nybom: vegetativelv propagated species 253 



We all know that the experiences and the opinions based on these 

 studies in many cases turned out to be quite negative. Either one did 

 not find any greater amounts of mutations at all, or those obtained 

 did not appear very promising as a basis for the production of new 

 and better varieties. 



The interest in induced mutations was revived when it indeed 

 turned out to be possible to produce undeniable, progressive muta- 

 tions of practical interest for the breeder (17, 39, 46). The increasing 

 interest in the application of atomic sciences also has helped to focus 

 the interest of the plant breeder on this "new" path or tool in plant 

 breeding, the mutation method (47, 107). 



Although the inclination of many plant breeders has changed 

 "from fairly sceptic to moderately optimistic" (86), one still meets 

 fairly conflicting statements concerning the prospects of the mutation 

 method. It is one of the chief aims of the present conference to collect 

 our experiences, to focus the interest on the most promising areas, 

 and, as far as possible, to present a realistic evaluation of the mutation 

 method in plant breeding. 



A Survey of Mutation Experiments in 

 Vegetativelv Propagated Plants 



In order to give an idea of the achievements arrived at in various 

 plants and to provide a basis for the discussion to follow, I shall begin 

 by summarizing experiences from the more important mutation 

 experiments in the vegetatively propagated plants that have been 

 published. 



Potatoes 



Some of the more extensive and most promising work on induced 

 mutations has been reported with the potato by my compatriot, A. 

 Heiken. As I happen to be rather familiar with his results, I shall 

 take the liberty to deal with them at some length. This may be the 

 more justified as his work is published in a journal that may not be 

 generally available. 



However, for the sake of justice, I should like to begin by refer- 

 ring to the classical work of Asseyeva. She published during the 

 twenties and early thirties a series of papers on the chimaeric structure 

 of different spontaneous potato mutants (2). She found that most of 

 the spontaneous mutants were periclinal chimaeras; and with the 



