SEGREGATION OF BIOCHEMICAL-GENETIC DETERMINANTS IN SOMACLONAL VARIANTS OF THE POTATO INTERSPECIFIC SOMATIC HYBRID

The segregation of parental genetic determinants in the potato somatic hybrid (Solanum tuberosum L. x S. chacoense Bitt.) was investigated while obtaining somaclonal plant variants from callus. By their morphological traits, some somaclones resembled the cultivated parental genotype (S. tuberosum, cv. Priekul'-skii rannii). As we did not obtain seeds from somaclone lines and, therefore, could not perform hybrid analysis, we attempted to identify genetic determinants of somaclone lines by comparing their patterns of reserve proteins, isoesterases, and isoperoxidases in the microtubers and isoenzyme patterns in the roots, stems, and leaves separated from the test-tube plants, using isoelectrofocusing and electrophoresis according to Davis. The genome of the somatic hybrid retained the components of both parental forms, although the components characteristic of the wild species (S. chacoense) dominated the protein pattern. The expression of the individual protein components characteristic of two parents varied in somaclone lines, indicating the segregation of the hybrid genome. In addition, several protein components, absent from the parental forms and their hybrid, were observed in some somaclone lines. Due to new traits and new combinations of traits, the somaclone variants of somatic hybrids apparently present a prospective source for potato breeding.