DOUBLED HAPLOID PRODUCTION OF SUNFLOWER (HELIANTHUS-ANNUUS L.) THROUGH IRRADIATED POLLEN-INDUCED PARTHENOGENESIS

Induced parthenogenesis as a possible method of haploidization in sunf lower (H. annuus L.) was tested in previous investigations (Todorova e t al., 1994) and conditions for reproducible regeneration of gynogenic doubled haploids were established by the present work. Forty eight tr eatments were studied, involving four pollen donors and four recipient hybrids. Pollen was irradiated with doses of 300 Gy, 600 Gy and 900 G y. In total, 2279 embryos were cultivated in vitro of which 1107 plant s were obtained and 582 of them produced seeds after selfing. The ploi dy level of the regenerants was evaluated at the two-three leaf stage and 296 of the plantlets obtained were haploids. Some of them underwen t spontaneous diploidization, the others were treated with colchicine solution for chromosome doubling. The diploid plantlets were checked f or their gynogenic origin by genetical and biochemical methods. The ef fectiveness of the method expressed as the number of agronomically use ful DH lines to the number obtained that were fertile and resistant to downy mildew, branched and unbranched plants was 8,6% on average.