**Session V -- Effective Pest (Pathogen, Insect, Weeds) Management --
Poster V-2\***

**Susceptibility of Oat Germplasm to *Fusarium* Infection and Mycotoxin
Accumulation in Grains**

Gavrilova O.^1^, Gagkaeva T.^1^, Burkin A.^2^, Kononenko G.^2^, Loskutov
I. ^3^

*- ^1^*All-Russian Institute of Plant Protection (VIZR),
St.-Petersburg - Pushkin, Russian Federation*.*

*- ^2^*All-Russian Institute for Veterinary Sanitation, Hygiene and
Ecology, Moscow, Russian Federation

*- ^3^*N.I.Vavilov All-Russian Research Institute of Plant Industry,
St.-Peterburg, Russian Federation*.*

*Fusarium* head blight (FHB) is the most damaging disease of small grain
cereals, but researches placed low emphasis on *Fusarium* infection in
oat. At present, the increase of mycotoxins in harvest of oats was noted
(Kononenko, Burkin, 2002, Pettersson, 2007). The resistance of oats to
FHB is poorly known in compare with other grain cereals, because the
interest in search of sources of resistance to this disease quickened
significantly (Tekauz, 2003, 2005).

The goal of our research was to identify the resistant oats germplasm to
FHB and accumulation of mycotoxins. The oats germplasm (A. sativa and A.
byzantina) were received from the collection of VIR and represented more
100 both hulled and hulless oats from different regions of Russia and
the whole world (China, Mongolia, Japan, USA, Canada, Denmark, UK,
Australia et al.). The VIR (Vavilov\' Institute of Plant Industry) is
one of the largest *Avena* genebank in the world (13000 samples of 26
species) and possesses unique germplasm (Loskutov, 2007).

In the nursery located in Leningrad region each sample was planted in 1
m^2^ plots with 15 cm x 3 cm spacing between plants in two repetitions.
Before heading of oats, the inoculum (mixture of four *F.
sporotrichioides* strains on autoclaveted grain) was scattered on the
soil surface at the rate of 150 g per sq.m. *F. culmorum, F. poae* and
*F. avenaceum* fungi are typical pathogens of cereals in this area and
during the vegetation these pathogen may infect plants, too (Shipilova,
Gagkaeva, 1992). Height of plants was measured as the distance from the
base of the plant to the top of ear. Oats were recorded in groups as
early- and later-maturing plants.

After hand thrashing, 100 grains from every sample were surface
sterilized by 70% ethanol and put into high-humid plastic boxes. The
grain infection of hulled samples was estimated by two different ways:
as natural covered by hull and as hulless after mechanically shelling.
One week later the number of grains sheeted by mycelium of fungi and
total percentage of *Fusarium* damaged grain (FDG) were estimated. For
toxins determination every hull-less and hulled grain samples were
ground with laboratory mill. Mycotoxin contents were determined by ELISA
with detection limits: T-2 and HT-2 toxins (4
![](media/image1.png){width="8.333333333333333e-2in"
height="0.12430555555555556in"}g kg^-1^), DON (40
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^), DAS (50
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^), ZEN (20
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^) (Kononenko, Burkin, 2002).

From inoculation to harvest, a little evidence of FHB could be seen on
the plants. Although visual FHB symptoms were not noted, the significant
variation 0-100% in grain infection were found between oats germplasm.
All hulless oats (8 landraces and 6 cultivars) showed low mean
percentage of FDG --1.9% (maximum 6%). In total, hulled oats (29
landraces and 62 cultivars) were significantly more susceptible in
contrary with hulless oats. There was a significant difference between
*Fusarium* severity in the naturally covered and the hulless after
shelling grain samples -- 17.3 % and 9.6 %, respectively. Obviously,
hull plays an important role in the protection grain against penetration
*Fusarium* infection.

The low occurrence of *Fusarium* in hulless oats was resulting in the
mycotoxin contamination - Т-2 toxin 0-774
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^ and DON -- 57-1256
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^. It was shown the period of
maturing plants has associated with toxin content. The later- maturing
oats accumulate the mycotoxins abundantly (mean Т-2 toxin -- 268
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^, DON -- 297
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^) in compare with early-maturing
oats (mean Т-2 toxin -- 78
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^, DON -- 378
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^). Hulled oats germplasm showed a
broad range in the toxins accumulation. In early - maturing plants Т-2
toxin contents ranged from 0-3540
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^ and DON -- 53-1990
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^ and in later- maturing plants
Т-2 toxin 0- 5620 ![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^ and DON 100-11190
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^.

In half of all analyzed oats samples DAS was detected (the maximum of
this toxin 305 ![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^). ZEA was detected only in five
samples, when the maximum of toxin (2840
![](media/image1.png){width="8.333333333333333e-2in"
height="0.11458333333333333in"}g kg^-1^) in oat line from USA VIR-13093
(C.I.8447) was found.

The plant height of hull-less oats varied in the limits 86.4-117.6 cm
and hulled germplasm 41.2- 140.9 cm. It was speculated that grain
infection was related to plant height, where taller oat samples have
ears held at greater distances from sources of the inoculum on soil
surface. However, we have not found a significant correlation between
plant height and grain infection. Our results indicated the significant
differences in disease severity between oats germplasm of a similar
height. For example, the hulled oat line (Av21/1 from Japan, VIR-14855)
with the shortest straw (45.5 cm) has shown the high resistance - 2% FDG
and cultivar Dalyup from Australia (VIR-14175) with the same height was
susceptible - 46% FDG. It was not detected the correlation between grain
infection and mycotoxin accumulation. The results generally support
several aspects of resistance in oats, which are controlled by different
genetic systems, as well as the resistance in wheat (Mesterhazy, 2002).
One of the less damaged hulless oats with the low levels of toxins was
cv. Numbat from Australia (VIR-14851). The four hulled germplasm of oats
VIR-6963 (Japan), VIR-8688 (Buryatia, Russia), VIR-14231 (Moscow region,
Russia) and VIR-14419 (Ulianovsk region, Russia) seems to be suitable
genetic resources for resistance to fungal invasion and accumulation of
mycotoxins. Studies of the resistance and the accumulation of *Fusarium*
mycotoxins in oats are in progress.