Radiation effects on the one locus-gametophytic system of self-incompatibility in higher plants : A review

A brief review is presented of the temporary and permanent effects which are usually observed after irradiation treatment of self-incompatible plants with a one locus-system of gametophytic incompatibility and attempts are made to demonstrate that the study and exploitation of such effects can lead to important advances in the fields of mutation breeding, radiobiology per se and biochemistry.The fact that irradiation treatment has only negative effects on the self-incompatibility system (inactivation of the incompatibility reaction and/or genetic losses at the S locus) is discussed in relation to the positive changes (formation of new specificities) which are observed during inbreeding. In this connection, the suggestion is made that the self-incompatible plant may perhaps be equipped with a switch system or a mutagenic mechanism which enables it to display a new specificity when this new specificity is needed for increasing the level of genetic polymorphism in the population to which the plant belongs.