Resume of the Symposium 



S. G. STEPHENS 



North Carolina State College, 

 Raleigh, N. C. 



A resume of our proceedings during the past week should prop- 

 erly require a summing-up in organized fashion of all the 

 papers and discussions which have been presented here. But no more 

 than a cursory study of our program is necessary to appreciate that 

 this "Symposium on Mutation and Plant Breeding" includes two 

 rather distinct areas of interest. One is concerned with the nature 

 of genetic material, the other with the use of mutation in plant 

 breeding. One attempts to interpret mutant events in terms of recent 

 advances in genetic theory, the other endeavors to improve methods 

 of producing and using mutants. The goals are different and so 

 are the experimental procedures. They have in common certain 

 "tools of trade" (mutagenic agents) and an interest in refining them 

 for more precise usage. The search for specific mutagens as a source 

 of directed mutations occupies the attention of workers in both 

 areas, though it is by no means clear to this reviewer that the "spec- 

 ificity" they seek is of the same nature or order. 



To review adequately two diverse and rapidly growing areas of 

 research requires a level of competence, and first hand experience 

 in both, which I do not possess. The embarrassing fact is that I have 

 never intentionally used a mutagen, induced a mutant, nor applied 

 the same to the betterment of the plant kingdom. Free of first hand 

 experience and the pre-conditioning necessarily associated with it, 

 I can only hope to be objective at the risk of being naive. If I am 

 not mistaken, this is a situation which I share with a number of 

 geneticists and plant breeders, and it is for them that this review is 

 primarily intended. 



Mutation and the Nature of Genetic Material 



Early in this symposium, Auerbach pointed out that studies 

 on the nature and action of mutagens have not led to new infor- 

 mation on the nature of the gene. On the contrary, concepts of the 

 nature of the gene, derived from DNA structure, have led to new 



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