Micropropagation of Piper hancei, A Phytophthora, and nematode-resistant Piper species

Piper hancei, a wild species in the genus Piper, has been widely used in Chinese herbal medicinal prescriptions for the treatment of rheumatism, asthma, and arthritic conditions. It is resistant to pathogenic species of Phytophthora and nematodes. This study developed a rapid method for micropropagation of this species, aimed at mass-producing plantlets to serve as rootstocks in the production of disease-resistant pepper. The most effective sterilization method for the stem segment was shaking with a 2% Ridomil Gold (Syngenta) fungicide solution for 30 minutes, followed by a 60 minutes treatment of 2% Antisuper 80wp (Greenfarm) bactericide solution, and then with 10% NaClO for 10 minutes, achieving infection-free survival rate of 37.78%. The optimal medium for shoot regeneration from stem segments was Murashige and Skoog (MS) medium supplemented with 1.0 mg/l 6-Benzylaminopurine (BAP), yielding 1.83 shoots/sample. The medium for in vitro shoot multiplication was basal MS supplemented with 1.0 mg/l BAP and 2.0 mg/l kinetin, producing 4.87 shoots/cluster, with an average shoot height of 1.9 cm. Root formation was most suitable in MS medium supplemented with 1.5 mg/l indole butyric acid, yielding 7.43 roots/shoot, with a root length of 1.97 cm and a shoot height of 3.41 cm. Piper hancei plantlets were successfully transplanted to the nursery with a survival rate of 80.55% after 6 weeks, averaging 4.49 leaves and 5.64 cm in height.