2.1.3. Case study 3: dynamics of genetic structures in
juvenile beech (F. sylvatica L.)
The experiments described in case study 2 as well as
earlier observation by Mu¨ller-Starck (1993) and Kim
(1985) led to similar conclusions about the relevance
of heterozygosity. Pre-germinated beech nuts with a
large degree of heterozygosity at enzyme gene loci
proved to possess also larger viability to reach the
juvenile stage, if the material was raised under field
conditions. With standard garden soil in the greenhouse,
the opposite effect was established: seed material
with lower degree of heterozygosity appeared to
be superior (compare Fig. 2). Here temporarily heterogeneous
environmental conditions obviously favor
superior survival of heterozygotes; homozygosity is
supported by relatively homogeneous conditions