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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
P63 - Interspecific and intraspecific variability of
Fusarium fungi
T. Kolomiets, L. Pankratova, E. Kovalenko
All-Russian Research Institute of Phytopathology; Moscow region, Odintsovo district, str. Institute, b.5,
VNIIF; Moscow Russia
E-mail: lomi1@yandex.ru
Pathogen fungi of genus Fusarium causing fusarium head blight, root rot and
snow mold of wheat have the high genetic variability. Samples from infected
plants consist of several species and special forms which are different by
morphology and cultural traits, sporulation ability, pathogenicity and phytotoxicity.
There were 2-7 morphotypes of each Fusarium species identified by the long-time
observation of morphology and cultural traits. The correlation between
sporulation ability and morphology of Fusarium isolates was not shown. The
reliable differences were shown for pathogenicity and phytotoxicity between
Fusarium spp. F. sporotrichioides and F. sambucinum(Gibberella pulicaris) have
the high level of pathogenicity. The maximum of phytotoxicity was demonstrated
for F. graminearum (G.zea) and F.nivalis (Monographella nivalis). The moderate
level of pathogenicity and phytotoxicity was demonstrated for F. oxysporum and
F. culmorum. Pathogenic and toxic fungi were presented during the whole of
vegetation of wheat cultivars. Fusarium fungi have the high intraspecific
variability. A sample from 19 isolates of F. graminearum was composed from 10
isolates with high phytotoxicity, from 8 without any phytotoxicity, and a single with
moderate phytotoxicity. A sample from 13 isolates of F. oxysporum consisted of a
single isolate with moderate phytotoxicity, 6 isolates with low phytotoxicity and 6
isolates without any phytotoxicity. Isolates with high toxicity have not always high
pathogenicity. There were 3 isolates of F. graminearum without any pathogenicity
and 6 with moderate pathogenicity from the total sample of high toxigenic
isolates. Two directly contrary isolates of F. сulmorum were selected by
pathogenicity and phytotoxicity. They are pathogenic but they have low
phytotoxicity up to nothing. No isolates with complex of high pathogenicity and
phytotoxicity were identified through Fusarium fungi from wheat.
Keywords: Fusarium, variability, pathogenicity, phytotoxicity
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