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SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
P50 - Effect of timing of inoculation and Fusarium
species on the development of Fusarium head blight
and deoxynivalenol contamination in oat
A. Xue 1 , Y. Chen 1 , C. Ren 2 , and M. Savard 1
1 Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling
Avenue, Ottawa, ON K1A 0C6, Canada; 2 Baicheng Academy of Agricultural Sciences, 17 Sanhe
Road, Baicheng, Jilin 137000, China
E-mail: allen.xue@agr.gc.ca
Fusarium head blight (FHB) is a destructive disease of oats in Canada. To
supplement the development of FHB-resistant cultivars, we examined the
influence of timing of inoculation and pathogenicity of four common Fusarium spp.
on development of FHB and deoxynivalenol (DON) content using 12 oat
genotypes under controlled environment conditions. Both timing of inoculation and
Fusarium spp. significantly affected the development of FHB symptoms and DON
contents in the harvested grain. Early inoculations at or before the complete
emergence of ears resulted in little or no visible FHB symptoms but DON
contaminations ranging from 0.9-3.7 ppm were detected in the harvested grains
from these symptomless plants. Severe levels of FHB were observed on all the
oat genotypes with infected spikelets (IS) ranging from 40 to 75% and DON
content ranging from 6.3 to 10.2 ppm, when inoculated at or after the 50%
anthesis stage. The timing of inoculation at the 50% anthesis was considered the
most appropriate as it allowed a sufficient time for disease development and
assessment prior to the physiological maturity of the plants. Of the four Fusarium
spp., F. culmorum and F. graminearum were equally highly pathogenic, having
areas under the disease progress curve (AUDPC) of 45.3 and 47.3, and DON of
10.4 and 14.3 ppm, respectively. DON was not detected in the harvested grain
from plants inoculated with F. avenaceum or F. sporotrichioides. Fusarium
sporotrichioides resulted in the lowest AUDPC (31.2) and were significantly less
pathogenic than the two highly pathogenic species. Fusarium avenaceum
resulted in AUDPC of 36.7, which was not significantly different from those of
neither the highly pathogenic species nor the weakly pathogenic species. The
Fusarium spp. ´ oat genotype interactions were not signficant, suggesting that
breeding for resistance to F. graminearum may also give enhanced resistance to
other Fusarium spp.
Keywords: Fusarium head blight, oat, Avena sativa, deoxynivalenol
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