Use of Induced Mutants in Seed-propagated Species 



HORST GAUL 1 



Max-Planck-Institut fur Ziichtungsforschung 

 Koln-V ogelsahg, Germafiy 



Plant breeding is controlled evolution. Two of the major factors 

 of evolution, recombination and selection, are extensively used 

 by breeders and refined methods were developed during the first 

 half of this century to exploit them. In the last 30 years research 

 has shown that mutations, the third major factor in evolution, 

 offer an additional tool, which is potentially able to modify and 

 improve cultivated plants in a way similar to the conventional 

 breeding methods. These results, however, do not imply that the 

 efficiency of the new method is equal to or greater than that of 

 the older. If the efficiency can be increased, the mutation technique 

 could be used more often in conjunction with the other breed- 

 ing methods. These questions will be discussed throughout this 

 paper, particularly in the last part. 



The interest in the induction of mutations for plant breeding 

 has increased considerably all over the world in the last 10 years. 

 However, the enhanced interest is not only a consequence of pure 

 objectivity, but also results from the fact that funds for mutation 

 research are often easily obtained. Although theoretical work on 

 the action of mutagenic agents, on the nature of mutations, etc., 

 has a long history, strict and intensive investigations concerning the 

 practical application in breeding has not been conducted until 

 recently. This should be kept in mind when considering the objec- 

 tion often made to the new method, viz., that up to date so few 

 varieties which have their origin in induced mutants have been 

 released. 



In the last few years a series of meetings and symposia has 

 taken place dealing with general radiobiology and with physi- 

 cally and chemically induced mutations from both a theoretical 

 and practical point of view. Among the reviews of the last 5 to 

 6 years relevant to the present paper, the following may be men- 



x The author is grateful to Doctors R. S. Caldecott and R. A. Nilan for critical reading 

 of the manuscript and for linguistic corrections. 



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