35
The
determined
frequency
and
distribution
of
chiasmata
in
L
.
pimpinellifolium
and
its
autotetraploid
are
as
follows:
Table
2
.
Chiasmata
frequency
in
L
.
pimpinellifolium
and
its
autotetraploid
Object
Chiasmata
frequency
per
whole
genome
Distal
chiasmata
frequency
Interstitial
chiasmata
frequency
L
.
pimpinellifolium
2n=48
32
.
6
±
0
.
4
29
.
05
±
0
.
46
3
.
55
±
0
.
23
L
.
pimpinellifolium
2n=24
19
.
87
±
0
.
18
16
.
14
±
0
.
22
3
.
75
±
0
.
11
The
number
of
chiasmata
increased,
with
a
change
from
di
-
to
tetraploid,
as
little
as
by
64%,
number
of
distal
chiasmata
—
by
81%,
as
long
as
the
number
of
interstitial
chiasmata
remained
generally
the
same;
that
means
that
the
chiasmata
frequency
calculated
per
bivalent
decreased
.
The
frequency
of
distal
chiasmata
per
bivalent
decreased
by
two
times,
and
the
distal
location
of
the
major
part
of
the
chiasmata
(i
.
e
.
,
of
cross
-
overs)
results
in
the
tendency
that
all
genes
located
in
the
middle
part
of
the
chromosome
keep
the
initial
order
and
thus
behave,
to
a
certain
extent,
as
a
supergene
.
Thus,
the
twofold
increase
in
the
number
of
chromosomes
in
tomato
leads
to
a
change
in
the
general
level
of
crossing
-
over
and
to
redistribution
of
exchanges
along
the
chromosome
and
generally,
to
the
decrease
in
number
of
crossing
-
overs
and
a
rapid
decrease
in
the
number
of
interstitial
chiasmata
per
bivalent
.
Literature
cited:
MacCollum
G
.
D
.
(1958)
.
Comparative
studies
of
chromosome
pairing
in
natural
and
induced
tetraploid
Dactylis
.
Chromosoma,
9,
571
-
605
.
Zhuchenko
A
.
A
(1988)
Adaptive
potential
of
cultivated
plants
(genetic
and
ecological
bases)
.
Cisinau,
''Shtiinza'',
768pp
.
Wallace
A
.
J
.
and
Callow
R
.
S
.
(1995)
.
Meiotic
variation
in
an
intergenomic
autopolyploid
series
.
I
.
Chiasmata
frequency
.
Genome,
38,
1,
122
-
131
.
