Production of stable transgenic sunflowers (Helianthus annuus L.) from wounded immature embryos by particle bombardment and co-cultivation with Agrobacterium tumefaciens

Split embryonic axes of 21-day old immature sunflower (Helianthus annuus L.) embryos were bombarded by microparticles and then co-cultured with disarmed Agrobacterium tumefaciens strain EHA105 bearing a binary vector carrying nptII and uidA genes. Apical shoot bud development and organogenesis induced on the explants led T₀ transgenic plants. Southern blot analysis revealed complex integration patterns in T₀ plants. The uidA gene segregated as a dominant trait and single-insertion events were observed in T₁ plants. Patterns similar to those of T₁ plants were observed in T₂ progeny.