Dobroudja Agricultural Institute, BG-9520 General Toshevo, Bulgaria
ENCHEVA, J., 2004. Indirect organogenesis and somatic embryogenesis of sunflower (Helianthus annuus L.) immature embryos and its application for crop improvement. Bulg. J. Agric. Sci., 10: 549-556
Immature zygotic embryos from ten fertility restorer lines were used as donor material for induction of indirect organogenesis and somatic embryogenesis in sunflower (Helianthus annuus L.). In our experiment we observed a process of formation of a large number of non-differentiated embryo-like structures without apical and root meristems (outgrowth) which did not germinate into whole plants, of monopolar structures, i.e. indirect organogenesis and single cases of bipolar structures (indirect somatic embryogenesis). Genotypes R147, L-2128 and RHA-857 possessed the highest morphogenetic response, 11.5 %, 10.0 %, and 8.9 %, respectively. Among the R0 plants, a considerable phenotype variation was observed. Plants with stable morphologic and biochemical, besides epigenic, changes were registered among the regenerants obtained. After continuous selfing and individual breeding the somaclonal lines R 1373, R 1378, R 1380 and R 1383 (R10) of genotype 147 R were selected due to significant statistical, morphological and biochemical changes and their good combining ability. The genetic modifications observed in the regenerants included agronomic traits such as oil content in seed, 1000 seed weight, plant height, number of leaves, leaf width, leaf length, petiole length, internode length, head diameter, stem diameter, number of branches and length of branches. Line R 1378 showed higher oil content in seed in comparison to the standard R 147. All lines investigated were characterized with modified architecture. Lines R 1378 and R 1383 were with higher stem, with less leaf, with smaller lives size, head and stem diameter.
Somaclonal variation through indirect organogenesis and somatic embryogenesis has facilitated the development of genetically heritable variation in sunflower, which can be used with success at sunflower breeding programme.