In vitro shoot micropropagation of Gracilaria verrucosa using plant growth dual regulators

Gracilaria verrucosa, an agar producing seaweed, is the highest and most cultivated seaweed in Indonesia. However, its productivity is still low and has not met the global demand for agar. In addition, the lack of good quality seed stocks of this species becomes serious problem. Therefore, an efficient G. verrucosa in vitro culture could be an alternative to solve this obstacle. However, little is known about this method of cultivation. The present study aimed to determine the effect of dual plant growth regulators (IAA and BAP) applications on the shoot micropropagation of G. verrucosa. Intercalar explants of G. verrucosa were grown into PES medium supplemented by both IAA and BAP in various concentrations (0; 0.1; 0.3; 0.5 mg L^-1) for 30 days. Single BAP at 0.5 mg L^-1 treatment showed the best result in all parameters measured, including growth rate (0.42% day^-1), percentage of explant producing shoot (56%) and the number of shoot per explant (2.64 shoots explant^-1).