The
BC1´
-
peruvianum
line
failed
to
set
viable
seeds
when
crossed
to
tomato
as
male
or
female
parent
(Table
1),
but
plants
could
be
recovered
with
the
aid
of
immature
embryo
culture
in
one
cross
direction
.
More
relaxed
crossability
barriers
occurred
in
crosses
with
the
three
L
.
peruvianum
accessions
as
male
parents,
and
more
than
20
seeds
per
fruit
could
be
recovered
.
In
conclusion,
these
three
potential
bridge
lines
(the
two
“Marañon”
races
and
the
BC1´
-
peruvianum
)
do
not
appear
to
provide
an
effective
mean
for
overcoming
crossability
barriers
within
the
Lycopersicon
genus,
and
only
could
be
used
in
combination
with
embryo
rescue
techniques
.
These
results
do
not
support
Poysa's
(1990)
suggestion
that
the
ideal
bridge
lines
should
be
composed
of
75%
L
.
peruvianum
genome
.
The
BC1´
-
chilense
line
exhibited
unilateral
incompatibility
in
crosses
to
tomato
as
female
parent
(Table
1),
but
it
set
at
least
0
.
4
viable
seed/fruit
when
crossed
to
tomato
as
male
parent
.
Viable
seeds
per
fruit
ranged
from
3
.
5
to
28
in
crosses
with
the
3
L
.
peruvianum
accessions
.
This
line
has
the
same
percentage
of
wild
genome
as
BC1´
-
peruvianum
,
but
its
crossability
to
L
.
esculentum
is
significantly
higher,
probably
due
to
the
lower
degree
of
incompatibility
to
the
accession
L
.
chilense
LA
1932
to
L
.
esculentum
when
compared
with
most
L
.
peruvianum
accessions
.
This
behavior,
along
with
the
good
level
of
success
of
BC1´
-
chilense
in
crosses
with
accessions
highly
incompatible
to
tomato,
such
as
L
.
peruvianum
PI
-
126944
and
L
.
peruvianum
PI
-
126935
(both
resistant
to
TSWV
and
TYLCV),
makes
this
line
appropriate
as
a
bridge
to
introgress
these
and
other
peruvianum
traits
into
the
esculentum
genome
.
Literature
cited:
Ayuso,
M
.
C
.
,
Báguena,
M
.
,
Cuartero,
J
.
,
Nuez,
F
.
1987
.
Possibilities
of
using
the
compatible
form
L
.
peruvianum
PE
-
23
as
a
genetic
bridge
in
tomato
breeding
.
TGC
Report
37:
36
-
37
.
Gradziel,
T
.
M
.
,
Robinson,
R
.
W
.
1991
.
Overcoming
unilateral
breeding
barriers
between
Lycopersicon
peruvianum
and
cultivated
tomato,
L
.
esculentum
.
Euphytica
54:
1
-
9
.
Poysa,
V
.
1990
.
The
development
of
bridge
lines
for
interspecific
gene
transfer
between
Lycopersicon
esculentum
and
L
.
peruvianum
.
Theoretical
and
Applied
Genetics
79:
187
-
192
.
Rick,
C
.
M
.
1983
.
Crossability
between
L
.
esculentum
and
a
new
race
of
L
.
peruvianum
.
TGC
Report
33:
13
.
Taylor,
I
.
B
.
1986
.
Biosystematics
of
tomato
.
In:
Atherton,
J
.
G
.
,
Rudich,
J
.
(eds
.
)
.
The
tomato
crop:
A
scientific
basis
for
improvement
.
Chapman
and
Hall,
New
York,
pp
.
1
-
34
.
Taylor,
I
.
B
.
,
Al
-
Kummer,
M
.
K
.
1982
.
The
formation
of
complex
hybrids
between
Lycopersicon
esculentum
and
L
.
peruvianum
and
their
potential
use
in
promoting