19
RESEARCH
NOTES
TGC
REPORT
No
.
31,
1981
Taylor,
I
.
B
.
Mapping
the
ls
locus
.
According
to
the
most
recent
linkage
summary
(TGC
30)
the
ls
locus
has
been
placed
at
position
132
of
chromosome
4
.
For
a
number
of
reasons
I
wanted
to
combine
ls
and
flc
to
form
a
double
homozygote
.
I
have
been
unable
to
detect
any
ls
ls
flc
flc
individuals
in
the
F
2
and
suggest
that
these
two
gene
loci
should
be
allocated
to
the
same
map
position
.
There
are
no
marker
genes
within
43
map
units
of
the
suspected
ls
site
on
chromosome
4
.
In
contrast,
the
presence
of
an
incompletely
dominant
marker,
La,
only
11
map
units
away
from
the
suspected
flc
site
on
chromosome
7,
provides
a
means
of
testing
the
suggestion
that
both
ls
and
flc
should
be
placed
on
this
chromosome
at
position
59
.
As
La
is
semi
-
lethal
in
the
homozygous
state,
these
genotypes
have
been
excluded
from
the
following
F
2
segregation
data
from
La/flc
and
La/ls
crosses
.
The
predicted
result
from
the
TGC
30
map
would
be
no
linkage
between
La
and
ls
.
This
assumption
does
not
fit
the
observed
data
and
gives
a
χ
2
of
137
.
41
.
By
assuming
that
ls
is
located
next
to
the
flc
locus
(position
59,
chromosome
7)
and
would
therefore
have
an
11%
recombination
frequency
in
crosses
with
La,
a
much
better
fit
is
obtained
(
χ
2
=
4
.
34)
.
The
F
2
for
the
La
x
flc
crosses
confirms
that
these
two
loci
are
linked
and
can
realistically
be
assumed
to
be
11
map
units
apart
.
I
therefore
propose
that
the
linkage
map
be
amended
with
respect
to
the
ls
locus,
which
should
be
reassigned
to
the
same
position
as
flc
on
chromosome
7
.
Valkova
-
Achkova,
Z
.
and
V
.
Sotirova
Tri
-
genomic
hybrid
between
Lycopersicon
esculentum
Mill
.
,
L
.
chilense
Dun
.
and
L
.
peruvianum
var
.
humifusum
Mill
.
reproductive
relationships
and
resistance
to
Corynebacterium
michiganense
(Smith)
Jensen
.
Our
attempts
to
cross
L
.
esculentum
with
L
.
peruvianum
var
.
humifusum
by
means
of
embryo
culture,
hybridiza
-
tion
on
heteroploid
level
and
other
methods
gave
no
result
.
The
reproductive
barriers
between
the
two
species
have
been
overcome
through
bridge
hybridization
.
The
F
1
plants
of
the
combination
L
.
esculentum
(isogenic
line
gf)
x
L
.
chilense
were
used
as
intermediaries
.
After
pollination
of
these
plants
with
pollen
of
L
.
peruvianum
var
.
humifusum,
four
seeds
were
obtained
and
gave
rise
to
F
1
plants
of
the
trigenomic
