With the help of 21 putative isoenzyme loci, the genetic diversity and variations of <em>Viscum album</em> ssp. <em>album</em> L. from 42 species, subspecies, varieties and hybrids of broadleaf trees, <em>Viscum album</em> ssp. <em>austriacum</em> (Wiesb.) Vollmann, from 4 populations of Scots pine (<em>Pinus sylvestris</em> L.) and <em>Viscum album</em> ssp. <em>abietis</em> (Wiesb.) Abromeit, from 8 populations of European silver fir (<em>Abies alba</em> Mill.) were analyzed. On the dendrogram, the three investigated subspecies form three clusters, each clearly separated from the other, so we suggest a revision of the systematic nomenclature proposed to take into consideration a return to an earlier system of dividing the European mistletoe into three species: <em>Viscum album</em> L., <em>Viscum abietis</em> Beck, and <em>Viscum laxum</em> Boiss. et Reut. From among the 21 tested loci only one locus, SOD-A, was monomorphic. The average number of actual alleles (Na) and effective alleles (Ne) was 2.23 and 1.61 respectively. The observed heterozygosity (Ho) varied from 0.199 in <em>V. album</em> ssp. <em>abietis</em> to 0.345 in the <em>V.a.</em> ssp. <em>album</em> populations. Average FST = 0.277 indicates that about 28% of genetic differentiation is due to an interpopulation diversity of <em>Viscum album</em> populations. There is a small gene flux between <em>Viscum album</em> populations with only one immigrant successfully entering a population per two generations (Nm = 0,653).
Relationship and genetic diversity of mistletoe (Viscum album L.) subspecies