm to disease, resulting from infection with P. erythroseptica.
The American Phytopathological Society, 2001