RACE DIFFERENTIATION IN FUSARIUM OXYSPORUM F. SP. DIANTHI AND VARIETAL
SUSCEPTIBILITY ( ° )
A. Garibaldi
I s t i t u t o di Patologia vegetale
Torino
Italy
Abstract
Two races o f F u s a r i u m
o x y s p o r u m
f . sp.
d i a n t h i
are present i n almost equal r a t i o i n I t a l y : among the v a r i e t i e s
tested to race 1 are susceptible 7 "mediterranean" and 13 " m i n i a t u r e s " ,
to race 2 are susceptible a l l the 52 v a r i e t i e s belonging to "american",
"mediterranean" and " m i n i a t u r e " groups.
F u s a r i u m
w i l t , known to occur i n I t a l y from the beginning
of t h i s century (Cuboni, 1908),became recently one of the most
dangerous and severe diseases of carnation not only i n Northern I t a l y ,
but also i n new areas of production i n the South (Zanardi et a l . , 1971;
F r i s u l l o and P i g l i o n i c a , 1976). The control by steam s t e r i l i z a t i o n and
chemical fumigation i s not always completely successful! on commercial
holdings and, besides, i s very expensive. The use of systemic f u n g i cides i s less e f f e c t i v e than i n the case of
P h i a l o p h o r a
ci n e r e s c e n s
( G a r i b a l d i , 1970) and a complete f a i l u r e of
s o i l treatments w i t h benzimidazole d e r i v a t i v e s has been r e c e n t l y report
ed due to the presence of a s t r a i n of
F.
d i a n t h i
resistant
to these fungicides (Tramier and B e t t a c c h i n i , 1974). Only a l i t t l e
m i n o r i t y of carnation v a r i e t i e s shows resistance to the pathogen (Garibaldi and Pergola, 1975). The successfull t r a n s f e r by breeding of
resistance from these v a r i e t i e s to more desirable agronomic l i n e s of
carnation l a r g e l y depends con race composition of
F u s a r i u m
o x y s p o r u m
f . sp.
d i a n t h i .
In t h i s paper we describe some of the r e s u l t s of the t r i a l s c a r r i e d
out from 1971 to 1975 at the I s t i t u t o di Patologia vegetale of Turin
with the aim o f :
1) studying physiologic s p e c i a l i z a t i o n w i t h i n
s p o r u m
f . sp.
d i a n t h i ;
F u s a r i u m
oxy
2) t e s t i n g a large number of carnation v a r i e t i e s belonging to the
"american" and "mediterranean" ecotypes and to the "miniature" group
f o r resistance to the two races of
F .
d i a n t h i ,
which
have been reported i n I t a l y ( G a r i b a l d i , 1975.
( ° ) Work supported by a grant of the National Research Council,
Acta Horticulturae 71, 1977
Carnations
Italy.
97
Materials and methods
The strains of
F u s a r i u m
o x y s p o r u m
f . sp.
d i a n t h i
used in t h i s work were i s o l a t e d from carnation plants
grown in I t a l y , France, and Spain (table 1). A l l cultures were singlespored, preserved on PDA at 3°C and subcultured at six months i n t e r v a l s .
New cultures were i n i t i a t e d from infected carnation stems at least once
during the work. A l l the experiments were carried out in a greenhouse
during the summer, under natural l i g h t , at 20-35°C, o r , during the.
other seasons, in a controlled temperature room under fluorescent l i g h t
/12 hr of l i g h t (1 000 foot candles) at 26°C, 12 hr of darkness at
23°C/. Carnation plants of each v a r i e t y were a r t i f i c i a l l y inoculated by
dipping t h e i r roots in a suspension of conidia ( l - 5 x l 0 ^ / m l ) and myceli a l fragments of each isolate of
F .
d i a n t h i
obtained by
grinding a 4 days old culture of the pathogen on casein hydrolisate
medium. To d i f f e r e n t i a t e the races, the f o l l o w i n g v a r i e t i e s were used:
"Arthur" and "Scania" (resistant to race 1 ) ; "Astor" and "Torino"
(susceptible to race 1). 10-25 plants of each v a r i e t y were inoculated
with every isolate and transplanted i n steam-sterilized s o i l .
The severity of the disease symptoms was rated on each plant at
d i f f e r e n t intervals of time a f t e r the appearance of the f i r s t symptoms
using a disease index from 0 (healthy plant) to 100 (dead p l a n t ) .
Results and discussion
Physiologic specialization
The race 1 of
F .
d i a n t h i
has been obtained not
only by "mediterranean" but also by "miniature" carnation v a r i e t i e s on
Riviera Ligure and in Spain (table 1). 13 (42%) of the strains isolated
in 1974, 1975, and 1976 can be referred to t h i s pathotype. On the
contrary, 18 (58%) of the isolates can be put in race 2: these have
been obtained from every group of v a r i e t i e s . Very recently, a t h i r d
pathogenic race has been isolated by a "Sim" v a r i e t y on Riviera Ligure;
t h i s race is v i r u l e n t on the "american" and not on some of the "meditej^
ranean" v a r i e t i e s . On t h i s race the investigations are s t i l l in progress
in order to investigate the d i f f u s i o n e and the s u s c e p t i b i l i t y of a large
number of v a r i e t i e s .
