TGC
REPORT
No
.
31,
1981
RESEARCH
NOTES
16
exchanges
per
set
was
noticed
.
However,
a
vast
majority
of
pachytene
trivalents
showed
only
one
exchange
of
partners
.
The
reduction
in
homologies
between
chromosomes
of
the
two
species
might
be
to
some
extent
responsible
for
the
lower
multivalent
formation
at
diakinesis
which
is
a
manifestation
of
fewer
partner
exchanges
at
pachytene
.
Since
this
is
an
inter
-
specific
hybrid
where
one
of
the
parents
is
an
autotetraploid
and
the
other
a
basic
diploid
of
another
species,
the
chromosomes
of
the
latter
species
may
not
be
completely
homologous
to
those
of
the
former
.
Thus,
because
of
the
incomplete
homologies,
at
least
for
some
of
the
chromosomes,
in
certain
segments,
some
inhibition
for
formation
of
partner
exchanges
in
these
segments
might
have
occurred
resulting
in
a
reduced
frequency
of
exchanges
.
This
might
be
the
reason
for
the
reduction
in
number
of
double
exchanges
as
well
as
the
low
frequency
of
exchanges
in
long
arm
euchromatin
of
chromosomes
5
and
7
compared
to
short
arm
euchromatin
.
In
view
of
the
incomplete
homologies
between
chromosomes
of
the
two
species,
the
pairing
behavior
in
this
sesquidiploid
with
regard
to
occurrence
and
distribution
of
partner
exchanges
might
be
different
from
that
expected
in
an
autotriploid,
where
the
three
chromosomes
in
each
set
are
completely
homologous
.
Rick,
C
.
M
.
and
M
.
Holle
Wild
and
feral
A
project
designed
for
collecting
species
in
southern
Ecuador
and
Peru
.
tomato
species
in
southern
Ecuador
and
northern
Peru
was
undertaken
in
August
-
October
1980
.
The
project
was
supported
by
IBPGR/FAO
.
The
purpose
was
to
make
observations
in
the
native
habitats
and
sample
germplasm
of
Lycopersicon
and
closely
related
Solanum,
species
in
a
region
that
has
been
searched
to
a
limited
extent
previously
and
whose
tomato
species
reserves
were
to
a
large
extent
unknown
.
The
trip
to
Ecuador
was
made
in
August
throughout
the
Province
of
Loja,
adjacent
parts
of
Zamora
-
Chinchipe,
and
western
Morona
-
Santiago
.
The
dominant
species
throughout
most
of
this
area
is
L
.
hirsutum
f
.
glabratum
.
We
