Objective Purple sweet potato〔Ipomoea Batatas(L.)Lam〕from Vietnam is of excellent quality with uniform tuber and good commodity but low yield and urgently needs genetic improvement of yield traits. Somatic embryogenesis is the basis of rapid reproduction and stable sex, which is of great significance to the genetic improvement of purple sweet potato. The explants of Vietnam small purple sweet potato were treated with hormones to study the somatic embryo regeneration pathway. The experiment provided a new method for screening new materials with high yield and good quality of purple sweet potato by somaclonal variation.

Method Purple sweet potato from Vietnam was used as the material, and the leaf and stem segments were used as explants. The effects of plant growth regulation substance types(6-BA, NAA, 2, 4-D and ABA)and ratios on the purple sweet potato from Vietnam were discussed. Somatic embryogenesis and plant regeneration system for purple sweet potato from Vietnam were established.

Result The leaf and stem segments induced callus culture mediau were the same and the degree of difficulty was consistent. The induction formula was MS + 1.0 mg/L 6-BA + 0.2 mg/L NAA. The normal callus was induced to form embryonal callus and 2, 4-D played an important role, and other hormones played an auxiliary role. The induction formula was MS + 0.1 mg/L 6-BA + 2.0 mg/L 2, 4-D. Somatic embryos were induced from embryonic callus and ABA played an important role and suitable medium for further development and differentiation was MS + 0.1 mg/L 6-BA + 0.2 mg/L NAA +0.5 mg/L ABA.

Conclusion The best induction formula for callus of leaves and stems was MS + 6-BA 1.0 mg/L 6-BA + 0.2 mg/L NAA. The callus was transformed into embryogenic callus by MS + 0.1 mg/L 6-BA + 2.0 mg/L 2, 4-D. Somatic embryo formation from embryogenic callus was treated with MS + 0.1 mg/L 6-BA + 0.2 mg/L NAA+ 0.5 mg/L ABA.