01694nas a2200217 4500008004100000022001400041245007900055210006900134260002900203300001100232490000700243520106400250100001501314700001701329700001301346700001701359700001301376700001301389700001901402856005501421 2011 eng d a1439-032900aPhenotypic differences among three clonal lineages of Phytophthora ramorum0 aPhenotypic differences among three clonal lineages of Phytophtho bBlackwell Publishing Ltd a7–140 v413 a

There are three major clonal lineages of Phytophthora ramorum present in North America and Europe named NA1, NA2, and EU1. Twenty-three isolates representing all three lineages were evaluated for phenotype including (i) aggressiveness on detached Rhododendron leaves and (ii) growth rate at minimum, optimum, and maximum temperatures. Closely related species P. foliorum and P. hibernalis were included in phenotypic tests since these species are encountered in nursery surveys for P. ramorum. Isolates from the NA2 and EU1 lineages were the most aggressive and isolates from the NA1 group were the least aggressive. The NA1 lineage of P. ramorum was the most variable in aggressiveness and growth rate. The variability in the NA1 lineage was due to the presence of non-wild type (nwt) isolates. There was no significant difference in growth rate among NA1 wild type (wt), NA2, and EU1 lineages at any temperature tested. The difference between wt and nwt P. ramorum isolates is discussed.

1 aElliott, M1 aSumampong, G1 aVarga, A1 aShamoun, S F1 aJames, D1 aMasri, S1 aGrünwald, N J uhttp://dx.doi.org/10.1111/j.1439-0329.2009.00627.x