Acacia mangium x A. auriculiformis micropropagation in a non-sterile environment

Autoclaving eliminates microbial contamination during micropropagation, but the process is complex, time-consuming and expensive. Chemical sterilisation also effectively disinfects culture media and is relatively simple and cost-effective. Prior studies have focused on the effects of chemical sterilisation on bud induction, but the effects of sterilant on proliferation and rooting are unknown. We investigated the effect of sterilant on Acacia mangium x A. auriculiformis bud induction, rooting and subculture rooting. The optimal bud induction medium comprised 1/8 Murashige and Skoog medium + 7 g l(-1) agar + 0.2 g l(-1) chlorothalonil + 0.5 mg l(-1) 6-benzylaminopurine. The maximum bud induction rate (99.54%) with zero contamination was achieved using the third to fifth stem segments collected in October and treated with 0.8 g l(-1) carbendazim for 3 min. The maximum rooting rate (97.62%) was attained using a rooting medium consisting of 7 g l(-1) agar + 0.2 g l(-1) chlorothalonil + 1.5 mg l(-1) indolebutyric acid + 0.5 mg l(-1) naphthaleneacetic acid. Proliferation ratio and subculture duration were positively correlated. The maximum proliferation rate (3.58%) was realised in the fourth subculture rooting. Chlorothalonil can effectively replace autoclaving of A. mangium x A. auriculiformis bud induction and rooting media. The present study provides insights for improving the rapid propagation method of Acacia sp. and a new direction for the development of micropropagation technology.