Agriculture Reference
In-Depth Information
Visual examination of fungal structures accompanying the seed lot or loosely attached to the seed coat.
This method is designed to detect structures not visible to the naked eye, but are either mixed with seed in
the seed lots or are loosely attached to the seed coat. Seeds are washed with water, usually with a detergent
to release spores from seed coats. The washings are then centrifuged, the pellet removed, and examined
under a microscope for fungal structures such as spores. The two smut pathogens of corn,
Ustilago zeae,
the
cause of common smut, and
Spacelotheca rediana,
the cause of head smut, can be detected by this method
(Fig. 10.5).
Figure 10.4. An infection of barley by
Ustilago nuda
, the cause of loose smut of barley, in (left) leaves,
and (right) a microscopic view of the embryo infection (left photo by Gabriel Bratu, right photo by Hanna
Friberg, Swedish University of Agricultural Sciences.)
Figure 10.5. Smut infections of corn:
Ustilago zeae
, the cause of common smut, and
Sphacelotheca reiliana
,
the cause of head smut (courtesy of Landesbildungsserver Baden-Württemberg).
