Development
of
Interspecific
Hybrids
between
Lycopersicon
esculentum
and
L
.
peruvianum
var
.
humifusum
and
Introgression
of
Wild
Type
Invertase
Gene
into
L
.
esculentum
.
Imanishi,
S
.
1
,
Egashira,
H
.
1
,
Tanaka,
H
.
1
,
Harada,
S
.
2
,
Takahashi,
S
.
1
,
Nishizawa,
T
.
1
,
Nishimura,
R
.
1
,
Takashina,
Z
.
1
1
University
of
Yamagata,
Fac
.
Agric
.
1
-
23,
Wakaba
-
cho,
Tsuruoka
997,
Japan
2
Kagome
Co
.
,
Ltd
.
,
Research
Institute,
Nishinasuno,
Nasu
329
-
27,
Japan
The
strictest
barriers
hamper
the
development
of
the
hybrid
embryos
of
L
esculentum
and
L
.
peruvianum
var
.
humifusum
.
This
study
was
carried
out
in
order
to
produce
interspecifc
hybrids
and
their
backcross
progenies
using
the
ovule
selection
method
(Imanishi
et
al
.
,
1985;
Imanishi
et
al
.
,
1993)
.
Twenty
-
three
hybrid
plants
(F,)
were
obtained
from
67
fruits
(Table
1)
.
These
F,
plants
were
confirmed
by
the
morphological
and
physiological
resemblance
of
their
traits
(prostrate
habit,
slender
stem,
tiny
leaf
segment,
high
levels
of
anthocyanin,
and
the
scent
of
Japanese
pepper)
to
those
of
the
pollen
parent,
L
.
peruvianum
var
.
humifusum
LA2153
.
The
first
backcross
progeny
(B1F1)
obtained
were
9
plants
from
61
fruits
.
Many
plants
of
the
second
backcross
progeny
(B
2
F
1
)
were
produced,
of
which
70%
were
self
-
compatible
.
Fruit
weight
and
seeds
per
fruit
of
the
B
2
F
1
,
indicated
that
their
traits
were
beginning
to
match
those
of
the
L
.
esculentum
.
Table
1
.
Ovule
culture
for
the
development
of
the
F
1
,
B
1
F
1
,
and
B
2
F
1
,
generations
in
the
Interspecific
hybridization
of
L
.
esculentum
and
L
peruvianum
var
.
humifusum
.
EP:
Lycopersicon
esculentum
c
.
v
.
'EarlyPink'
LA2153:
L
peruvianum
var
.
humifusum
1
The
rest
of
the
ovules
which
did
not
germinate
were
dissected
for
the
embryo
culture
which
recovered
a
number
of
B
2
F
1
,
plants
.
PCR
-
diagnosis
of
the
tomato
acid
invertase
gene
was
performed
by
using
one
pair
of
primers
(Harda
et
al
.
,
1995)
in
order
to
confirm
the
introgression
of
the
L
.
peruvianum
type
invertase
gene
into
the
B2F2
population
.
Twenty
-
three
lines
out
of
a
total
of
28
lines
that
were
examined
were
found
to
be
homozygous
for
the
L
.
esculentum
type
gene
(Table
2)
.
The
remaining
five
lines
were
found
to
be
of
mixed
types,
including
the
homozygous
L
.
esculentum
type,
the
homozygous
L
.
peruvianum
type,
and
the
F
1
type
gene
plants
.
Seven
homozygous
L
peruvianum
type
gene
plants
were
selected
out
of
a
total
of
263
B
2
F
2
plants
.
The
content
of
sucrose
and
hexoses
of
fruits
was
determined
for
each
of
the
invertase
-
genotypes
.
The
fruits
of
the
homozygous
L
.
esculentum
type
and
the
F
1
type
plants
accumulated
mainly
hexoses,
glucose
and
fructose,
while
the
homozygous
L
peruvianum
type
plants
accumulated
soluble
sugars
in
the
fruit
primarily
as
sucrose
(Fig
.
1)
.
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