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3. MORPHOLOGICAL VARIATION...
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than Lolium, fescues are generally more persistent and can tolerate more extreme abiotic
stresses (Humphreys et al. 2003). Several traits have been reported to be transferred from
F. pratensis to L. multiflorum. An example is resistance to the leaf fungal disease Puccinia
coronata Corda (crown rust). The morphology of most resistant plants resembled L. multiflorum
completely although very occasionally single spikes were branched (Oertel and Matzk
1999). Another approach employs introgression from hexaploid Festuca species either from
F. arundinacea or F. gigantea. Because resultant tetraploid F 1
hybrids have low fertility, the
pentaploid hybrids are produced by crossing autotetraploid L. multiflorum and hexaploid
F. gigantea (or arundinacea). After 2-3 backcrosses diploid hybrids are recovered. They are
morphologically and developmentally like L. multiflorum but they do show some Festuca
characters. Pentaploids hybrids are now used frequently as the starting point of introgression
breeding programmes aimed at the transfer of useful characters into Italian ryegrass
(Humphreys et al. 2003).
The separation of L. multiflorum and L. perenne into two species does not appear to be
justified following the results of this study. The anticipated complexity of multifunctional grasslands
and sustainable management practices demands the broad gene pools with options
to combine complementary traits. Traditional approaches based on within-species variation
are unlikely to achieve such objectives. New techniques in introgression of Festuca genes
into Lolium have been more and more popular. They will inevitable lead to the diversification
of Italian and perennial ryegrass cultivars and furthermore may result in species diversification.
To conclude, however, the morphology alone although helpful is not enough to decide if
L. multiflorum and L. perenne are separated or not. Biological species are defined by different
gene pools and therefore, evidences showing whether both species have the same gene
pool can confirm the above hypothesis.
3.5. CONCLUSIONS
1. The morphological analysis does not confirm the separation of L. multiflorum and L. perenne
into two species. They are similar in the majority of studied characters, the range
of variation overlaps and mean values are very alike.
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2. The separation is possible only based on the 1 year flowering and recovery after winter
although variation of both characters is present and can be connected with geographic
origin and breeding activities.
3. The separate position of L. multiflorum cultivars results from breeding activities. Ecotypes
of both species do not differ providing the evidence that differentiation of L. multiflorum
and L. perenne is rather caused by human activities than evolutionary processes.