Increasing the Efficiency of Mutation Induction 1 



R. A. NILAN and C. F. KONZAK 



Washington State University, Pullman, Washington 



Great strides have been made in the study and use of induced 

 mutations for the improvement of agricultural crops. This 

 success has spurred researchers to accelerate their pace toward obtain- 

 ing greater efficiency of mutation induction for plant improvement 

 programs of the future. 



A principal approach to this endeavor is through investigations 

 of the induced mutation process. The specific objectives of these 

 investigations are (a) to increase the total induced mutation yield 

 through increasing dose tolerance of tissues and through altering the 

 ratios of mutations to chromosome aberrations, and (b) to control and 

 direct the induced mutation process for the production of desired 

 mutations. 



These objectives are being pursued through the control and 

 manipulation of secondary factors which alter the response of tissues 

 to radiation through the use of certain chemical mutagens that 

 induce effects different from radiation and through the transfer of 



plant-cell compounds from radio-resistant to radio-sensitive species. 

 Several other approaches to increasing mutation yield and to 

 increasing the economic feasibility of artificial mutagenesis in future 

 plant breeding programs have been investigated. These include (a) 

 the use of pollen and embryos in mutation induction, (b) diploidiza- 

 tion of loci in polyploids by mutagen treatment, (c) alteration of 

 reproductive mechanisms (especially self-incompatibility and apom- 

 ixis) by mutagen treatment, and (d) development of efficient recur- 

 rent irradiation techniques. Such approaches are concerned with the 

 appearance, detection, and selection of induced mutations rather than 

 with the induced mutation process per se. However, they are so 

 intimately related to the problem of increasing the efficiency of muta- 

 tion induction that they must be considered in this discussion. 



^Scientific Paper No. 2065 Washington Agricultural Experiment Stations, Pullman, 

 Wash. Research supported by U. S. Atomic Energy Commission Contract AT(45-l)-353 

 and U. S. Public Health Service Grant A-2184. 



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