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4. GENETIC DIVERSITY...
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Organelle DNA polymorphism
Five restriction fragments were identified in psbC-trnS after HaeIII digestion. The
other two enzymes, DralI and EcoRI did not cut this chloroplast DNA fragment. A total
of 11 PCR products were observed after amplification of Lolium DNA with primers specific
to the intron between B and C exons in nad1 gene. Mitochondrial origin of revealed
fragments was proved in F 1
hybrid of a cross between L. multiflorum (Bartolini) and
L. perenne (ecotype from New Zealand) and 20 F 2
individuals. The female haplotype was distinguished
by the presence of six bands in comparison with ten in the male one. The F 1
hybrid
possessed all six bands typical of female parent and none of the male parent. Moreover, the
female haplotype was present in all 20 F 2
individuals.
The level of polymorphism was relatively low for organelle DNA in comparison with
enzymes and the nuclear DNA markers used (Table 4.1). Of the five fragments scored
from cpDNA, only two (40%) were polymorphic in L. multiflorum and three (60%) in
L. perenne. This resulted in as few as six haplotypes identified (Figure 4.2). The most frequent
were haplotypes n o 1 and n o 2, which were shared equally by both species (Table 4.3).
The rest haplotypes were rare, and nearly all were characteristic to L. perenne. Only the n o 4
was typical of L. multiflorum ecotype, Variamo (Table 4.4).
A slightly higher proportion of polymorphic bands was observed in mitochondrial DNA
of both species (72 and 63%). The values in cultivars and ecotypes were quite similar (Table
4.1). In contrast to cpDNA more than doubled number of haplotypes was produced (Figure
4.3). Only three of them were present both in L. multiflorum and L. perenne. The haplotype
n o 3 was observed with relatively high frequency in both species (0.250 and 0.334). It was
also equally frequent in cultivars and ecotypes (Table 4.3). In contrast, the other two shared
haplotypes (n o 4 and n o 11) were rare and specific to a population (Table 4.4). Each of them
was harboured by a single population per a species. The majority of mitochondrial haplotypes
(76%) were rare and specific not only to a species but also to a population. L. multiflorum
harboured the unique haplotypes n o 5, 8, 9, 10 and 13 whereas L. perenne - n o 1, 2, 6, 7
and 12. If we considered populations studied, the most distinct was ecotype from the Tatras
because it harboured both cpDNA and mtDNA haplotypes not present anywhere else.