| Tuber
Internal Growth Defects: BLACKHEART
Blackheart
can develop around harvest, in storage and in transit as inside
trucks. It is caused by an oxygen deficit at the center of the tuber.
Oxygen deprivation results in asphyxiation, loss of respiration,
and death of cells.
External
Appearance:
It
can not be detected externally.
Diagnostic
Method:
Cut
longitudinally.
Internal
Appearance:
Blackheart
appears as an internal browning to blacking of center tissue. Usually,
there is no cavity. Pattern is irregular but margins are well defined.
Affected tissue is firm, not soft as with leak, but, when temperature
is greater than 65oF, it may turn soft and inky. There is no odor
as with leak.
Development:
Any
pre-harvest, storage and transit condition that prevents oxygen
from reaching the tuber center will result in blackheart. These
conditions are commonly poor ventilation, water-logging, long exposure
to high field temperatures (>90oF) before harvest, and prolonged
storage at low temperatures (<35oF). Tubers used as seed can
have lower vigor and stand since tuber starch reduced in bulk and
may not support emergence.
Cooking
Appearance:
Boiled
or baked tubers will be black in the center. Chips usually have
a black center or a hole. Fries will be black in the middle or be
split in two.
Control
Measures:
- Good
ventilation in storage prevents blackheart.
- Avoid
poorly drained ground. Avoid flooded areas.
- Avoid
closed bins, deep piles and poor ventilation.
- Avoid
poorly aerated trucks and storage.
- Avoid
temperature extremes, inhibit diffusion of oxygen through tuber.
Summary:
Internal Disorders |
