Effectiveness and efficiency of mutagenic treatments

The proper choices of a mutagenic treatment and of a method for selecting mutants are of primary importance in mutation breeding. The former determines the mutation rate per cell at the time of treatment, and the latter influences the proportion of target mutants in M2 or later generations. This article focuses on the former. The problems of effectiveness and efficiency of mutagenic treatments in mutation breeding of crop plants have long been discussed by several workers (NILAN et al. 1965, KAWAI 1975, 1986), but it still seems that scientific consensus on the problem has not been reached. Here I present my view on the issue, based chiefly on the results obtained with different mutagenic treatments at the Institute of Radiation Breeding. The materials used were seeds of an uzu cultivar, Chikurin Ibaraki 1, of barley, a diploid self-fertilizing species, unless otherwise stated. In studies of the effectiveness and efficiency of mutagenic treatments, the use of one and the same genotype throughout experiments is most important. (author)