SEEDLING PROPAGATION OF SEAWEED Gracilaria gigas BY TISSUE CULTURE

Availability of seaweed seedlings continously  is needed to improve productivity. Tissue culture is one of the methods used to support the seedlings needs. This study was conducted to evaluate the growth of seedlings seaweed of Gracilaria gigas at the propagation stages through tissue culture. The study begins with the supplying of seaweed seedlings G. gigas through culture stage. Explants with 2 cm initial length were cultured in 2 L sea water media enriched by fertilizer 20 mL/L. Explants were maintained for 7 weeks with media renewed weekly. Seedlings acclimatization stage was done by using plastic container with 20 L sea water for 8 weeks. The treatment given was the addition of an organic fertilizer with doses of 0,025; 0,05 and 0,1 mL/L. On-growing of seeds carried out in net box measuring 50x50x50 cm³ in the sea for 7 weeks. The result showed final survival rate of the explants culture was above 90%. While at  acclimatization stage, dose of 0,05 mL/L organic fertilizer tends to provide growth of seedling better than the other doses. The growth rate of seaweed seedlings in on-growing stage in the sea after 7 weeks was 3,57%/day.