An efficient in vitro propagation protocol for direct organogenesis from root explants of a multi-purpose plant, Broussonetia papyrifera (L.) L’Hér. ex Vent

•Efficient regeneration system was constructed by using Broussonetia papyrifera root as explants.•The best effect is to use three kinds of hormone at the same time, they cannot work effectively alone.•The explants of this system can obtain a large number of excellent clones in a short time.•It provides a basis for polyploid breeding to improve germplasm resources. Broussonetia papyrifera (L.) L’Hér. ex Vent. is a perennial woody plant used as source material for papermaking, as woody forage, and as traditional Chinese medicine. In this study, an in vitro adventitious shoot induction procedure for B. papyrifera root explants was developed and evaluated the frequency of adventitious shoot regeneration. It showed that the culture medium, treatment with plant growth regulators, explant developmental stage, explant inoculation mode and genotype significantly affected explant regeneration efficiency. The results suggested that the best medium was half-strength Murashige and Skoog (1/2 MS) medium supplemented with 1.0 mg/L 6-benzyladenine (BA), 0.1 mg/L α-naphthalene acetic acid (NAA), 0.05 mg/L indole-3-butyric acid (IBA), explants derived from roots at the third development stage, inoculation by horizontal planting without cutting, and the genotype was GZ2, delivering a regeneration frequency of 84.44% and the maximum proliferation coefficient was 5.02. The optimal condition for inducing adventitious shoot rooting was 1/2 MS supplemented with 0.1 mg/L NAA. Under this condition, the maximum rooting rate of adventitious shoot was 82.22%, and the root grew strongly. Furthermore, the survival rate of transplanted seedlings was > 90%. Although the regeneration system was influenced by the B. papyrifera genotype, it is still effective for all genotypes studied. Using this novel system, B. papyrifera root explants can attain high induction rates and proliferation coefficients.