High-efficiency micropropagation of dormant buds in spine base of red pitaya (Hylocereus polyrhizus) for industrial breeding

Abstract

By the systematical optimization on explants sterilizing, induction and multiplication of adventitious shoots, rooting and seedling transplanting, the high-efficient regeneration system and domestication transplanting technology for red pitaya (Hylocereus polyrhizus) were established using dormant buds in spine base as primary materials. Results showed that the optimal surface sterilization procedure of red pitaya explants (nodal segments with one spine base) was 0.2% mercuric chloride (HgCl2) treatment for 7 min. The appropriate medium formulation for adventitious shoot induction and proliferation of sterilized red pitaya explants was Murashige and Skoog's medium (MS) supplemented with 5.5 mg/L 6-benzyladenine (6-BA) and 0.1mg/L a-naphthaleneacetic acid (NAA), and maximum average number (6.4) of adventitious shoots per explant and maximum average plantlet height (2.8 cm) were achieved within 30 days. An optimal formulation of half-strength MS medium (1/2 MS) added with 0.5 mg/L NAA and 0.3 mg/L indole-3-butyricacid (IBA) produced an average of 7.21 roots per explant with highest (92%) rooting response when inoculating 4 adventitious shoots per bottle. The tissue-cultured seedlings of red pitaya display a survival rate of up to 100% by optimized procedure of domestication and transplantation.