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4. GENETIC DIVERSITY...
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4.3.3. Genetic similarity of L. multiflorum and L. perenne
Estimates of Nei’s genetic identities between L. multiflorum and L. perenne were very
high (Table 4.6), well within the range of values normally associated with conspecific populations.
The highest value was obtained for enzymatic loci (0.986). The analysis of random and
semi-random nuclear DNA markers revealed only slightly lower values ranging from 0.925
for RAPDs to 0.976 for ISJs. It is not a surprise that the highest degree of differentiation was
observed for insertional polymorphism but still the values were much higher than for distinct
species (0.887-40.896).
The similarities between ecotypes and cultivars within each species were high
(0.821-0.999) although the degree of differentiation did not differ from that for interspecific
comparisons (0.783-0.999). The only exception was the higher similarity of transposons
within a species. The Nei’s coefficients for within species comparisons ranged from
0.848 to 0.950 whereas genetic similarities between species ranged from 0.783 to 0.871.
Surprisingly, cultivars of L. multiflorum were quite different from ecotypes while estimating
from RAPDs (I=0.821) and ISJs (I=0.867). Such a relationship was not observed in
L. perenne thus, suggesting different breeding strategies in both species (Table 4.7).
When we instead turn to interspecific comparisons, ecotypes were more similar than
cultivars, again indicating the influence of breeding activities on species differentiation. In
some cases, the Nei’s coefficients for ecotypes were even higher than for within-species
comparisons (Table 4.7). For example mtDNA of Italian and perennial ryegrass was more
similar (0.999) than mtDNA of cultivars and ecotypes within L. multiflorum (0.907). What is
more, the cultivars of L. multiflorum appeared to be closer related with L. perenne ecotypes