Study on Virus-free and Tissue Culture and Rapid Propagation Technology from Stem Tips of Different Varieties of Purple Yam

To screen suitable culture media for inducing stem tips, promoting virus-free seedling proliferation, and rooting of purple yam, as well as substrates for transplanting and domesticating regenerated seedlings in vitro, in order to provide healthy seedlings for production. Three kinds of purple yam were used as test materials, and different concentrations of 6-BA, NAA, KT, and GA₃ were added to MS medium to study the effects of different hormone concentration ratios on stem tip induction, subculture proliferation, and rooting. In vitro regenerated seedlings were transplanted into seedbeds of imported mud charcoal soil, perlite, and coconut coir with different ratios, and the effects of different substrate ratios on their transplant survival rate were observed. The results showed that: In MS medium supplemented with 1.0 mg·L⁻¹ 6-BA + 0.1 mg·L⁻¹ NAA, Mount Wuyi purple yam, Hutou mountain purple yam, Zhenghe sweet potato had the highest shoot tip seedling rate, which was 77.78%, 77.78% and 71.11%, respectively; The proliferation coefficient of Mount Wuyi purple yam was the highest in MS medium supplemented with 1.0 mg·L⁻¹ 6-BA + 0.5 mg·L⁻¹ KT + 0.3 mg·L⁻¹ NAA + 0.1 mg·L⁻¹ GA₃ + 0.2 g·L⁻¹ AC, which was 4.6. The proliferation coefficient of Hutou mountain purple yam and Zhenghe sweet potato was the highest in MS medium supplemented with 0.5 mg·L⁻¹ 6-BA + 0.2 mg·L⁻¹ KT + 0.1 mg·L⁻¹ NAA + 0.1 mg·L⁻¹ GA₃ + 0.2 g·L⁻¹ AC, which were 4.83 and 4.82 respectively; Mount Wuyi purple yam, Hutou mountain purple yam and Zhenghe sweet potato had the best root growth on MS medium supplemented with 0.5 mg·L⁻¹ IBA + 0.5 mg·L⁻¹ NAA + 0.5 mg·L⁻¹ CCC + 0.5 g·L⁻¹ AC; The survival rate of the three purple yam varieties was the highest when transplanted in peat soil 100% matrix, which were 82.7%, 80.0%, and 82.0% respectively.