As a result of hybridization between the Bulgarian fertility restorer line R 2574 and mixed pollen from a polycross population of known genetic composition, and treatment of immature embryos with gamma radiation or ultrasound, a large number of new fertility restorer lines were developed. Lines R 114, R 115, and R 116, subjected to investigation in this study, are characterized with significant changes concerning most of the studied characters. The increased number of seeds per head in lines R 115 and R 116, the increased 1000 seed weight in line R 114, the 100% resistance to the parasite Orobanche in lines R 114 and R 116, and the very good combining ability in hybridization are the desired combination in the breeding program of sunflower. The hybrids Rada and 80, developed with the participation of lines R 114 and R 116, considerably exceeded the mean standard (the Bulgarian commercial hybrids Albena and Super Start) in seed and oil yields, simultaneously possessing high resistance to the Orobanche population of races distributed in Bulgaria. In 2002, the hybrid Rada was registered for testing by State Variety Testing Commission and it exceeded the mean standard of the country. The combined use of interlinear hybridization with physical mutagenesis or ultrasound and the embryo culture method leads to increased genetic variability in sunflower and to a considerable shortening of the breeding process, producing 5 generations within a single year.

The pesticide formulation prepared as "ready to be used plant protection product" on the basis of tobacco oil was created and tested in two years field trials against powdery mildew of wheat (Blumeria graminis f. sp. tritici). The results showed strong fungicidal effect without any phytotoxic activities (chemotherapeutic coefficient = 10) onto treated plants. This indicates the future development of this pesticide formulation as effective, natural friendly and cheap product for plant protection, which can be used both in commercial and organic agriculture.