INVESTIGADORES
ALVAREZ cora Lilia
artículos
Título:
Aggressiveness of Fusarium graminearum sensu stricto isolates in wheat kernels in Argentina
Autor/es:
CORA LILIA ALVAREZ, STEFANIA SOMMA, ANTONIO MORETTI AND VIRGINIA FERNÁNDEZ PINTO
Revista:
JOURNAL OF PHYTOPATHOLOGY-PHYTOPATHOLOGISCHE ZEITSCHRIFT
Editorial:
Willey-Blackwell
Referencias:
Lugar: Alemania; Año: 2009 p. 1 - 9
ISSN:
0931-1785
Resumen:
This study was designed to investigate the degree of aggressiveness of
Fusarium graminearum sensu stricto isolates and its relationship with
trichothecene production. In order to characterize Fusarium strains
aggressiveness, disease severity was visually assessed as the
percentage of spikelets bleached per ear. The severity ranged from a
minimum of 27.19% seven days after inoculation to a maximum of 84.73%
at the end of the experiment. At maturity the ears wereharvested
and threshed for grain weight determination. All treatments showed
significant differences in kernel weight with respect to the control
plants, with a yield reduction of 3585% in comparison with the yield
of the control. Grains infected by F. graminearum may contain
significant levels of mycotoxins like trichothecenes. No correlation
was found betweenaggressiveness and the toxins in the kernels at
maturity, taking into consideration not only the quantity but also the
type of toxin (nivalenol, deoxynivalenol or their acetylderivatives).
Kernel weight reduction was a better estimator of the presence of
deoxynivalenol in the kernels than the area under the disease progress
curve (AUDPC) calculated with severity ratings.The amplified
fragment length polymorphism (AFLP) technique was used to establish
genetic relationships between 18 Argentinean isolates and eight
referencestrains of the Fusarium graminearum complex. All the
isolates studied grouped with the two F. graminearum s. str. reference
isolates, with a similarity coefficientgreater than 75%. The other
reference strains of the F. graminearum complex were clearly separated,
with similarities ranging between 55 and 73%. The AFLP groups had no
relationship with toxin accumulation on kernels or with the
geographical origin of the isolates. Great heterogeneity was found in
the AUDPC, yield reduction and toxin accumulation values across the
regions.