BUD-MUTATION IN THE POTATO AND ITS AGRICULTURAL 
SIGNIFICANCE 
Although the view that the plants of a certain variety of potato 
would gradually alter is a very old and widespread one, it has 
never satisfactorily been demonstrated. The deterioration in cultiva- 
tion value is at present attributed to the tremendous increase of the so 
called degeneration diseases. PETHYBRIDGE (48) and OORTWIJN BOT- 
JES (45) state that some varieties are now evidently more affected by 
certain diseases than some decades ago. Such observations are not con- 
clusive however and OoRTWIJN BOTJES has rightly pointed out that 
the cause of the disease may have become changed. 
On the other hand, vegetatively produced sudden alterations 
have often been observed among plants. A great number of such cases 
are enumerated by CARRIÈRE (12, 1865), DARWIN (18, 1868) and CRA- 
MER (15 and 16, 1905 and 1907). 
The potato is not an easy subject for investigations of this kind. 
Mixing with other varieties, modifications and diseases have often, 
wrongly, ed to the conclusion that bud-mutation was the cause of the 
observed differences with the original stock. All cases in which rigid 
attention has not been given to such possible causes of error, should 
be considered with the necessary scepsis. 
In the literature treating of the potato, references to bud-mutation 
are not rare. About 80 cases could be collected, many, however, are 
far from conclusive. The question whether bud-mutation really occurs 
in the case of the potato has often been discussed. While some support 
the view of its occurrence others are violently opposed to it, while 
still others hold the view that bud-mutation does occur but affects 
colour only. The papers and discussions at the International Potato 
Conference, London 1921, show, that the occurrence of bud-mutation 
among potatoes is now pretty generally accepted as a fact. The amount 
of reliable data, remains small, however. One seems to be incli- 
ned to the view that besides measures to counteract the damage cau- 
sed by diseases and besides the growing of new variaties from seed, 
bud-mutation will in future play a role in the prevention of deteriora- 
tion and in the general improvement of the potato. 
During the past seven years, I have as completely as possible collec- 
ted and examined all cases which have been considered as budmuta- 
