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4. GENETIC DIVERSITY...
4.5. CONCLUSIONS
1. Genetic variation of L. multiflorum and L. perenne is high and typical of crosspollinated
species.
2. Surveys of the majority of marker analysed reveal nearly the same level of polymorphism
in L. multiflorum and L. perenne as estimated from the overall proportion
of polymorphic loci, mean number of alleles and the values of genetic diversity. The
markers specific to a species are hardly found with the only exception of few bands
revealed by SSAP.
3. The high differentiation of populations as measured by G ST
results from historical
processes such as colonisation after the last glaciation and spread of agriculture
as well as from intensive breeding. The populations in different regions may show
different evolutionary trajectories.
4. No erosion of genetic resources in relation to breeding activities is observed in
cultivars of L. multiflorum and L. perenne. However, the introgressions from closely
related genera (Festuca) may be responsible for some distinctiveness of L. multiflorum
cultivars.
5. High molecular similarity strongly supports the classification of L. multiflorum and
L. perenne as a single species. Nevertheless, some mechanisms of “sudden speciation”
can not be excluded prior to detail mapping studies.
6. Both DNA transposons and retrotransposons have been playing important role in
L. multiflorum and L. perenne evolution. It is likely that L. perenne is more ancient
than L. multiflorum but detailed phylogenesis can be clarified in a study involving
the members of the whole genus and closely related genera.
7. The higher activity of transposons in L. multiflorum suggests further diversification
of both species. The adaptation to more diverse environments and breeding activities
will promote this process.