Allozyme Differentiation of the Silver fir in the West-East Direction as a Consequence of the Postglacial Migration : Gemeinsame Jahrestagung

1994

1 S.

Serie

400089912

Samples of buds in winter-dormancy from 8 silver fir provenances were analysed electrophoretically at the enzyme loci Idh-1, Idh-2, 6-Pgdh-2 and Lap-1. The enzyme data indicate a clear differentiation into two distinct clusters: a western group comprising the provenances from Vorarlberg and Tirol, and an eastern group with provenances from Carinthia, Styria, Upper- and Lower Austria. In the regions Vorarlberg and Tirol samples were taken from both low (<900m) and high (>900m) altitudes, but no differentiation depending from altitude was observed. The distribution of genotypes was in accordance with Hardy-Weinberg expectations. With exception of 6-Pgdh-2, frequency clines were detected in west-east direction. These clines can be explained as a result of selection and drift in the course of the postlacial migration fr a refuge in Central Italy. In addition to the 8 provenances mixed seed samples from 4 stands in south-easter Styria were analysed. One of these samples proved different with respect to the locus 6-Pgdh-2. Whereas 6-Pgdh-2 was found monomorphic in the other populations, seeds from this particular stand harboured a rare allele, characteristic for provenances originating from a Balkan refuge. From this stand allele frequencies at the loci Idh-2 and Lap-1 were also significantly different from samples taken in the adjacent area. Provided that this exeptional stand is autochthonous, gene flow from the Balkans to the south-eastern part of Austria seems likely.