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8. MOLECULAR PHYLOGENY OF THE GENUS LOLIUM
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2003). From a practical point of view, this rate heterogeneity is highly beneficial by permitting
for each kind of phylogenetic analyses from the population to higher taxa level. For example,
the slowly evolving sequences are informative in reconstructing deep branches, while rapidly
evolving sequences are especially useful in intraspecific analyses. The major strength of
multi-character molecular approaches is that, unlike many morphological traits, the assumption
of independence is probably valid. In any approach, molecular data are also well suited
for constructing phylogenetic trees. With growing number of taxa surveyed at molecular level
both phenetic and cladistic appraisals are important in resolving branch topology. With regard
to Lolium a sad truth is that DNA assays have rarely been used to resolve evolutionary
relationships within the genus. This is in spite of its economic importance, plenty of sophisticated
analyses for L. perenne ssp. perenne and close relationships with cereals from which
analytical procedures can be transferred easily. After all breeding strategies can often benefit
from knowledge about evolutionary relationships of crops. A case in point involves management
strategies aimed at conservation of turf characters in perenne and protection from
undesired gene flow from multiflorum as well as introgression of advantageous genes from
other members of the genus or closely related genera. The additional reason for phylogenetic
studies is that they are guides to predicting risks of unwanted gene flow from improved transgenic
grasses that are in the centre of attention of breeding companies (Yamada et al. 2005).
Multiple molecular assays used in the preceding chapters have illustrated well how useful
they can be in resolving species phylogenies within the genus Lolium. A lesson learnt from
L. perenne is that its domestication resulting in differentiation into two subspecies, wild perenne
and domesticated multiflorum has lasted only hundreds of years. Thereby the next
arising question is whether L. perenne is separated from another allogamous species
L. rigidum or they should be also joined into a single species as Bulińska-Radomska and
Lester (1985) proposed If not when did they diverge What are the relationships within
allo- and autogamous species Do they really represent different evolutionary lines as it has
been shown by katG markers (Polok 2005) or perhaps the whole genus should be treated
as a single entity Answering at least some of these questions was the goal of this part of
research. With the vast molecular methods in hands and with data gathered during the studies
on multiflorum and perenne the attempts were undertaken to reconstruct the phylogenetic
relationships within the genus Lolium.
8.2. MATERIAL AND METHODS
All species belonging to the genus Lolium were analysed i.e., four autogamous species,
L. loliaceum, L. persicum, L. remotum, and L. temulentum as well as two allogamous species,
L. perenne with two subspecies L. perenne ssp. perenne and L. perenne ssp. multiflorum,
and L. rigidum. In a case of multiflorum and perenne the bulk sample was made from
all genotypes used in the genetic diversity studies. Moreover, the parental genotypes from
genome mapping were used as a control to facilitate the identification of mapped markers.
Endemic to the Canary Islands, L. canariense was not included owing to difficulties in obtaining
sufficient number of viable seeds from gene banks. To facilitate tree rooting and help to
establish character-state polarities Festuca pratensis and Poa pratensis were included as