Immature zygotic embryos from nine inbred lines of sunflower (Helian-thus annuus L.) were used as a donor material for the induction of direct organogenesis and somatic embryogenesis. A portion of the embryos was treated with Cs 137 gamma radiation before plating, at doses of 5. 10 and 15 Gy.

Three induction media were used in the experiments - AO by Freyssinet and Freyssinet (1988). El (modified AO medium) and TPM by Wilcox et al.

The regeneration was strongly increased with the dose of 5 Gy in line Z-8-A in the medium AO. followed by the dose of 10 Gy in the lines 1395 Rf in AO and RNA-801 in El. For the three media and all genotypes the dose of 5 Gy in the medium AO appear to be most appropriate for increasing the frequency of plant regeneration.