conjugation
and
the
absence
of
uni
-
and
polyvalents
were
observed
.
The
frequency
of
the
distal
chiasmata
by
five
or
more
times
exceeds
the
frequency
of
interstitial
ones
.
2
.
The
analogous
investigations
concerning
the
second,
well
discernible
pair
of
chromosomes
were
performed
.
In
respect
to
this
a
substantial
difference
in
the
chiasmata
frequency
was
observed
between
the
second
cluster
and
the
others
.
At
the
2nd
cluster,
the
chiasmata
frequency
(2nd
chr
.
)
is
the
least
of
all
and
amounts
to
1
.
29
±
0
.
073
.
Likewise,
the
distal
chiasmata
frequency
is
significantly
lower
at
the
2nd
cluster
.
The
frequency
of
interstitial
chiasmata
at
the
2nd
pair
of
chromosomes
does
not
differ
with
the
growth
of
number
of
cluster,
and
every
time
exceeds
the
frequency
of
distal
ones
.
In
addition,
interstitial
chiasmata
at
the
second
pair
accounts
for
1/3
of
the
total
number
of
interstitial
chromosomes
in
a
cell,
i
.
e
.
per
12
II
.
This
shows
that
particular
chromosomes
may
have
individual
peculiarities
in
their
chiasmata
distribution
.
3
.
We
also
compared
chiasmata
frequencies
between
L
.
pimpinellifolium
plants
of
the
1st
and
2nd
years
of
life
.
For
the
purpose
of
purity
of
experiment,
the
bud
fixations
were
performed
simultaneously
.
Eventually,
significant
differences
between
the
plants
were
not
obtained
either
in
the
amount
and
distribution
of
the
total
chiasmata
or
at
the
bivalent
formed
by
the
2nd
chromosome
.
From
the
above
-
stated
results
one
can
conclude
the
following
statements
.
The
total
chiasmata
frequency
remains
unperturbed
during
the
entire
period
of
vegetation
.
The
distribution
of
chiasmata
over
locations
at
a
bivalent,
both
totally
and
particularly
at
the
2nd
pair
of
chromosomes,
does
not
demonstrate
any
explicit
dependence
on
age
.
The
changes
in
the
frequencies
of
distal
and
interstitial
chiasmata
most
likely
should
be
ascribed
to
external
factors
.
All
the
above
-
mentioned
facts
show
the
necessity
of
the
use
of
cytological
analysis,
along
with
hybridological,
for
the
purpose
of
more
profound
penetration
into
the
specifics
of
the
formation
of
recombinational
variability
.
Literature
cited:
Vysotskaya
LV
(1995)
Chiasmata
terminalization
.
The
analysis
of
the
phenomenon
.
(in
Russian)
Genetika
31:637
–
645
Griffing
B
and
Langridge
J
(1963)
Factors
affecting
crossing
-
over
in
the
tomato
.
Austral
.
J
.
Biol
.
Sci
.
,
16:862
–
837
Zhuchenko
AA
and
Korol
AB
(1985)
The
recombination
in
evolution
and
selection
(in
Russian)
.
Nauka,
Moscow
.
400
pp
.
Zhuchenko
AA
jr
.
(1996)
Thes
.
Doct
.
,
VNIIR,
Russ
.
Acad
.
Sci,
Sanct
-
Petersburg
Turkov
VD,
Guzhov
YuL,
Shelepina
GA,
Kishmaria
YaSh,
and
Kometiani
DG
(1988)
Chromosomal
investigations
of
plants
in
problems
of
selection,
cell
engineering
and
in
genetic
monitoring
(in
Russian)
.
Izd
-
vo
Univ
.
Druzhby
Narodov,
Moscow
.
64
pp