Subject: strange potato physiological disorder

From: Yves Leclerc <[email-masked]>
Date: 30 May 1995 13:49:12 GMT

we are seeking assistance in the identification of 
a strange potato disorder (physiological ?).  we have 
recently encoutered a strange disorder 
in a potato seed lot of "Superior" stored since fall of 1994.
the disorder was located mostly in the medullar area of tubers 
but sometime extended to the cortex area, but never reached. 
the disorder consisted of several black streaks within the 
medullar area. the streaks were somewhat concentric appearing as 
parallel arcs.  they were limited to some areas of the tuber.  
small cavities were often developed within the black streaks.  
when looking from a distance (50 cm), the streaks were noticibly 
located in a darker (greyish) area of the tuber.  
Tubers showing typical black heart symptoms were also found in 
the seed lot.  tubers did not decay after cutting. the disorder 
was present in approximately 50% of the tubers.  
the growing season was dryer than ususal and a fair proportion 
of tubers also showed brown centre and hollow heart.  we would 
appreciate any information on this strange disorder.