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8. MOLECULAR PHYLOGENY OF THE GENUS LOLIUM
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the genus Lolium (Figure 8.11). It was also possible to calculate the values of Nei’s genetic
similarities summarized all over different genomic sequences (Table 8.3). It was likely that
genetic similarities averaged for different sequences emphasized the genome diversities
better because all types of sequences, from repetitive to low copy genes, from clustered
to randomly distributed were sampled. Expectedly, the highest Nei’s genetic similarity was
between two L. perenne subspecies while the lowest between Loliums and F. pratensis or
P. pratensis.
The consensus tree gave the strong support for the existence of two clades that probably
mirrored the evolutionary history of the genus. Unquestionable, three self-pollinated
species, L. temulentum, L. remotum and L. persicum constituted the first clade further assigned
as Temulentum clade. Within this group, L. temulentum and L. remotum were
most alike, however the intermediate I value (0.682) suggested the relatively recent split
between them. This clade was clearly distinct from the second cluster as well as from
F. pratensis, joining with them at I=0.398 and 0.345, respectively. It indicated a significant
degree of differentiation. The second clade further assigned as Perenne clade included four
species, the most similar L. perenne ssp. multiflorum and L. perenne ssp. perenne (I=0.935)
that joined with L. loliaceum. The similarity of 0.613-0.635 between L. loliaceum and
L. perenne justified the recent origin of these taxa, but they appeared well separated. All three
species formed a clade with L. rigidum, joining together at I=0.580 supporting the view that
they are closely related, yet distinct species. The placement of L. loliaceum among outbreed-