A
tentative
study
of
some
Solanum
relatives
for
disease
resistance
Stamova,
L
.
,
and
Chetelat,
R
.
T
.
Dept
Vegetable
Crops,
Univ
.
Calif
.
Davis
CA
95616
For
some
tomato
diseases,
no
resistance
is
known,
and
for
others
resistance
genes
are
ineffective
against
some
pathogen
strains
.
This
situation
led
us
to
search
for
resistance
in
some
genetically
distant
wild
relatives,
even
if
for
the
present
they
cannot
be
directly
hybridized
with
the
cultivated
tomato
.
During
the
author's
visit
in
the
C
.
M
.
Rick
TGRC
in
UC
-
Davis,
the
following
species
have
been
screened
for
resistance
to
some
diseases:
S
.
sitiens
(accessions
LA1974,
LA2876,
LA2877,
LA2878,
LA2885),
S
.
ochrantum
(LA2165,
LA2682)
and
S
.
juglandifolium
(LA2134,
LA2788)
.
All
of
the
above
mentioned
species
were
inoculated
with
a
fern
strain
of
cucumber
mosaic
virus
(CMV)
.
Plants
of
the
susceptible
cvs
VF36
and
Vendor
-
Tm2
a
showed
heavy
mosaic
and
shoe
-
string
leaves,
whereas
no
CMV
symptoms
were
registered
in
S
.
ochrantum
and
S
.
juglandifolium
accessions
after
inoculation
.
The
same
reactions
were
shown
after
inoculation
with
tomato
spotted
wilt
virus
(TSWV)
.
Some
of
the
S
.
sitiens
were
found
to
segregate
for
resistance
to
CMV
in
respect
to
stunting
of
the
plants
after
inoculation
.
S
.
sitiens
(LA1974)
was
uniformly
susceptible
after
inoculation
with
3
isolates
of
Botrytis
cinerea
from
tomato,
grape,
and
apple
.
In
the
same
greenhouse
as
these
tests,
a
heavy
natural
infection
was
observed
for
an
Oidium
powdery
mildew,
apparently
new
for
California
.
All
of
the
aforementioned
Solanum
spp
.
showed
resistance,
and
simultaneously
the
nearby
normal
cultivars
suffered
sporulation
on
leaves,
petioles
and
stems
.
Identification
of
co
-
dominant
RAPD
markers
tightly
linked
to
the
tomato
spotted
wilt
virus
(TSWV)
resistance
gene
Sw
-
5
.
Stevens,
M
.
R
.
,
Heiny,
D
.
K
.
1
,
Griffiths,
P
.
D
.
2
,
Scott,
J
.
W
.
2
,
and
Rhoads,
D
.
D
1
.
Dept
.
of
Agron
.
&
Hort
.
,
Brigham
Young
Univ
.
,
Provo,
UT
84602
'Dept
.
of
Biol
.
Sci
.
,
Univ
.
of
Ark
.
,
Fayetteville,
AR
72701
Gulf
Coast
Res
.
&
Edu
.
Center,
IFAS,
Univ
.
of
Fla
.
,
60th
St
.
E
.
,
Bradenton,
FL
34203
The
tomato
(Lycopersicon
esculentum)
cultivar
'Stevens'
contains
a
single
dominant
gene
(Sw
-
5)
(Stevens
et
al
.
1992)
originating
from
L
.
peruvianum
(van
Zijl
et
al
.
1986)
which
confers
resistance
to
tomato
chlorotic
spot
virus
(TCSV),
ground
ring
spot
virus
(GRSV)
and
common
strains
of
TSWV
(Boiteux
and
Giordano
1993)
.
Restriction
fragment
length
polymorphism
(RFLP)
analyses
position
Sw
-
5
on
the
long
arm
of
chromosome
9
in
the
sub
-
telomeric
region
between
CT71
and
CT220
(Stevens,
1993;
Stevens
et
al
.
,
1995)
.
We
identified
a
randomly
amplified
polymorphic
DNA
(RAPD)
primer
(UBC
primer
#72
[GAG
CAC
GGG
A])
