SUGAR BEET ROOT ROTS DURING VEGETATION PERIOD IN UKRAINE - Ecological Consequences of Increasing Crop Productivity - page 212

Mycological tests of soils have showed that among the fungi Penіcіllіum species a
great share of selected varieties made up toxin producing ones: Penіcіllіum cyaco-ful-
vum, P. rubrum, P. purpurogennum . At the same time, the number of toxic species such
as Aspergіllus, Cladospopium, Stemphilium, Alternaria, and Mucorales has increased .
Besides, the number of fungi-antagonists Trichoderma and Botrytis is decreased .
The plants resistance to diseases on contaminated soils decreases. It is especially
true if hybrids option for sowing is improper to a zone and followed by unfavorable
weather conditions. Thus, early affection of roots with causative agents of deceases is
common.
Popkova determined a correlation between potato periderm thicknesses and its
resistance to affection.
As early as 1990s, Japanese scientists noted that sugar beet cell walls, having rap-
idly increasing weight, were less thick and receptive to destruction with fungi [28].
The diverse origin hybrid cells examination has shown the differences in the size
of cell walls and intercellulars. One can see the differences in the cell density in the
fi rst 10 layers (Figures 20.11 and 20.12).
FIGURE 20.11 Size of cell walls and intercellulars of sugar beet hybrids of different origin:
(A)—home hybrid; (В)—foreign hybrid.