PROBLEMS OF CARYOPSIS AND STABILITY OF WINTER AND SPRING FORMS OF CEREALS TO PHYTOPATHOGENIC FUNGI OF GENUS FUSARIUM LINK - Ecological Consequences of Increasing Crop Productivity - page 99

11.2.1 SELECTION OF FUNGI IN A PURE CULTURE
Seeds were washed in 0.1 percent solution of streptomycin. After a torrefaction, they
were placed in a moist chamber at the temperature of 24-26 ° С. In 2-3 days, seeds with
germinating mycelium were put on agar in double-dish (in sterile terms) and kept in
thermostat at the temperature of 24-26 ° С. Pure culture was saved on a slanting agar.
Taking into account the fact that pathogens of the genus Fusarium are rather com-
mon in the cereals (both spring and winter forms) in Tyumen region and can cause
signifi cant yield losses, we conducted laboratory and fi eld studies on the biology of
this genus. The experiments included method of phytopathological analysis of seeds
with the calculation of the disease index [5-9].

11.3 RESULTS AND DISCUSSION
The incidence of seeds by the pathogenic fungi depends in a great extent on the weath-
er conditions during the ripening and harvesting of grain. Therefore, the formation
of the microflora of winter rye grains was studied in the years 2002 (11 samples),
characterized by high humidity, and 2003 (17 samples), favorable for ripening grain.
Regardless of the growing conditions, the fungal spores of the genus Alternaria
dominated in most of grains. Fungi of the genus Trichothecium in 2002 were found in
17 percent of seeds, and in 2003 in 1.5 percent of seeds (Figure 11.1).

FIGURE 11.1 The microflora of winter rye grains from different years of harvest: (A) 2002

and (B) 2003.

Among the most harmful pathogens, causing root rot and spot, pathogens from the
genera Helminthosporium and Fusarium were detected. The number of grains affected
by Fusarium was 3.6 percent in 2002 and 0.6 percent in 2003; blight affected 0.7 and
7.7 percent of grains, respectively.