482 MUTATION AND PLANT BREEDING 



of changes wanted by the breeder. Likewise it is not known whether 

 there is a saturation effect of mutagenic treatment which, though 

 permitting the initial successes reported in the literature, might 

 prevent repeated success with repeated application of mutagens to 

 chromosomes at short time intervals in recurrent selection cycles. 

 Also still to be learned are the relative efficacies of mutagenic treat- 

 ments and hybridization when applied in conjunction in species 

 other than peanuts. 



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