Establishing the regeneration system of sunflower
向日葵离体再生体系的建立

In order to establish a high efficient regeneration system of sunflower, we optimized the process of callus induction, differentiation and rooting by screening the optimum genotype, explant materials, hormone and cytokine concentration and additives. The results indicated that hybrid sunflowers were easier to regenerate than selfing ones; The best explant was four days cotyledon. The optimum induction medium was Murashige and Skoog (MS) +2.0 mg/L 6-benzyladenine (6-BA)+0.5 mg/L naphthaleneacetic acid (NAA)+1.0 mg/L kinetin (KT). The maximum rate of callus induction was 100%. The optimum differentiation medium was MS +0.2 mg/L 6-BA +0.5 mg/L NAA +0.3 mg/L KT +0.3 mg/L silver nitrate (AgNO3)+0.2 g/L active carbon (AC), and the buds differentiation rate was up to 71%. The best rooting culture medium was 1/2 MS +0.6 mg/L indolebutyric acid (IBA). The highest rooting rate was 77%. The analysis of variance showed that genotype, explants growth time, different kinds and concentration of hormone, AC concentration had a significant effect on sunflower regeneration.