Mapping
and
introgression
of
a
quantitative
trait
loci
(QTL)
for
reduced
stem
scar
size
from
Lycopersicon
pimpinellifolium
Doganlar,
S
.
and
Tanksley,
S
.
D
.
Stem
scar
size,
attachment
site
of
fruit
to
the
stem,
is
an
important
characteristic
for
both
processing
-
and
fresh
market
-
type
tomatoes
.
In
processing
-
type
varieties,
a
small
stem
scar
size
is
desirable
because
fruit
with
small
stem
scars
usually
release
better
during
harvest
and
peel
more
easily
with
less
waste
during
processing
.
In
addition,
large
stem
scars
may
penetrate
into
the
fruit
and
be
visible
as
a
"yellow
eye"
if
the
processed
peeled
fruit
is
whole
or
diced
.
However,
varieties
with
very
small
stem
scars
are
undesirable
because
the
fruit
may
fall
off
the
plant
prematurely
during
mechanical
harvesting
.
For
fresh
market
tomatoes,
stem
scar
size
is
mainly
an
appearance
characteristic
.
When
a
line
having
large
stem
scars
is
crossed
with
a
line
with
small
stem
scars,
F1
hybrids
resemble
the
parent
with
small
stem
scars
on
the
fruits
.
Therefore,
it
has
been
concluded
that
enlarged
stem
scars
appeared
to
be
controlled
by
one
or
more
recessive
genes
.
In
this
study,
a
QTL
controlling
stem
scar
size
was
identified
in
a
population
of
216
BC2F4
lines
derived
from
a
cross
between
L
.
esculentum
cv
.
M82
x
L
.
pimpinellifolium
(LA1589)
.
Based
on
phenotypic
and
molecular
marker
analysis,
the
QTL
was
mapped
to
the
bottom
of
chromosome
8
between
CT265
and
CT68
.
As
further
confirmation,
59
BC2F5
lines
derived
from
BC2
plants
that
were
heterozygous
for
these
2
markers
were
selected
and
grown
in
the
greenhouse
.
Based
on
phenotypic
and
genotypic
(CT265
and
CT68)
analysis
of
these
59
plants,
CT265
showed
a
strong
association
(P<0
.
0001)
with
stem
scar
size
.
No
significant
association
was
seen
for
fruit
weight
.
Therefore,
CT265
can
be
used
for
marker
assisted
selection
for
reduced
stem
scars
without
sacrificing
fruit
weight
.
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