Varietal
susceptibility
Race 2 has been confirmed ( G a r i b a l d i , 1975) to be v i r u l e n t on
a l l the carnation
varieties tested belonging to every group of carnation
(table 2). Race 1, on the contrary, was f u l l y v i r u l e n t only on some of
the v a r i e t i e s belonging to the "mediterranean" ecotype and to the "minia
ture" group. More exactly, 7 of the 25 "mediterranean" and 13 of the 19
"miniature" varieties tested were susceptible to race 1.
98
References
Cuboni, G., 1908. Malattie di garofani prodotte da
F u s a r i um
d i a n t h i . Relazione sulle malattie delle piante studiate durali
te i l biennio 1906-07, Roma.
F r i s u l l o , s . , and P i g l i o n i c a , V., 1976. Malattie fungine presenti nelle colture di garofano del Salento e indicazioni sui mezzi di l o t t a .
1° Conv.Floricoltura Salento: 69-77.
Garibaldi, A., 1970. Impiego di sostanze ad azione endoterapica nella
l o t t a contro la f i a l o f o r o s i del garofano. A g r i c o l t . i t a l . 70: 226-235.
Garibaldi, A., 1975. Race d i f f e r e n t i a t i o n in
F u s a r i u m
oxys p o r u m f . sp.
d i a n t h i . F i r s t contribution. Med.Fac.
Landbouwwv.Rijksuniv.Gent 40: 531-537.
Garibaldi, A., and Pergola, G., 1975.
F u s a r i u m
w i l t resistance in carnation varieties and
Di a n t h u s
species. Med.
Fac.Landbouwwv.Rijksuniv.Gent 40: 545-554.
Tramier, R., and Bettacchini, A., 1974. Mise en évidence d'une souche
de
F u s a r i u m
o x y s p o r u m
f . sp.
d i a n t h i
résistant aux fongicides systémiques. Ann.Phytopathol. 6: 231-236.
Zanardi, D., Loi, T . , and Deligia, S., 1971. Un biennio di l o t t a contro
la fusariosi del garofano in serra. Giornate f i t o p a t o l . : 303-309.
99
Table 1 - C l a s s i f i c a t i o n of the isolates of Fusarium oxysporum f . sp. dianthi tested during t h i s study.
Isolate
1
75
106
102
112
111
103
114
115
116
117
119
120
121
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
l o c a l i t y of i s o l a t i o n
1968
1972
1974
S. Remo
Albenga
S. Remo
II
II
II
II
ii
•I
ii
1975
1976
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
II
Italy
II
II
II
II
II
II
II
Riva Ligure
Imperia
il
Ventimiglia
I
I
Cipressa
II
Albenga
II
Dolceacqua
II
Coldirodi
II
S. Remo
Cabrils
Spain
Antibes
France
Italy
Bussana
H
S. Remo
H
Ventimiglia
ii
M
H
Latina
n
H
Host v a r i e t y
"Astor"
"William Sirrt'
"Sam's Pride?'
"Sara"
"Sam's Pride?'
"Torino"
"Torino"
"Hobby"
"Fulvio"
"Oscar"
"Red Dimond"
"Scania"
"Sam's Pride"
"Astor"
?
?
"Red Sim"
"Oreste"
"Arthur"
"Nora"
"Lorena"
"C.C.Red"
•I
H
H
S. Remo
H
"Tony"
"Nora"
M
H
Imperia
»
Riva Ligure
Ventimiglia
ii
ii
Imperia
H
H
H
H
u
?
7
"Scania"
"Arthur"
"Le rêve"
"Ingrid"
Race
1
2
1
2
1
1
1
1
2
2
2
2
1
1
1
1
2
2
2
2
2
2
1
1
2
2
1
2
2
2
2
Table 2 - Reaction of d i f f e r e n t carnation varieties to the two races
of Fusarium oxysporum f . sp. d i a n t h i .
Variety
Reaction to race
1
2
"American"
Scania 3 C
Red Diamond
White Sim
Arthur
Le rêve
Nora
C.C.Red
C.C.White
R
R
R
R
R
R
R
R
S
S
S
S
S
S
S
s
"Mediterranean"
Orizzonte
Chanel
Mose
Parsifal
Oscar
Davide
Simona
Liguria
Marte
Fulvio
Ciuffetto
G i a l l o Nova
Grazia
Manon
Susanna
Manuela
Nicola
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
Variety
Helen
Matuzia
Katia
Giallo Gambino
Cristina
Hobby
Torino
As tor
Reaction to race
1
2
R
S
S
S
S
S
s
s
S
S
S
s
s
s
s
s
"Miniatures"
Sunshine
Lisa
Peachy
Red Baron
Orange " I f
Ginger Snap
White Royal ette
Purple
"
Cerise
Gus
Vuppi Du
Country
Sam's Pride
Barbi
Pink Barbi
Ingrid
Pauline
Bonanza
Tony
R
R
R
R
R
R
S
S
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
101