Shoot development from hypocotyl protoplasts of sunflower (helianthus annuus l.)

The plant regeneration from sunflower protoplast was achieved by protocols that considerably differ with respect to basal medium and concentration of growth regulators added. In most cases regeneration was restricted to a small proportion of genotypes. In this experiment, sunflower inbred line Ha-74A, with a high regeneration ability was used for protoplast isolation from etiolated hypocotyls. Isolated protoplasts were embedded in agarose droplets and cultured according to different regeneration protocols. The best results were obtained when protoplasts were cultured on L4 medium followed by transfer of regenerated microcalluses to solid regeneration media. Shoot regeneration was achieved by culture of calluses on SE regeneration medium after the treatment with 2.2 mu M thidiazuron