Adventitious bud regeneration from cotyledonary node, hypocotyl, cotyledon and euphylla of various genotypes of sunflower (Helianthus annuus L.)

Isolated culture of sunflower is significantly important in seeking new species of sunflowers with plenty of essential oil by modern biotechnologies. Thus, the callus development and adventitious bud regeneration from various explants of sunflower were studied by in vitro tissue cultures. It was found that the callus were readily formed on six genotype explants cultured in media with IAA and 6-BA, but adventitious bud regeneration from these callus was relatively weak. The adventitious bud regeneration inductivities of four tissue explants from different genotype sunflowers were ordered as followed: cotyledonary nodes > hypocotyls > cotyledons > euphyllas. The desired concentrations of 6-BA inducing adventitious bud regeneration were at 1.2–1.8 mg/l for cotyledonary nodes, 1.8 mg/l for hypocotyls and 0.6 mg/l for cotyledons, respectively. But no adventitious buds were differentiated from euphyllas only by 6-BA. The best medium for organogenesis was composed of MS+0.03 mg/l IAA+1.2–1.5 mg/6-BA by which euphyllas also were induced to regenerate adventitious buds with an averagely 20.83% inductivity. Among several genotype sunflowers, PR29 had the highest regeneration frequency and the regenerated plantlet has been successfully cultured.