Seasonal variation in growth and carrageenan yield of Kappaphycus alvarezii (Doty) Doty farmed using mass selection in Bungin Permai Coastal Waters, South Konawe District, Southeast (SE) Sulawesi, Indonesia

Two methods, tissue culture, and mass selection are generally used to improve the quality of the seedlings of the red algae K. alvarezii. Mass selection is relatively new to be adapted to the Indonesian seaweed farming. In this study we attempted to cultivate the seaweed for 10 months (February-November 2013) in Bungin Permai coastal waters, South Konawe, Indonesia. Cultivation was performed for 30 days of each cycle, using long-line method. Each rope contained had distance between clumps of 15-, 20-, 25- and 30-cm. The selection was carried out until 9th generation. The results showed that the daily growth rates (DGRs) among treatments were found to vary and tended to have seasonal variation. Minimum DGRs occurred in October while the maximum was in April/May. The DGRs range was from 3.81±1.80%/day to 8.32±1.12%/day while mean annual DGRs of 15-, 20-, 25- and 30- cm PD were 6.46±1.98, 6.62±2.00, 6.74±2.01, and 6.90±2.03%/day, respectively. No significant differences was found among four different planting distance. The mean carrageenan (semi-refined carrageenan/SRC) yields were varied among treatments and tended also to have seasonal variation. Minimum SRC of all treatments was varied and occurred in March/June while the maximum SRC were in May/October/November. The carrageenan yields range were from 31.53±2.04% to 48.91±5.05%. The highest mean annual SRC was recorded for 15-cm planting distance (PD) (42.02 ± 3.38%) followed by 30-cm PD (41.58 ± 2.95%), 20-cm PD (41.56 ± 6.03%) and 25-cm PD (41.45 ± 4.09%). The quality of cultivars produced from the selection met international specifications suggesting that mass selection for longer period could be 'a new method" to produce better quality of seedlings.