SOMACLONAL VARIATION INDUCED BY FUSARIC ACID

Resistance to toxin and other types of somaclonal variation of regenerated tomato plants obtained, as a result of toxin selection in vitro, was analysed. Toxin is shown to bc not only a selecting agent but also a mutagen and recombinogen (in the latter case, the hybrid F1 ftssue was used). Genetical peculiarities of the original forms and their resistance to the pathogen has substantial influence on the spectrum of somaclonal variation. It was proved experimentally that adaptation of plant genome to toxin pathogen in vitro occurs at the expense of polyploidization and reversion to the wild type. On the basis of the results obtained, two types of resistance induced by the toxin were established. The first type belongs to the cases of resistance being acquired without any change in the main characteristics of the original form. The second type obtained was characterized by profound changes (polyploid, reversion to the wild type, tc.), when the original phenotype is not maintained.