Steroidal glycoalkaloids in tubers and leaves of Solanum species used in potato breeding

Abstract

The compositions of glycosidic-bound steroidal alkaloids (SA) of Solanum species used in potato breeding were assessed by capillary gas chromatography using simultaneous nitrogen-specific (NPD) and flameionisation detection (FID). High concentrations of solanidine glycosides and other steroidal glycoalkaloids, amongst which the teratogenic SA solasodine, were found in tubers and leaves of wild species. In addition unidentified compounds were found, which were most probably SA as was shown by their NPD/FID response ratios. The total glycoalkaloid contents varied from 123 to 7348 mg/kg fresh weight. Tubers of cultivars, corresponding in small size and grown under the same conditions as tubers of the wild species, showed contents of solanidine glycosides which were 2–3 times higher than those of field-grown normal tubers (126–721 vs 40–360 mg/kg fresh weight, respectively). In some cases the SA compositions of the tubers were markedly different from those of the leaves of the same plant or they varied between accessions of the same species. Also the growing conditions appeared to influence the composition quantitatively and qualitatively.